JP3724145B2 - Electron emitting device and method for manufacturing the same, image display device and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron-emitting device that emits electrons and a method for manufacturing the same, and an image display device including the electron-emitting device and a method for manufacturing the same, and more particularly to a configuration using particulate diamond.
[0002]
[Prior art]
Development of a micro-electron emission element is actively performed as an electron source for a thin display or an emitter part of a micro-vacuum device capable of high-speed operation.
[0003]
Conventionally, as the electron-emitting device, a “heat emission type” device in which a voltage of several kilovolts or more is applied to a material such as tungsten heated to a high temperature has been used. Research and development of “cold cathode type” electron-emitting devices capable of emitting electrons even with a voltage has been actively conducted from the viewpoint of reducing power consumption.
[0004]
Various types of such cold cathode devices have been reported, but field emission type and avalanche amplification type using pn and Schottky junction are generally used.
[0005]
A field emission type cold cathode device is a cone-shaped tip made of a refractory metal such as silicon (Si) or molybdenum (Mo) by applying a voltage to the gate electrode and applying an electric field to the cold cathode portion. Electrons are emitted from the portion, and have features such as miniaturization and integration by using a fine processing technique.
[0006]
In the avalanche amplification type using a semiconductor material, a reverse bias voltage is applied to the pn and Schottky junction portions to cause avalanche amplification, thereby heating electrons and emitting electrons from the emitter portion.
[0007]
[Problems to be solved by the invention]
In general, the characteristics required as a cold cathode element are that a high current can be stably obtained by low voltage and low power consumption driving.
[0008]
Here, a so-called “Spindt type”, which is one of the field emission type cold cathode devices that have been generally produced, is a cone-shaped with a sharp protrusion, and the amount of electron emission obtained is It was highly dependent on the tip shape.
[0009]
That is, in order to stably obtain a high current by driving at a low voltage and low power consumption, as a material used for a cold cathode device, (1) in order to facilitate the emission of electrons in a small electric field, the electron affinity is small; 2) It must be chemically stable, and (3) it must have excellent wear resistance and heat resistance.
[0010]
However, none of the conventional materials satisfy all of these requirements. That is, when the prior art is viewed from the above viewpoint, the field emission type element has a large dependency of the emission current amount on the shape of the emitter portion, and its fabrication and control are very difficult, and the surface of the material used There was also a problem in terms of stability.
[0011]
In this method, each element is a point electron emission source from the cone-shaped tip portion where the electric field is concentrated, and it is difficult to obtain a planar electron emission current from which a large current can be extracted.
[0012]
On the other hand, an avalanche-amplified cold cathode device generally requires a very large amount of current to be applied to the device, so that the device generates heat, resulting in unstable electron emission characteristics and shortened device life. There was a problem.
[0013]
Furthermore, in the avalanche amplification type, the work function amount of the electron emission portion is reduced by providing a cesium layer or the like on the surface of the emitter portion. However, the surface state of a material having a low work function such as cesium is chemically unstable because it is chemically unstable. There was also a problem that the electron emission characteristics were not stable as a result.
[0014]
As described above, the materials and structures used so far do not sufficiently satisfy the characteristics required for electron-emitting devices.
[0015]
Accordingly, an object of the present invention is to provide an electron-emitting device capable of stably obtaining a high current by driving at a low voltage and a method for manufacturing the same, in order to solve the above-described problems in the prior art.
[0016]
It is another object of the present invention to provide an image display device using the above-described electron-emitting device and a method for manufacturing the same.
[0017]
[Means for Solving the Problems]
In order to solve the above problems, the electron-emitting device and the manufacturing method thereof of the present invention, the image display apparatus including the electron-emitting device, and the manufacturing method means thereof are as follows.
[0022]
The present invention of claim 1 comprises at least a step of a conductive layer formed by roughening the surface, including conductive and forming an electron emitting portion composed of aggregates of particles or particles on the conductive layer A method of manufacturing an electron-emitting device , wherein the step of forming the surface of the conductive layer by roughening includes a step of forming the conductive layer by a thermal spraying method. .
[0023]
The present invention of claim 2 includes at least a step of forming a conductive layer by roughening a surface thereof, a step of forming an electron emission portion made of particles or an aggregate of particles on the conductive layer, and the electron emission. and forming an extraction electrode for extracting electrons from part a manufacturing method of including electron-emitting device, the step of forming by roughening the surface of the conductive layer, a thermal spraying method to form the conductive layer A method of manufacturing an electron-emitting device, comprising the step of:
[0025]
The present invention of claim 3 includes at least a step of forming a porous conductive layer, a step of forming an electron emission portion made of particles or an aggregate of particles on the conductive layer, and electrons from the electron emission portion. and forming an extraction electrode for extracting a manufacturing method of including electron-emitting device, the step of forming the porous conductive layer, an electron-emitting device, which comprises a step by spraying method It is a manufacturing method .
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The first invention is an electron-emitting device comprising at least a conductive layer and an electron-emitting portion made of particles or aggregates of particles formed on the conductive layer, wherein the surface of the conductive layer is rough. It is characterized by that.
[0029]
According to a second aspect of the present invention, there is provided an electron including at least a conductive layer, an electron emission portion made of particles or an aggregate of particles formed on the conductive layer, and an extraction electrode for extracting electrons from the electron emission portion. In the emission element, the surface of the conductive layer portion is roughened.
[0030]
A third invention is an electron-emitting device including at least a conductive layer and an electron-emitting portion made of particles or particle aggregates formed on the conductive layer, wherein the conductive layer is porous. It is characterized by that.
[0031]
According to a fourth aspect of the invention, there is provided an electron including at least a conductive layer, an electron emission portion made of particles or an aggregate of particles formed on the conductive layer, and an extraction electrode for extracting electrons from the electron emission portion. An emission element, wherein the conductive layer is porous.
[0032]
The fifth invention includes at least a step of forming a conductive layer by roughening a surface thereof, and a step of forming an electron emission portion made of particles or an aggregate of particles on the conductive layer. This is a method for manufacturing an electron-emitting device.
[0033]
The sixth invention includes at least a step of forming a conductive layer by roughening the surface thereof, a step of forming an electron emission portion made of particles or an aggregate of particles on the conductive layer, and And a step of forming an extraction electrode for extracting electrons.
[0034]
The seventh invention includes at least a step of forming a porous conductive layer and a step of forming an electron emission portion made of particles or an aggregate of particles on the conductive layer. It is a manufacturing method.
[0035]
The eighth invention includes at least a step of forming a porous conductive layer, a step of forming an electron emission portion made of particles or an aggregate of particles on the conductive layer, and for extracting electrons from the electron emission portion. And a step of forming a lead electrode. The method of manufacturing an electron-emitting device, comprising:
[0036]
A ninth aspect of the invention is an image display device comprising at least a plurality of electron-emitting devices and an image forming unit that forms an image by electrons emitted from the plurality of electron-emitting devices, An image display device characterized in that the element is the electron-emitting device described in any one of the first to fourth inventions.
[0037]
A tenth aspect of the invention includes at least a step of manufacturing and arranging a plurality of electron-emitting devices, and a step of manufacturing and arranging an image forming unit that forms an image by electrons emitted from the electron-emitting devices. An image display device manufacturing method, wherein the step of manufacturing and arranging the electron-emitting devices is manufactured by the manufacturing method according to any one of the fifth to eighth inventions. It is a manufacturing method.
[0038]
In the present invention, since the electric field concentration on the particles or particle aggregates 2 constituting the electron emission portion 3 is increased by the above-described configuration, electrons can be taken out only by applying a low voltage.
[0039]
Further, since the particles or particle aggregates 2 constituting the electron emission portion 3 are independent without being in contact with each other, each can be a starting point of electron emission. As a result, the electron emission current from the electron emission portion 3 is a particle Alternatively, the emission of electrons from a plurality of locations of each of the particle aggregates 2 is accumulated, so that a large current can be obtained and at the same time temporal and spatial uniformity can be obtained.
[0040]
Further, according to the present invention, a flat-type image display device with low voltage driving and high luminance using the above-described electron-emitting device can be realized.
[0041]
【Example】
(First embodiment)
FIG. 1 shows a cross-sectional view of a first embodiment of the electron-emitting device of the present invention.
[0042]
As shown in FIG. 1, the conductive layer 1 is formed on the substrate 101, but the surface of the conductive layer 1 is roughened, and the particles or the aggregates 2 of the particles are uneven on the surface of the conductive layer 1. Thus, the electron emission portions 3 are formed by adhering independently without contacting each other.
[0043]
The configuration of FIG. 1 is generally called a diode configuration. A voltage is applied to an electrode (not shown) opposed to the electron emission portion 3 to form particles or particle aggregates 2 constituting the electron emission portion 3. The electric field is concentrated to take out electrons.
[0044]
Here, since the particles constituting the electron-emitting portion 3 or the aggregate 2 thereof are formed on the conductive layer 1 having a rough surface, the electric field concentration is higher than when formed on a flat conductive layer. As a result, electrons can be taken out only by applying a low voltage to the counter electrode (not shown).
[0045]
Further, since the particles or particle aggregates 2 constituting the electron emission portion 3 are independent without being in contact with each other, each can be a starting point of electron emission. As a result, the electron emission current from the electron emission portion 3 is a particle Alternatively, the emission of electrons from a plurality of locations of each of the particle aggregates 2 is accumulated, so that a large current can be obtained and at the same time temporal and spatial uniformity can be obtained.
[0046]
Here, by using diamond as the particles or the aggregate 2 of the particles, the stability of the material surface is obtained, and as a result, the stability of electron emission over time is further increased.
[0047]
In general, there is a report that when the surface of diamond is hydrogen-terminated, the electron affinity becomes negative. From this point of view, the particles or particle aggregates 2 forming the electron emission portion 3 are diamond, and further If the surface is hydrogen-terminated, the effect of the present invention can be further increased.
[0048]
Such diamond particles can be obtained, for example, by pulverizing artificial diamond as obtained by vapor phase synthesis and then exposing it to hydrogen plasma.
[0049]
Further, the same effect can be obtained even if carbon particles partially having a diamond structure are used as the particles or the aggregate 2 of the particles.
[0050]
Also in this case, the effect of the present invention can be similarly increased by using hydrogen termination.
[0051]
The conductive layer 1 functions as an electrode for supplying electrons to the particles or particle aggregates 2 constituting the electron emission portion 3, and is a thin film / thick film of a conductive material including a normal metal, a single layer structure, A multi-layer structure is not required.
[0052]
However, it is preferable to use a low work function material as the conductive layer 1 in consideration of a barrier in injecting electrons from the conductive layer 1 to the particles or the aggregate 2 of the particles.
[0053]
If the structure allows, a configuration in which the substrate 101 and the conductive layer 1 are combined is also possible.
[0054]
(Second embodiment)
FIG. 2 shows a cross-sectional view of the second embodiment of the electron-emitting device of the present invention.
[0055]
The conductive layer 1 is formed on the substrate 101, but the surface of the conductive layer 1 is roughened, and the particles or the aggregates 2 of the particles adhere to the surface of the conductive layer 1 according to the irregularities, and the electron emission portion. 3 is formed.
[0056]
An extraction electrode 4 having an opening at a position corresponding to the electron emission portion 3 is provided at a predetermined interval from the electron emission portion 3.
[0057]
The configuration of FIG. 2 is generally called a triode configuration, in which a voltage is applied to the extraction electrode 4, the electric field is concentrated on the surface of the electron emission portion 3, the electrons are extracted, passed through the opening, and extracted forward. As compared with the diode system of FIG. 1, the configuration as an electron-emitting device is slightly complicated, but the applied voltage for extracting electrons may be low.
[0058]
In the configuration of FIG. 2, the particles constituting the electron emission portion 3 or the aggregate 2 thereof are formed on the conductive layer 1 having a roughened surface, and therefore, on the flat conductive layer. The electric field concentration is higher than that in the case where the electrodes are formed. As a result, electrons can be extracted only by applying a low voltage to the extraction electrode 4.
[0059]
Further, since the particles or particle aggregates 2 constituting the electron emission portion 3 are independent without being in contact with each other, each can be a starting point of electron emission. As a result, the electron emission current from the electron emission portion 3 is a particle Alternatively, the emission of electrons from a plurality of locations of each of the particle aggregates 2 is accumulated, so that a large current can be obtained and at the same time temporal and spatial uniformity can be obtained.
[0060]
Further, specific examples for the particles or the aggregate 2 of the particles and the effects at that time are the same as those in FIG.
[0061]
(Third embodiment)
FIG. 3 is a sectional view showing a third embodiment of the electron-emitting device according to the present invention.
[0062]
Although the conductive layer 1 is formed on the substrate 101, the conductive layer 1 is porous and has irregularities on the surface.
[0063]
Particles or aggregates of particles adhere to the surface of the conductive layer 1 in accordance with the unevenness to form the electron emission portion 3.
[0064]
This configuration is generally called a diode configuration, and the operation and characteristics of this configuration are the same as those in FIG.
[0065]
(Fourth embodiment)
FIG. 4 is a sectional view showing a fourth embodiment of the electron-emitting device according to the present invention.
[0066]
The conductive layer 1 is formed on the substrate 11, and the conductive layer 1 is porous and has irregularities on the surface.
[0067]
Particles or particle aggregates adhere to the surface of the conductive layer 1 to form the electron emission portion 2.
[0068]
This configuration is generally called a triode configuration, and the operation and characteristics of this configuration are the same as those in FIG.
[0069]
(First Example “Method for Manufacturing Electron Emission Device”)
FIGS. 5A and 5B are simplified views of steps for explaining the first embodiment of the method for manufacturing an electron-emitting device according to the present invention.
[0070]
Specifically, it is a manufacturing method of the configuration of the first embodiment of the electron-emitting device of the present invention. Reference numeral 1 denotes a conductive layer, which is formed by roughening the surface (FIG. 5A), and an electron emission portion 3 composed of at least one particle or an aggregate 2 of particles is formed thereon (FIG. 5). 5 (b)).
[0071]
Here, as a method of forming the surface of the conductive layer 1 in a roughened state, for example, the following method may be mentioned.
[0072]
The first method is to use “thermal spraying” as a method for forming the conductive layer 1. According to the thermal spraying, the surface of the film is inevitably roughened, and the surface roughness is used.
[0073]
The degree of roughness can be controlled by the film forming conditions.
Further, the thermal spraying has a feature that a vacuum process is not required and a film can be formed under atmospheric pressure, and the formation cost of the conductive layer 1 is reduced.
[0074]
The second method of roughening the surface of the conductive layer 1 is a method of roughening the surface by blasting the conductive layer 1 formed by any method.
[0075]
According to this method, a conductive layer surface having a sharp protrusion shape can be obtained.
The third method of roughening the surface of the conductive layer 1 is a method of roughening the surface by chemically etching the conductive layer 1 formed by any method.
[0076]
In this case, in the case of wet etching, it is desirable to employ an etching method such as spraying an etching solution in order to obtain larger projections and depressions.
[0077]
A fourth method for roughening the surface of the conductive layer 1 is a method in which the substrate 101 is roughened, and the conductive layer 1 is formed thereon, whereby the formation surface of the conductive layer 1 is made uneven.
[0078]
Examples of the method for roughening the substrate 101 include a blast method and an etching method, which are one of the methods for roughening the conductive layer 1 described above.
[0079]
Moreover, as a method of forming the particle | grains or the aggregate 2 of particles on the conductive layer 1, the following method is mentioned, for example.
[0080]
One is a method in which a solution in which particles or particle aggregates 2 are dispersed is applied to the conductive layer 1 by a method such as spin coating.
[0081]
As another method, the member in which the conductive layer 1 is formed is immersed in a solution in which particles or particle aggregates 2 are dispersed, and ultrasonic vibration is applied to the solution to remove particles in the solution. It is the method of making it adhere to.
[0082]
The third method is a method of attaching particles by electrophoresis.
According to these methods, particles or particle aggregates 2 can be distributed and formed on the conductive layer 1 in an independent state without being in contact with each other.
[0083]
According to the above manufacturing method, an electron-emitting device having the electron-emitting portion 3 formed on the conductive layer 1 on which at least one particle or particle aggregate 2 is roughened is obtained. Since the electric field concentration on the emission part 3 becomes efficient, it becomes possible to manufacture an electron-emitting device capable of extracting electrons by applying a low voltage.
[0084]
Further, according to this manufacturing method, the particles or the particle aggregates 2 are applied to the conductive layer 1 in an independent state without being in contact with each other, so that each particle or particle aggregate 2 becomes an electron emission source. The electrons taken out from the electron emitting portion 3 are accumulated from the individual particles or particle aggregates 2. Therefore, it is possible to manufacture an electron-emitting device that can extract a large current.
[0085]
(Second Embodiment “Method for Manufacturing Electron Emission Device”)
6A to 6C are simplified views of steps for explaining a second embodiment of the method for manufacturing an electron-emitting device according to the present invention.
[0086]
Specifically, it is a manufacturing method of the configuration of the second embodiment of the electron-emitting device of the present invention. Reference numeral 1 denotes a conductive layer, which is formed by roughening the surface (FIG. 6A), and an electron emission portion 3 composed of at least one particle or an aggregate 2 of particles is formed thereon (FIG. 6). 6 (b)).
[0087]
Then, an extraction electrode 4 having an opening at a position corresponding to the electron emission portion 3 is provided at a predetermined interval from the electron emission portion 3 (FIG. 6C).
[0088]
Here, as a method of forming the surface of the conductive layer 1 in a roughened state, a method similar to the configuration in FIG.
[0089]
Further, as a method of forming the particles or the aggregate 2 of the particles in the shape of the conductive layer 1, the same method as that in the previous FIG.
[0090]
6A to 6C, the step (FIG. 6B) for forming the electron emission portion 3 made of at least one particle or particle aggregate 2 corresponds to the electron emission portion 3. Even if the step of providing the extraction electrode 4 having an opening at a location at a predetermined distance from the electron emission portion 3 (FIG. 6C) is reversed, particles or particle aggregates 2 on the extraction electrode 4 are provided. If you can prevent the adhesion of, it will be no problem.
[0091]
(Third embodiment "Method for manufacturing electron-emitting device")
FIGS. 7A to 7B are simplified views of steps for explaining a third embodiment of the method for manufacturing an electron-emitting device according to the present invention.
[0092]
Specifically, it is a manufacturing method of the configuration of the third embodiment of the electron-emitting device of the present invention. Reference numeral 1 denotes a conductive layer. The conductive layer 1 is porous (FIG. 7A), and an electron emission portion 3 composed of at least one particle or an aggregate 1 of particles is formed thereon (FIG. 7). 7 (b)).
[0093]
Here, as a method of forming the conductive layer 1 to be porous, for example, a method by “thermal spraying” can be mentioned.
[0094]
By thermal spraying, the film inevitably becomes porous with pores.
Further, the thermal spraying has a feature that a vacuum process is not required and a film can be formed under atmospheric pressure, which leads to a reduction in the formation cost of the conductive layer 1.
[0095]
Moreover, as a method of forming the particle or the aggregate 2 of particles into the conductive layer 1, the same method as that in the previous FIG.
[0096]
(Fourth embodiment "Method for manufacturing electron-emitting device")
FIGS. 8A to 8C are simplified views of steps for explaining a fourth embodiment of the method for manufacturing an electron-emitting device according to the present invention.
[0097]
Specifically, it is a manufacturing method of the configuration of the fourth embodiment of the electron-emitting device of the present invention. Reference numeral 1 denotes a conductive layer, and the conductive layer 1 is porous (FIG. 8A), and an electron emission portion 3 composed of at least one particle or an aggregate 1 of particles is formed thereon (FIG. 8). 8 (b)).
[0098]
An extraction electrode 4 having an opening at a position corresponding to the electron emission portion 3 is provided at a predetermined interval from the electron emission portion 3 (FIG. 8C).
[0099]
Here, as a method for forming the conductive layer 1 to be porous, the same method as described in FIG.
[0100]
Moreover, as a method for forming the particles or the aggregate 2 of the particles into the conductive layer 1, a method similar to the configuration in the previous (FIG. 5) can be given.
[0101]
Further, in FIGS. 8A to 8C, a step (FIG. 8B) of forming an electron emission portion 3 made of at least one particle or an aggregate 2 of particles corresponds to the electron emission portion 3. Even if the step of providing the extraction electrode 4 having an opening at a location at a predetermined distance from the electron emission portion 3 (FIG. 8C) is reversed, particles or aggregates of particles on the extraction electrode 4 The same is true if the adhesion of 2 is prevented.
[0102]
FIG. 9 shows an embodiment of a flat image display apparatus of the present invention.
The electron-emitting device 11 of the present invention is formed on a substrate 12 a that also serves as a part of the envelope 12.
[0103]
Reference numeral 13 denotes an image forming unit, which is an electron drive electrode 13a for driving / controlling acceleration / deflection / modulation etc. of electrons from the electron-emitting device 11, and fluorescence applied to the inner surface of a part 12b of the envelope 12. The phosphor 13b emits light by the driven electrons and displays an image.
[0104]
Here, since the electron-emitting device of the present invention is used as the electron-emitting device 11, it is possible to take out a large current with a low voltage. realizable.
[0105]
10 (a) to 10 (d) show an embodiment of a method for manufacturing a flat panel display according to the present invention. For example, the electron-emitting device 11 of the present invention is formed on the substrate 12a that also serves as a part of the envelope 12 (FIG. 10A).
[0106]
Next, an electronic drive electrode 13a which is a part of the image forming unit is disposed (FIG. 10B), and a part 12b of the envelope having a phosphor 13b applied on the inner surface is installed (FIG. 10C). ), And the inside is evacuated to manufacture the image display device (FIG. 10D).
[0107]
According to this manufacturing method, it is possible to manufacture a flat-panel image display device using the electron-emitting device of the present invention, and thus it is possible to manufacture a flat-panel image display device with low voltage drive and high brightness.
[0108]
【The invention's effect】
As described above, according to the present invention, the particles or the aggregates of the particles are independently applied to each other on the roughened or porous conductive layer without being in contact with each other, It is possible to provide an electron-emitting device that can extract a high current at a low voltage and a method for manufacturing the same.
[0109]
Furthermore, according to the present invention, it is possible to provide a flat-panel image display device using the electron-emitting device and driven at a low voltage and having high brightness, and a method for manufacturing the same.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a first embodiment of the electron-emitting device of the present invention. FIG. 2 is a cross-sectional view of a second embodiment of the electron-emitting device of the present invention. FIG. 4 is a cross-sectional view of a fourth embodiment of the electron-emitting device of the present invention. FIGS. 5A and 5B are diagrams illustrating a first method of manufacturing an electron-emitting device of the present invention. Simplified process diagram showing an embodiment [FIG. 6] (a) to (c) Simplified process diagram showing a second embodiment of the method of manufacturing an electron-emitting device of the present invention [FIG. 7] (a), (b) FIGS. 8A to 8C are simplified process diagrams showing a fourth embodiment of the method for manufacturing an electron-emitting device according to the present invention. FIGS. FIGS. 9A and 9B are diagrams showing one embodiment of a flat panel image display device according to the present invention. FIGS. 10A to 10D are simplified process diagrams illustrating one embodiment of a manufacturing method of the flat plate image display device according to the present invention. Description of the code]
DESCRIPTION OF SYMBOLS 1 Conductive layer 2 Particle | grains or aggregate of particles 3 Electron emission part 4 Extraction electrode 13 Image formation part

Claims (3)

At least, a conductive layer forming roughened the surface, met production method of the conductive layer including electron-emitting device and forming the electron emitting portion composed of aggregates of particles or particles hand,
The method of manufacturing an electron-emitting device, wherein the step of forming the surface of the conductive layer by roughening includes a step of forming the conductive layer by a thermal spraying method . At least a step of forming a conductive layer by roughening a surface thereof, a step of forming an electron emission portion made of particles or an aggregate of particles on the conductive layer, and a drawer for extracting electrons from the electron emission portion and forming an electrode by a method for producing including electron-emitting devices,
The method of manufacturing an electron-emitting device, wherein the step of forming the surface of the conductive layer by roughening includes a step of forming the conductive layer by a thermal spraying method . At least a step of forming a porous conductive layer, a step of forming an electron emission portion made of particles or particle aggregates on the conductive layer, and an extraction electrode for extracting electrons from the electron emission portion are formed and a step method for manufacturing a including electron-emitting devices,
The method of manufacturing an electron-emitting device, wherein the step of forming the porous conductive layer includes a step of spraying .

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