JP4036572B2 - Manufacturing method of electron emission source - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an electron emission source that emits electrons, an electron emission source manufactured by the method, and a fluorescent display using the electron emission source.
[0002]
[Prior art]
Conventionally, an emitter formed of an electron emitting material that emits electrons is disposed between a cathode conductor and a gate electrode (extraction electrode), and a voltage is applied between the cathode conductor and the gate electrode to thereby generate electrons from the emitter. Some electron emission sources that emit light have been put into practical use and are being studied.
[0003]
Field electron emission source for emitting electrons by the action of the electric field, electrons are emitted into a vacuum even at room temperature the applied field of the metal or the surface of a semiconductor such as through the barrier by which the tunnel effect to about 10 9 ^{V /} m It is a phenomenon and has many excellent points such as energy saving and longer life compared with an electron source (thermal electron emission source) using thermal energy. Examples of the emitter material include semiconductors such as silicon, metals such as tungsten and molybdenum, diamond-like carbon (DLC), and the like.
[0004]
Since the extraction current is determined by the electric field strength applied to the emitter, it is necessary to use an emitter having a sharp tip in order to construct a high-efficiency electron emission source driven at a low voltage. When an emitter is formed using a semiconductor, metal, or the like, it is necessary to process the tip of the electron emission portion into a sharp needle shape.
However, it is not easy to process the tip of the semiconductor, metal or the like into a sharp needle shape, and there is a problem that a large-scale device is required, which makes it extremely expensive.
[0005]
In view of the above, carbon nanotubes are recently attracting attention as electron emission materials. A carbon nanotube is a linear carbon material with an outer diameter of 1 to several tens of nanometers, and its shape is easy to cause electric field concentration and has a sufficient structure to allow electron emission at a low voltage. Since carbon, which is a material, is characterized by being chemically stable and mechanically strong, it is a material suitable for an emitter.
[0006]
For example, as an electron emission source using carbon nanotubes, there is an electron emission source disclosed in Japanese Patent Application Laid-Open No. 10-31954. The electron emission source has a structure in which a paste material containing carbon nanotubes is printed on a cathode conductor or a resistance layer deposited on the cathode conductor and then fired, and a rib-like gate electrode is disposed above the paste material. There are some, and electrons can be emitted by applying a voltage between the cathode conductor and the gate electrode.
In addition, when the electron emission source is used as an electron emission source of a fluorescent light emitting display, an anode electrode coated with a phosphor is provided so as to face the electron emission source, and these are disposed in a vacuum hermetic container. A fluorescent light-emitting display is formed by disposing in the above. By adopting such a configuration, the phosphor is excited by electrons emitted from the carbon nanotubes by driving the gate electrode and the anode electrode to a predetermined positive potential, and light emission display can be performed.
[0007]
[Problems to be solved by the invention]
In the electron emission source described in the above publication, a carbon material containing carbon nanotubes is made into a paste, and this paste material is merely dried and fired after printing, so that it becomes a solvent for pasting the carbon material. The contained component remains after firing, and the emitter is formed in a state where it covers the surface of the carbon nanotube, so that the work function of the emitter is increased. As a result, it is difficult to emit electrons at a low voltage, and the electron emission efficiency is low. In addition, it is difficult to clean an electron emission source having a fine and complicated structure as an electron emission source.
[0008]
In addition to carbon nanotubes, fullerenes, nanoparticles, nanocapsules, carbon nanohorns, and the like are attracting attention as minute carbon materials. However, when emitters are formed using these paste materials, they are low in the same manner as described above. There is a problem that it is difficult to cause electron emission with high efficiency at a voltage.
Therefore, when the electron emission source obtained by the above method is used for a fluorescent light emitting display, there is a problem that it is difficult to obtain a high luminance light emitting display by driving at a low voltage.
[0009]
The present invention has been made in view of the above problems, and uses a carbon material having at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules, and carbon nanohorns, and is a low-voltage driven and highly efficient electron. The issue is to enable release.
[0010]
[Means for Solving the Problems]
According to the present invention, an insulating substrate is provided in a method of manufacturing an electron emission source in which an emitter is disposed between a cathode conductor and a gate electrode, and electrons are emitted from the emitter by applying a voltage between the cathode conductor and the gate electrode. Depositing a cathode conductor on the cathode conductor, depositing a paste material containing at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules and carbon nanohorns on the cathode conductor to form an emitter; There is provided a method of manufacturing an electron emission source, comprising: a step of etching a surface of an emitter by dry etching; and a step of forming a gate electrode at a position spaced from the emitter.
[0011]
According to the present invention, in the method of manufacturing an electron emission source, an emitter is disposed between the cathode conductor and the gate electrode, and electrons are emitted from the emitter by applying a voltage between the cathode conductor and the gate electrode. A step of depositing a cathode conductor on an insulating substrate; a step of depositing a resistance layer on the cathode conductor; and the resistance layer includes at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules, and carbon nanohorns. A step of forming an emitter by depositing a paste material; a step of etching the surface of the emitter by dry etching; and a step of forming a gate electrode at a position spaced from the emitter. A method for manufacturing an electron emission source is provided.
[0012]
Here, as the dry etching, reactive ion etching using an etching gas containing H ₂ or O ₂ , or an etching gas containing a C _x H _y gas or a C _x H _y F _z gas is used. Also good.
According to the present invention, in the electron emission source in which an emitter is disposed between the cathode conductor and the gate electrode and electrons are emitted from the emitter by applying a voltage between the cathode conductor and the gate electrode, A carbon material having at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules, and carbon nanohorns is applied to the cathode conductor directly or via a resistance layer, and the carbon material is etched by dry etching. An electron emission source characterized by being formed by processing is provided.
[0013]
Further, according to the present invention, the anode electrode on which the electron emission source and the phosphor are deposited is disposed in the vacuum hermetic container, and the electrons emitted from the electron emission source are projected onto the phosphor. In the fluorescent light-emitting display that performs light-emitting display, there is provided a fluorescent light-emitting display that uses the electron emission source.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals.
1 to 3 are side sectional views for explaining a method of manufacturing an electron emission source according to an embodiment of the present invention.
[0015]
First, in FIG. 1, a silver paste is deposited by screen printing on an insulating substrate 101 such as borosilicate glass and fired to form a cathode conductor 102 with a thickness of about 5 μm.
Next, as shown in FIG. 2, a resistor material is deposited on the cathode conductor 102 to a thickness of about 5 μm by screen printing to stabilize electron emission and prevent overcurrent when the electrodes are short-circuited. Then, the resistance layer 201 is formed by firing. As the material of the resistance layer 201, a RuO ₂ -based resistor material or the like can be used.
[0016]
Next, as shown in FIG. 3, a paste material containing carbon nanotubes is applied onto the resistance layer 201 by screen printing to form an emitter 301 containing carbon nanotubes with a thickness of about 10 μm.
As the paste material containing carbon nanotubes, a carbon material containing carbon nanotubes produced by an arc discharge method can be used which is well dispersed in a solution of ethyl cellulose dissolved in terpione by ultrasonic waves or the like. . Further, in order to increase the adhesion strength with the resistance layer 201, an inorganic adhesive (glass-based, metal alkoxide, etc.) remaining after firing can be added as appropriate.
[0017]
Next, the temperature is raised to a predetermined temperature (for example, about 100 ° C.) to dry the paste-like emitter 301, and then fired in the atmosphere at a predetermined temperature (for example, about 500 ° C.). Then, the cathode substrate 302 in which the cathode conductor 102, the resistance layer 201, and the emitter 301 are laminated and deposited on the insulating substrate 101 is completed.
[0018]
Next, the cathode substrate 302 formed as described above is etched by reactive ion etching (RIE).
FIG. 6 is a view showing an apparatus for performing the RIE process on the cathode substrate 301. The cathode substrate 302 is disposed on the lower electrode 603 so as to face the upper electrode 602 provided in the chamber 601, and is not shown. The etching gas is supplied by injecting and exhausting the etching gas through the gas injection and exhaust ports, and high-frequency power (for example, 13.56 MHz) is supplied from the high-frequency power source 604 between the grounded upper electrode 602 and lower electrode 603. Supply. Thereby, the surface of the emitter 301 of the cathode substrate 302 is etched.
[0019]
Here, as an etching gas, for example, an etching gas containing H ₂ or O ₂ , a C _x H _y system such as CHF ₃ , CF ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₅ F _12, or C etching gas, etc. containing _x H _y F _z based gas can be used.
By the etching process, a solvent component or the like deposited on the surface of the carbon nanotube of the emitter 301 is removed, and the carbon nanotube itself of the emitter 301 is exposed on the surface of the emitter 301.
[0020]
Next, as shown in FIG. 4, a glass insulating layer (rib) 401 is formed to a thickness of about 40 μm in the recess between the emitters 301 on the cathode substrate 302, and on the insulating rib 401. A rib-like gate electrode 403 is formed by stacking and depositing a gate electrode 402 having a thickness of about 5 μm, thereby completing a field emission type electron emission source.
As a method for forming the rib-like gate electrode 403, for example, after forming the gate electrode 402 on a transfer substrate (not shown), the insulating rib 401 is laminated on the gate electrode 402 and further insulated. Alternatively, an adhesive (not shown) may be deposited on the adhesive rib 401 and transferred to the position shown in FIG.
[0021]
In the electron emission source thus obtained, application of a predetermined voltage between the cathode conductor 102 and the gate electrode 402 causes concentration of the electric field in the carbon nanotube exposed by the emitter 301. Therefore, the electron emission start voltage is lowered, and it is possible to generate electrons with high efficiency at a low voltage. In addition, the presence of the resistance layer 201 can stabilize electron emission and prevent overcurrent when the gate electrode 402 and the emitter 301 are short-circuited.
[0022]
In this embodiment, the etching process on the surface of the emitter 301 is performed before the rib-shaped gate electrode 403 is formed, but may be performed after the rib-shaped gate electrode 403 is formed.
Moreover, although RIE was used for the etching process, various dry etchings such as plasma etching and sputter etching can be used.
Furthermore, although the gate electrode is formed of a rib-shaped gate electrode, a gate electrode having another structure such as a mesh-shaped gate electrode can also be used.
In addition, the resistance layer 201 is unnecessary when stabilization of electron emission and prevention of overcurrent at the time of electrode short-circuit are not particularly required or when it can be realized by another structure. In this case, the emitter 301 is directly deposited on the cathode conductor 102.
[0023]
Moreover, although the carbon material containing a carbon nanotube was used as the material of the emitter 301, a carbon material containing fullerene, nanoparticles, nanocapsules, or carbon nanohorns can also be used. That is, as the material of the emitter 301, a paste material containing a carbon material having at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules, and carbon nanohorns can be used.
[0024]
Next, a fluorescent light emitting display is formed using the electron emission source. FIG. 5 is a partially cutaway side view of the fluorescent light emitting display according to the embodiment of the present invention, and is an example using the electron emission source manufactured as described above. In FIG. 5, the fluorescent light emitting display includes an insulating substrate 101 as a rear substrate formed of borosilicate glass, a light-transmitting insulating substrate 501 as a front substrate formed of borosilicate glass, and an insulating substrate 101. , And a sealing glass 504 for sealing the periphery of 501, and a vacuum hermetic container in which the inside is maintained in a vacuum state.
[0025]
Further, as described above, on the inner surface of the insulating substrate 101, the cathode conductor 102, the resistance layer 201 continuously formed on the cathode conductor 102, and the emitter 301 continuously formed on the resistance layer 201 are formed. Are laminated.
Further, a rib-like gate electrode 403 in which an insulating rib 401 and a gate electrode 402 are laminated is formed on the inner surface of the insulating substrate 101 in a recess between the emitters 301.
On the other hand, on the inner surface of the insulating substrate 501, an anode electrode 502 and a phosphor 503 attached to the anode electrode 502 are stacked.
[0026]
Note that in the case of a fluorescent light-emitting display that displays characters, graphics, etc., the cathode conductor 102, the anode electrode 502, and the gate electrode 402 are each formed in a matrix or a specific electrode is a solid. The other electrodes are formed in a matrix shape, and the pattern is appropriately formed according to the purpose. Also, in the case of a fluorescent light emitting display used as a pixel light emitting element of a large screen display device, the pattern of each electrode is appropriately selected and formed.
[0027]
In the fluorescent light emitting display having the above-described configuration, the phosphor 503 emits light by supplying a drive signal having a predetermined voltage to the cathode conductor 102, the gate electrode 402, and the anode electrode 502, and in accordance with the formation pattern and drive signal of each electrode. Further, it is possible to perform light emission display such as characters and graphics, or light emission display as a light emitting element.
At this time, since electric field concentration occurs in the carbon nanotube exposed on the surface of the emitter 301, it is possible to obtain a high-luminance and high-quality light-emitting display by low voltage driving.
[0028]
As described above, in the method for manufacturing an electron emission source according to the embodiment of the present invention, an emitter is disposed between a cathode conductor and a gate electrode, and a voltage is applied between the cathode conductor and the gate electrode to thereby form the emitter. In a method for manufacturing an electron emission source that emits electrons from a substrate, a step of depositing a cathode conductor 102 such as silver or aluminum on an insulating substrate 101 such as borosilicate glass, carbon nanotubes, fullerenes, nanoparticles, nanocapsules, and carbon nanohorns Forming a emitter 301 by applying a carbon material having at least one of the above as an electron emission material and applying a paste material containing the electron emission material to the cathode conductor; firing the emitter 301; Etch the surface of the fired emitter 301 by dry etching such as RIE. A step of processing, the gate electrode at a position spaced from the emitter 301 (e.g., a rib-like or mesh-like gate electrode) is characterized by comprising a step of forming a 402. Accordingly, the solvent component or the like deposited on the surface of the carbon material is removed, and the carbon nanotube, fullerene, nanoparticle, nanocapsule, or carbon nanohorn itself that is the carbon material is exposed, and electric field concentration occurs in the exposed carbon material. Therefore, it becomes possible to manufacture an electron emission source that generates electrons with high efficiency at a low voltage.
[0029]
In addition, a step of depositing the resistance layer 201 formed of a RuO ₂ -based resistance material on the cathode conductor 102 is added between the step of depositing the cathode conductor 102 and the step of forming the emitter 301 during the manufacturing process. You may make it do. That is, a step of depositing the cathode conductor 102 on the insulating substrate 101, a step of depositing the resistance layer 201 on the cathode conductor 102, and a carbon nanotube, fullerene, nanoparticle, nanocapsule and carbon nanohorn on the resistance layer 201. A step of depositing a paste material containing a carbon material having at least one of the above and forming the emitter 301. As a result, it is possible not only to manufacture an electron emission source that generates electrons efficiently at a low voltage as described above, but also to stabilize the electron emission and to prevent overcurrent when the electrode is short-circuited. A source manufacturing method is provided.
[0030]
Further, according to the embodiment of the present invention, the emitter 301 is disposed between the cathode conductor 102 and the gate electrode 402, and electrons are emitted from the emitter 301 by applying a voltage between the cathode conductor 102 and the gate electrode 402. In the electron emission source, the emitter 301 is formed of a carbon material having at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules, and carbon nanohorns, and directly or via the resistive layer 201 to the cathode conductor 102. An electron emission source is provided in which the carbon material is laminated and the carbon material is etched by dry etching. Therefore, electron emission can be generated with high efficiency at a low voltage, and electron emission can be stabilized and overcurrent can be prevented when an electrode is short-circuited.
[0031]
Furthermore, according to an embodiment of the present invention, an electron emission source such as a fluorescent display tube or a fluorescent light emitting tube, a phosphor, and an anode electrode on which the phosphor is deposited are disposed in a vacuum hermetic container, and the electron emission In a fluorescent light emitting display that performs light emission display by causing electrons emitted from a source to collide with the phosphor, by using the electron emission source obtained as described above as an electron emission source, Voltage drive makes it possible to obtain a high-luminance and high-quality light-emitting display.
[0032]
In the above embodiment, an example of a three-dimensional electron emission source in which the gate electrode 402 is disposed above the cathode conductor 102 has been described. However, both the cathode conductor and the gate electrode are the same on the insulating substrate. It is also possible to configure a planar electron emission source by disposing it on a plane.
[0033]
【Example】
FIG. 7 is a side sectional view showing an apparatus for evaluating the characteristics of an electron emission source according to an embodiment of the present invention, and FIG. 8 is a characteristic diagram of the present embodiment.
The electron emission source used in FIG. 7 is an electron emission source having a structure having no resistance layer between the cathode electrode and the emitter. The cathode conductor 102 and the emitter 301 are formed on the inner surface of one insulating substrate 101 constituting the vacuum envelope 701. The anode electrode 502 is attached to the inner surface of the other substrate 702 so as to face the emitter 301. The emitter 301 is made of a carbon material containing carbon nanotubes.
[0034]
A series circuit of a DC power supply 703 and an ammeter 704 is connected between the cathode conductor 102 and the anode electrode 502.
The distance between the cathode conductor 102 and the anode conductor 502 is 200 μm, and the sizes of the cathode conductor 102 and the emitter 301 are 1 mm × 1 mm square.
[0035]
As the etching method of the emitter 301, RIE processing using the apparatus of FIG. 6 is performed, and the etching conditions are as follows: (1) When the etching gas is O ₂ , the gas flow rate is 50 sccm, and the output of the AC power source 604 is 160W, the pressure in the chamber 601 is 5 Pa, the etching time is 120 sec. (2) When the etching gas is CHF ₃ , the gas flow rate is 80 sccm, the output of the AC power source 604 is 160 W, and the pressure in the chamber 601 is The etching was performed at 5 Pa and an etching time of 120 seconds.
[0036]
In FIG. 8, as is clear from the IV characteristics of the emission current Ie of the emitter 301 and the output voltage Vg (V) of the DC power supply 703, the etching process is performed using CHF ₃ as an etching gas. A larger current was obtained at a lower voltage than when not (untreated). It can also be seen that when O ₂ is used as the etching gas, a large current is obtained at a lower voltage, and the electron emission characteristics are further improved.
[0037]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the manufacturing method of a low voltage and highly efficient electron emission source.
This makes it possible to provide an electron emission source with excellent electron emission characteristics. In addition, it is possible to provide a fluorescent display which can be driven at a low voltage and has high luminance and high quality.
[Brief description of the drawings]
FIG. 1 is a side sectional view for explaining a method of manufacturing an electron emission source according to an embodiment of the present invention, and is a diagram showing a process of depositing a cathode conductor on an insulating substrate.
FIG. 2 is a side sectional view for explaining the method for manufacturing the electron emission source according to the embodiment of the present invention, and is a view showing a process of depositing a resistance layer on the cathode substrate.
FIG. 3 is a sectional side view for explaining a method of manufacturing an electron emission source according to an embodiment of the present invention, and showing a step of depositing an emitter on a resistance layer.
FIG. 4 is a sectional side view for explaining a method of manufacturing an electron emission source according to an embodiment of the present invention, showing a step of depositing a gate electrode.
FIG. 5 is a partially cutaway side view of a fluorescent light emitting display according to an embodiment of the present invention.
FIG. 6 is a diagram for explaining an etching process in the method for manufacturing an electron emission source according to the embodiment of the present invention.
FIG. 7 is a view showing an apparatus for measuring characteristics of an electron emission source according to an embodiment of the present invention.
FIG. 8 is a characteristic diagram of an electron emission source according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 ... Insulation board | substrate 102 ... Cathode conductor 201 ... Resistance layer 301 ... Emitter 302 ... Cathode board 401 ... Rib 402 ... Gate electrode as a front substrate which comprises a vacuum airtight container 501... Insulating substrate 502 as a rear substrate constituting a vacuum hermetic container... Anode electrode 503... Phosphor 504.

Claims (3)

Depositing a cathode conductor on an insulating substrate;
Depositing a paste material containing at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules and carbon nanohorns on the cathode conductor to form an emitter;
Firing the emitter in an atmosphere of about 500 degrees C;
And a step of etching the surface of the emitter by dry etching. Depositing a cathode conductor on an insulating substrate;
Depositing a resistive layer on the cathode conductor;
Depositing a paste material containing at least one of carbon nanotubes, fullerenes, nanoparticles, nanocapsules, and carbon nanohorns on the resistive layer to form an emitter;
Firing the emitter in an atmosphere of about 500 degrees C;
And a step of etching the surface of the emitter by dry etching. The dry etching is reactive ion etching using an etching gas containing H ₂ or O ₂ or an etching gas containing a C _x H _y gas or a C _x H _y F _z gas. A method for manufacturing an electron emission source according to claim 1 or 2.

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