JP2003016912A - Electron emitting element, electron source, image forming device and manufacturing method of electron emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emitting element capable of improving electron emission efficiency and being relatively easily manufactured, a manufacturing method thereof, an electron source equipped with two or more such electron emitting elements and an image forming device with the electron source integrated thereto. SOLUTION: An electron emission layer 106 formed of an electron emitting material is arranged on a first electrode layer 102 within the opening of an insulating layer 104, and as the electron emission layer 106, a catalyst material and a fibrous carbon grown through the catalyst material are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device excellent in electron emission efficiency, a method for manufacturing the same, and an image forming apparatus such as an electron source and an image display device in which the electron-emitting device is incorporated.

[0002]

2. Description of the Related Art Various flat panel display devices have been studied as an image display device to replace a cathode ray tube (CRT) which is currently the mainstream.

A liquid crystal display device (LCD), an electroluminescence display device (ELD) and a plasma display device (PDP) can be exemplified as such a flat type display device. Further, an electron emission display device capable of emitting electrons from a solid to a vacuum has been proposed, and has been attracting attention from the viewpoint of screen brightness and low power consumption.

Conventionally, two types of electron-emitting devices are known, which are roughly classified into a thermoelectron-emitting device and a cold cathode electron-emitting device.

Cold cathode electron emission devices include field emission type (hereinafter referred to as "FE type"), metal / insulating layer / metal type (hereinafter referred to as "MIM type") and surface conduction type electron emission devices. is there.

As an example of the FE type, W. P. Dyke;
W. W. Dolan, Field Emission,
Advance in Electron Phys
ics, 8, 89 (1956) or C.I. A. Spi
ndt, PHYSICAL Properties o
f thin-film field emissio
n cathodes with mollybdeni
um cones, J. Appl, Phys ,. 47,
5248 (1976) and the like are known.

As one of the representative examples of the field emission device disclosed above, there is known a so-called Spindt type field emission device having an electron emission portion formed of a conical conductor.

FIG. 11 shows the structure of a display device incorporating this Spindt-type field emission device (hereinafter referred to as Spindt-type device). FIG. 11 is a structural diagram of a Spindt-type electron-emitting device.

Spindt-type device cathode panel 1110
Is the cathode electrode 110 formed on the support 1101.
2, an insulating layer 1103, a gate electrode 1105 formed on the insulating layer 1103, and a conical electron-emitting portion 1106 formed in an opening 1104 provided in the gate electrode 1105 and the insulating layer 1103. ing.

A predetermined number of electron emitting portions 1106 are arranged in a two-dimensional matrix to form one pixel.

On the other hand, the anode panel 1111 is the substrate 1
A phosphor layer 1108 is formed on the 107 in a predetermined pattern, and the phosphor layer 1108 is formed on the anode electrode 1109.
It has a structure covered with.

Electron emitting portion 1106 and gate electrode 1105
When a voltage is applied between and, electrons are extracted from the tip of the electron emitting portion 1106 by the resulting electric field.

The electrons are attracted to the anode electrode 1109 on the anode panel 1111 side, and the anode electrode 1109
It collides with the phosphor layer 1108 which is a light emitting layer formed between the substrate 109 and the substrate 1107.

As a result, the phosphor layer 1108 is excited and emits light, and a desired image can be obtained.

The operation of this field emission device is basically controlled by the signal voltage applied to the gate electrode 1105.

The electron emission characteristic of the Spindt-type field emission device is that the gate electrode 110 forming the upper end of the opening 1104 is formed.
5 largely depends on the distance from the edge of No. 5 to the tip of the electron emission portion 1106.

This distance largely depends on the processing accuracy such as the processing accuracy of the shape of the opening 1104 and the dimensional accuracy of the diameter.

However, it is extremely difficult to actually form a metal layer having a uniform film thickness over the entire substrate of a large area by vertical vapor deposition, and some in-plane variation and lot-to-lot variation cannot be avoided. .

Due to this variation, the image display characteristics of the display device, for example, the brightness of the bright spots, vary.

Moreover, there are problems that a large-scale vapor deposition apparatus is required and throughput is reduced.

The electrons emitted from the electron emitting portion 1106 draw a trajectory orthogonal to the equipotential surface. In the Spindt-type element, the equipotential surface is curved along the surface of the conical electron emitting portion 1106. Therefore, the orbits diverge near the phosphor layer.

When color display is assumed, such orbital divergence leads to mislanding of electrons, which may cause color turbidity between adjacent pixels.

An example of the MIM type is C.I. A. Mea
d. , Operation of Tunnel-Em
ision Devices, J. et al. Apply. Ph
ys. , 32,646 (1961) and the like are known.

In a recent example, Toshiaki.
Kusunoki, Fluctuation-free
electron emission from n
on-formed metal-insulator
-Metal (MIM) cathodes Fabri
cated by low current Anod
ic oxidation, Jpn. J. Appl. P
hys. vol. 32 (1993) pp. L1695,
Mutsumi suzuki et al An MI
M-Cathode Array for Cahto
de luminescent Displays, I
DW'96, (1996) pp. 529 mag have been studied.

As an example of the surface conduction type, the report by Elinson (MI Elinson Radio Eng.
electron Phys. , 10 (1965)) and the like. In this surface conduction electron-emitting device, electrons are emitted by passing a current through a thin film of a small area formed on a substrate in parallel to the film surface. It utilizes the phenomenon.

As the surface conduction type element, one using the SnO ₂ thin film described in Ellison's report, one using an Au thin film, (G. Dittmer. Thin Solid) is used.
Films. 9, 317 (1972)), by an ITO thin film (M. Hartwell and CG.
Fonstad, IEEE Trans. ED Con
f. , 519 (1983)) and the like have been reported.

Next, a conventional surface conduction electron-emitting device will be described with reference to FIG. FIG. 12 is a schematic view of a conventional surface conduction electron-emitting device.

FIG. 12A shows the device viewed from directly above, and FIG. 12B shows it from the side.

In FIG. 12, 1201 is a substrate,
Reference numeral 1202 is an element positive electrode, and 1203 is an element negative electrode, which is connected to a power source (not shown).

Reference numerals 1204 and 1205 denote conductive thin films, and the conductive thin film 1204 and the element positive electrode 1202 and the conductive thin film 1205 and the element negative electrode 1203 are electrically connected.

Element positive electrode 1202, element negative electrode 1203
Has a thickness of several tens of nm to several μm. On the other hand, the thickness of the conductive thin films 1204 and 1205 is 1 [n
m] to several tens of [nm].

Reference numeral 1206 denotes a gap, which makes the conductive thin film 1204 and the conductive thin film 1205 electrically discontinuous.

Conventionally, in these surface conduction electron-emitting devices, the electron-emitting portion is generally formed in advance by conducting a current called a current-forming process on the conductive thin film before the electron emission.

That is, the energization forming means that a direct current voltage or a very slow rising voltage, for example, about 1 V / min is applied to both ends of the conductive thin film to energize the conductive thin film to locally break, deform, or alter the conductive thin film, and then electrically. That is, the electron emitting portion is formed in a high resistance state.

Further, by introducing an organic gas in a vacuum and energizing, a process called activation, by depositing carbon and a carbon compound on the tips of the conductive thin films facing each other across the insulating layer, the electron emission characteristics are improved. An improved electron emitting portion is formed.

The surface conduction electron-emitting device that has been subjected to energization forming treatment and activation treatment is one in which electrons are emitted from the electron-emitting portion by applying a voltage to the above-mentioned conductive thin film and passing a current through the device. .

Carbon and carbon compounds include, for example, graphite, so-called HOPG, PG (GC), H
OPG is a nearly perfect graphite crystal structure, PG is a crystal grain structure of about 200 Å, and the crystal structure is somewhat disordered, GC
Indicates that the crystal grain becomes about 20 Å and the disorder of the crystal structure is further increased.

These are diamond-like carbon, amorphous carbon, a mixture of amorphous carbon and fine crystals of graphite and diamond, and the film thickness thereof is preferably in the range of 500 Å or less, and in the range of 300 Å or less. Is more preferable.

In the flat panel display device using the surface conduction electron-emitting device described in the above-mentioned conventional example, the gap between the electrodes is formed and the carbon compound is deposited by energization such as forming and activation. There is a large variation in the gap between the electrodes and in the deposited carbon compound, particularly in the gap between the elements, which may cause variations in electron emission between the elements. Further, since all emitted electrons contributing to light emission are scattered electrons, the efficiency is theoretically about 7% at maximum.

On the other hand, there is a proposal disclosed in Japanese Patent Application Laid-Open No. 8-115654 as a field emission device capable of solving these drawbacks of the Spindt type device and the surface conduction type device.

The proposed device disclosed in the above publication is shown in FIG.
3 will be used for the explanation. FIG. 13 shows Japanese Unexamined Patent Publication No. H8-11565.
FIG. 4 is a structural diagram of a field emission device disclosed in Japanese Patent Publication No. 4 publication.

In this device, a cathode electrode 1302 and a gate electrode 1303 are provided so as to face each other with an insulating layer 1304 interposed therebetween, an opening 1306 penetrating the gate electrode 1303 and the insulating layer 1304 is formed, and the cathode electrode 1302 and the gate electrode 1302 are formed. Electrons are applied from the cathode electrode 1302 side to the opening 1306 by applying a voltage between the electrodes 1303.
Is configured to be discharged through.

In this element, the thin film 1305 made of the electron emitting material is provided so as to be exposed in the opening 1306, so that the equipotential surface Em in the opening 1306 becomes substantially flat along the surface of the thin film 1305. It is formed.

Therefore, the trajectory of the electrons emitted from the opening 1306 does not largely fluctuate, and the electrons can reach the target phosphor layer 1307.

Since the upper surface of the thin film 1305 is located deeper than the lower surface of the insulating layer 1304, a larger electric field is applied to the thin film 1305 as it is closer to the center of the opening 1306. .

As a result, a higher emission current density can be obtained as it is closer to the center of the opening 1306.

In the flat type device as described above, the thin film 1
Reference numeral 305 is a member corresponding to the electron emitting portion of the Spindt-type element.

Since the distance between the electron-emitting portion and the gate electrode 1303 can be substantially determined by the thickness of the insulating layer 1304 in the flat type element, control of this distance is much easier than in the Spindt type element. Is.

Therefore, the electron emission characteristics of the electron emission layer can be easily made uniform even on a large-area support, and the brightness of the image on the display device can be made uniform.

In the flat type device, the distance between the thin film 1305 corresponding to the electron emission portion and the gate electrode 1303 is sufficiently larger than that in the Spindt type device.
A lift-off method is adopted to form 305, and a thin film 1305 is formed.
Even if the residue is generated, the thin film 1305 and the gate electrode 1303 are unlikely to be short-circuited by the residue.

Therefore, the planar type element can greatly improve the manufacturing yield and the operational reliability as compared with the Spindt type element.

USP is proposed as a device in which CNTs are grown by using a catalyst in the above-mentioned flat type element to form a device.
There is 5872422.

[0053]

However, in the conventional flat-type electron-emitting device disclosed in Japanese Patent Laid-Open No. 8-115654, the shape of the electron-emitting layer is a Spindt-type device or USP5872422.
Not a sharp "point" as disclosed in
In addition, since the distance between the electron emitting portion and the gate electrode is long, the electric field strength in the vicinity of the electron emitting portion is weaker than that of the Spindt-type element, and the size of the opening is also smaller than that of the Spindt-type element. Since it is large, the effect of confining the electric field inside the opening is weakened, and electric field concentration is less likely to occur in the vicinity of the electron emission layer.

In other words, the planar electron-emitting device has a lower electron emission efficiency than the Spindt-type device and requires a higher gate voltage to obtain an emission electron current equivalent to that of the Spindt-type device. It is difficult to reduce power consumption and eventually power consumption.

Therefore, the present invention can improve the electron emission efficiency and is relatively easy to manufacture, an electron-emitting device and a method of manufacturing the same, and an electron source and an electron provided with a plurality of such electron-emitting devices. An object is to provide an image forming apparatus incorporating a source.

[0056]

In order to achieve the above object, in an electron-emitting device according to the present invention, a first electrode and a second electrode having an opening are connected to the opening of the second electrode. An electron-emitting device that is provided to face each other with an insulating layer having an opening communicating with each other, and emits electrons by applying a voltage between the first electrode and the second electrode, On the first electrode in the opening of the insulating layer,
An electron emission layer made of an electron emission substance is arranged, and a catalyst substance and fibrous carbon grown through the catalyst substance are used as the electron emission layer.

Further, a first electrode and a second electrode are provided so as to face each other with an insulating layer in between, and minute holes penetrating the second electrode and the insulating layer are formed, and the minute holes are further formed. An electron emission layer made of an electron emission material is formed on a portion of the first electrode, and a voltage is applied between the first electrode and the second electrode so that electrons pass through the micropores. In the electron-emitting device configured to emit, the uppermost end of the electron-emitting layer is located at a position lower than the lower end of the insulating layer of the electron-emitting device including the first electrode in the microhole. The existing electron-emitting device is characterized in that a catalyst substance and fibrous carbon grown through the catalyst substance are used as the electron-emitting layer.

The second electrode is made of a material in which the fibrous carbon does not grow.

When the insulating layer has a thickness of 500 nm, the second electrode has a thickness of 100 nm, the micropores have a diameter of 500 nm, and the electron emission layer has a thickness of 20 nm, the electron emission is performed. The layer is present in a portion within 150 nm from the center of the micropore on the first electrode.

Further, the portion of the first electrode other than the micropores and the second electrode are covered with a material in which the fibrous carbon does not grow.

Further, the material of the electron emission portion of the first electrode is made of a material in which fibrous carbon grows through the catalyst substance.

Further, the material in which the fibrous carbon does not grow is a material made of at least one of Ta, Cr, Au, Ag, Pt, and the same kind of material as the material forming the catalyst substance. And

Further, the material by which the fibrous carbon grows through the catalyst substance is Ti, Zr, Nb oxide or oxide semiconductor.

The fibrous carbon includes graphite nanofibers (GNF) and carbon nanotubes (CN) obtained by decomposing and growing a hydrocarbon gas using the catalyst substance.
T), amorphous carbon (a-C: H), diamond-like carbon (DLC), or any mixture thereof.

The catalyst material is Pd, Ni, F
It is characterized in that it is made of e, Co or any alloy thereof.

Furthermore, the electron source according to the present invention is characterized in that a plurality of the electron-emitting devices are arranged.

Further, the low-potential supply wiring for driving the electron source and the high-potential supply wiring are arranged in a matrix.

Further, the image forming apparatus according to the present invention comprises the electron source and an image forming member which forms an image by the electrons emitted from the electron source, and each electron emitting element of the electron source is formed by an information signal. It is characterized by controlling the electron emission amount of.

Further, the image forming member is a phosphor.

Further, in the method of manufacturing an electron-emitting device according to the present invention, the step of forming the first electrode on the substrate and the first step
Removing a part of the electrode of, and embedding a catalytic substance, which is a material for growing fibrous carbon, in the removed part,
Forming an insulating layer on the first electrode; forming a second electrode on the insulating layer; and forming micropores penetrating the second electrode and the insulating layer, respectively. The method includes exposing a catalytic substance, which is a material for growing fibrous carbon, and forming the fibrous carbon as an electron emission layer on a region of the catalytic substance of the first electrode.

Further, a step of forming a first electrode layer made of a material in which fibrous carbon grows through a catalyst substance on the substrate, and a catalyst layer made of the catalyst substance is formed on the first electrode layer. And a step of forming a layer of a material on which the fibrous carbon does not grow on the catalyst layer, a step of forming an insulating layer on the layer of a material on which the fibrous carbon does not grow, and a step of forming a first layer on the insulating layer. Forming the second electrode, and forming micropores penetrating the second electrode, the insulating layer, and the layer of material in which the fibrous carbon does not grow, and exposing the catalyst substance in the micropore. And a step of forming the fibrous carbon as an electron emission layer on the exposed region of the catalytic material.

As described above, according to the present invention, the first electrode and the second electrode
Of the second electrode and the electrode of
Of the electron and the insulating layer are formed, and electrons are emitted through the micropore by applying a voltage between the first electrode and the second electrode. In the emission device, an electron emission layer made of an electron emission material is formed on a part of the first electrode,
It is characterized in that the applied voltage is small and the emitted electrons are emitted without being scattered because the catalyst substance and the fibrous carbon grown through the catalyst substance are used as the electron emission layer.

Alternatively, according to the present invention, the first electrode and the second electrode are provided so as to face each other with the insulating layer interposed therebetween, and the minute holes penetrating the second electrode and the insulating layer are formed, and An electron emission layer made of an electron emission material is formed in a part of the hole on the first electrode, and the first electrode and the second electrode are formed.
In the electron-emitting device configured such that electrons are emitted through the micropores by applying a voltage between the electrode and the electrode, the electron-emitting surface of the electron-emitting layer is insulated from the electron-emitting device including the first electrode. An electron-emitting device that is located deeper in the micropores than the layer-side surface, and is characterized in that a catalytic substance and fibrous carbon grown through the catalytic substance are used as the electron-emitting layer. .

[0074]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
The materials, shapes, relative arrangements thereof, etc., are not intended to limit the scope of the present invention thereto only unless otherwise specified.

Further, in the following drawings, the same members as those described in the above drawings are designated by the same reference numerals.

(One Embodiment of Electron-Emitting Device) FIG. 1 is a structural diagram of one embodiment of the electron-emitting device according to the present invention.
In FIG. 1, 101 is a substrate such as glass or silicon, and 1
Reference numeral 02 denotes a material layer in which fibrous carbon grows through a catalytic substance made of Ti or the like, a first electrode layer as a first electrode described in the claims of the present application, and 103 denotes a first electrode layer of the present application. Electron emission layer 1 as a catalytic material according to claims
06 is a catalyst substance layer, 104 is an insulating layer such as SiO ₂ for separating the first electrode layer 102 and the second electrode layer 105, and 105 is a second layer described in the claims of the present application.
The second electrode layer 106 serving as the electrode of the above is an electron emission layer made of graphite nanofiber (GNF) as the fibrous carbon described in the claims of the present application.

Although the lower end of the insulating layer 104 on the side of the first electrode layer 102 is lower than the uppermost end of the electron emission layer 106 in FIG. 1, the electron emission element of this embodiment has, for example, FIG. Like the electron-emitting device shown in FIG.
The structure may be such that the uppermost end of 6 is located at a position lower than the lower end of the insulating layer 104 including the first electrode layer 102 in the micropores.

The configuration of FIG. 1 will be described in more detail. A first electrode layer 102 is deposited on a base 101, a catalyst substance layer 103 is deposited on a part of the first electrode layer 102, and an opening is formed on the first electrode layer 102 including the catalyst substance layer 103. The insulating layer 104 is laminated on the insulating layer 104, and the insulating layer 104 is sandwiched between the first electrode layer 102 and the second electrode layer 105.

Then, the electron emission layer 106 is formed in the central portion of the first electrode layer 102 including the catalyst material layer 103 exposed in the opening.

Here, the second electrode layer 105 is preferably made of a material in which fibrous carbon does not grow. Also, the first
It is preferable that the portion of the electrode layer 102 other than the micropores and the second electrode layer 105 are covered with a material in which fibrous carbon does not grow.

As such a material in which fibrous carbon does not grow, at least one of Ta, Cr, Au, Ag, Pt and the same kind of material as the material forming the catalyst substance can be mentioned.

Further, Ti, Zr, Nb oxides or oxide semiconductors can be used as the material used for the first electrode layer 102, in which fibrous carbon grows through the catalytic substance.

Further, such a catalytic substance is Pd, N
i, Fe, Co or any alloy thereof can be mentioned.

As a material forming the preferable electron emission layer 106, a carbon compound, in particular, fibrous carbon can be mentioned.

In this case, the emission electron current density required for a normal display device can be obtained with an electric field intensity of 5 × 10 ⁵ V / cm or less.

Further, since the fibrous carbon is an electric resistor, it is possible to make the emitted electron currents obtained from the respective openings uniform, and therefore it is possible to suppress the luminance variation when incorporated in the image forming apparatus. Becomes

Further, since fibrous carbon has extremely high resistance to the adsorption action of the residual gas in the image forming apparatus, the life of the field emission device can be extended.

The growth of fibrous carbon is described in J. Mater. R
es. , Vol8, No12, p3233, the contact angle between the catalyst material and the underlying substrate, or the surface energy.

The "fibrous carbon" used in the present invention is "columnar material containing carbon as a main component", "linear material containing carbon as a main component", or "fiber containing carbon as a main component". Alternatively, the term "fiber containing carbon as a main component" specifically includes graphite nanofiber (GNF), carbon nanotube (CNT), amorphous carbon (a-C: H) and its fiber, diamond-like carbon (DLC). Alternatively, it includes any combination thereof, and preferably has a length of 20 nm or less among the above “fibrous carbon”.

FIG. 2 is a schematic diagram of a measurement / evaluation system of the electron-emitting device shown in FIG. Further, in FIG. 2, the same members as those shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

Similar to FIG. 1 described above, in FIG. 2, 101 is a substrate such as glass or silicon, 102 is a Ti oxide semiconductor or the like, and is a material layer in which fibrous carbon grows through a catalytic substance. 1 is an electrode layer, 103 is a catalyst material layer, 104 is a first electrode layer 102 and a second electrode layer 105 such as SiO _2.
Is an insulating layer for separating from each other, 105 is a second electrode layer, and 106 is an electron emission layer made of GNF or the like.

Reference numeral 107 denotes a power source for applying the voltage Vg between the first electrode layer 102 and the second electrode layer 105, and 108.
Is an anode electrode for capturing the emission current Ie emitted from the electron emission portion of the device.

109 is a high voltage power source for applying a voltage to the anode electrode 108, and 110 is an electron emission layer 106 of the device.
It is an ammeter for measuring the emission current Ie emitted further.

As an example, the measurement can be performed with the voltage of the anode electrode 108 in the range of 1 kV to 10 kV and the distance H between the anode electrode 108 and the electron-emitting device in the range of 2 mm to 8 mm.

Next, with reference to FIG. 3, the trajectories of the electrons emitted from the electron-emitting device shown in FIG. 1 will be described. FIG. 3 is a schematic diagram of a simulation result emitted in the opening of the electron-emitting device shown in FIG. In the figure, 301 indicates an equipotential surface, and 302 indicates an electron beam trajectory.

As shown in the drawing, since the concave equipotential surface 301 is formed, even when the electrons are emitted from the periphery of the electron-emitting device, they collide with the insulating layer and the second electrode layer which are the wall surfaces around the opening. -It can be seen that it goes out of the opening without being scattered.

However, in order to take the emission electron beam trajectory as shown in FIG. 3, the emission portion must be inside the opening end of the minute hole.

Next, with reference to FIG. 4, a simulation result of calculating the relationship between the position of the emission film (electron emission layer 106) and the scattering range of the beam in the electron emission device shown in FIG. 1 will be described. FIG. 4 is an emission film (electron emission layer 106) in the electron emission device shown in FIG.
FIG. 6 is a schematic diagram of a simulation result in which the relationship of the scattering range of the beam with respect to the position of is calculated.

FIG. 4A shows a device structure as a model.
In the figure, D is the diameter of the micropore opening, D = 500 nm, Y is the thickness of the insulating layer, Y = 500 nm, H is the thickness of the electron emission portion, H = 20 nm, and X is from the micropore end of the emission film. It was a distance. In FIG. 4B, the value of X is X = 30 nm to 100 nm.
The range in which the emission film is scattered with respect to X when changed to is shown.

As shown in FIG. 4, in a film having a film thickness of 20 nm, X = 100 nm, that is, the emission film diameter d (the diameter of the electron emission layer, that is, the size of the electron emission layer in the X direction) = 30.
If it is not less than 0 nm, the electrons emitted from the outer peripheral portion of the emission film will be scattered.

That is, in the example shown in FIG. 4, the electron emission layer needs to be present in a portion within 150 nm from the center of the micropores on the first electrode.

Next, an application example of the embodiment of the electron-emitting device according to the present invention will be described. As such an application example, consider a case where a plurality of surface conduction electron-emitting devices to which the above-described electron-emitting device embodiments of the present invention are applied are arranged on a substrate to realize, for example, an electron source or an image forming apparatus. be able to.

Various arrangements of electron-emitting devices can be adopted. As an example, a large number of electron-emitting devices arranged in parallel are connected at both ends, and a large number of rows of electron-emitting devices are arranged (referred to as a row direction), and in a direction orthogonal to this wiring (referred to as a column direction). There is a ladder-like arrangement in which a control electrode (also referred to as a grid) arranged above the electron-emitting device controls and drives electrons from the electron-emitting device.

Separately, a plurality of electron-emitting devices are arranged in a matrix in the X and Y directions, and one of the electrodes of the plurality of electron-emitting devices arranged in the same row is commonly used for wiring in the X direction. An example is one in which the electrodes are connected and the other electrodes of the plurality of electron-emitting devices arranged in the same column are commonly connected to the wiring in the Y direction. This is a so-called simple matrix arrangement.

An electron source and an image forming apparatus obtained by arranging a plurality of electron-emitting devices according to the embodiments of the present invention will be described below with reference to FIGS. 5 to 7. FIG. 5 is a schematic plan view of an embodiment of the electron source according to the present invention.
6 is a partially cutaway perspective view of an embodiment of an image forming apparatus according to the present invention using the electron source shown in FIG. 5, and FIG. 7 is a block diagram of the image forming apparatus shown in FIG.

In FIG. 5, reference numeral 501 denotes an electron source substrate, and 50
Reference numeral 2 is an X-direction wiring, and 503 is a Y-direction wiring. Also, 5
Reference numeral 04 denotes the embodiment of the electron-emitting device according to the present invention described above, 5
05 is a connection.

Here, if the capacitance of the elements increases due to the arrangement of a plurality of electron-emitting devices 504, in the matrix wiring shown in FIG. 5, the waveform is rounded by the capacitance component even if a short pulse accompanying the pulse width modulation is added. However, there are problems such as being unable to obtain the expected gradation.

In order to solve this, an interlayer insulating layer (provided on the rear plate 605) as shown in FIG. It is advisable to adopt a structure that reduces the increase of the capacitance component in the above.

In FIG. 5, m X-direction wirings 502 are provided.
Are made of DX1, DX2, ... DXm, and are made of an aluminum-based wiring material having a thickness of about 1 μm and a width of 300 μm formed by a vapor deposition method. However, the wiring material,
The film thickness and width are appropriately designed.

On the other hand, the Y-direction wiring 503 has a thickness of 0.5 μm.
It is composed of n wirings of DY1, DY2, ... DYn having a width of m and a width of 100 μm, and is formed similarly to the X-direction wiring 502.

These m X-direction wirings 502 and n Y-wirings
An interlayer insulating layer (not shown) is provided between the directional wiring 503 and the directional wiring 503 to electrically separate the two (m and n are:
Both are positive integers).

The interlayer insulating layer (not shown), which is an insulating film provided between the wirings, has a thickness of about 0.8 μm formed by sputtering or the like.
Of SiO ₂ .

The entire area of the substrate 501 on which the X-direction wiring 502 is formed is partially formed in a desired shape, and in particular, in order to withstand the potential difference at the intersection of the X-direction wiring 502 and the Y-direction wiring 503, the present embodiment is used. Then, the element usage amount per element is 1p
Below F, the thickness of the interlayer insulating layer was determined so that the device breakdown voltage was 30V. The X-direction wiring 502 and the Y-direction wiring 503
Are respectively drawn out as external terminals.

The electron-emitting device 50 according to the embodiment of the present invention.
The pair of electrodes (not shown) forming part 4 are electrically connected to the m X-direction wirings 502, the n Y-direction wirings 503, and the connection wires 505 made of a conductive metal or the like.

A scanning signal applying means (not shown) for applying a scanning signal for selecting the row of the electron-emitting devices 504 according to the embodiment of the present invention arranged in the X direction is connected to the X-direction wiring 502. .

On the other hand, on the Y-direction wiring 503, a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 504 according to the embodiment of the present invention arranged in the Y-direction according to an input signal. Are connected.

The drive voltage applied to each electron-emitting device is
It is supplied as a difference voltage between the scanning signal and the modulation signal applied to the element. In the embodiment of the present invention, the Y-direction wiring is connected to have a high potential and the X-direction wiring is connected to have a low potential. That is, the Y-direction wiring is the high-potential supply wiring described in the claims of the present application, and the X-direction wiring is the low-potential supply wiring described in the claims of the present application.

By making such a connection, the beam converging effect, which is a feature of the embodiment of the present invention, was obtained.

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

Next, an image forming apparatus constructed by using such an electron source having a simple matrix arrangement will be described with reference to FIG. FIG. 6 shows a display panel of an image forming apparatus using the electron source having the simple matrix arrangement shown in FIG. 5 and using soda lime glass as a glass substrate material.

In FIG. 6, reference numeral 601 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged, 605 is a rear plate to which the electron source substrate 601 is fixed, 610 is an inner surface of a glass substrate 607, and claims of the present application are described. Film 608 or metal back 609 as a phosphor as an image forming member of
Etc. is a face plate on which are formed.

Reference numeral 606 denotes a support frame, and the support frame 606 includes a rear plate 605 and a face plate 6.
10 is connected using frit glass or the like.

Reference numeral 612 denotes an envelope, which is 450
It is formed by sealing by firing at a temperature range of 10 minutes.

Reference numeral 604 denotes an electron emitting portion, which includes 602 and 60.
Reference numeral 3 denotes an X-direction wiring and a Y-direction wiring, respectively, which are connected to the pair of device electrodes of the electron-emitting device according to the embodiment of the present invention.

The envelope 612 comprises the face plate 610, the support frame 606, and the rear plate 605, as described above.

Also, by installing a support member (not shown) called a spacer between the face plate 610 and the rear plate 605, the envelope 612 having sufficient strength against atmospheric pressure can be constructed.

The metal back 609 is obtained by performing a smoothing process (usually called “filming”) on the inner surface of the fluorescent film after the fluorescent film is produced, and then depositing Al using vacuum deposition or the like. Can be made with.

On the face plate 610, a transparent electrode (not shown) is provided on the outer surface side of the fluorescent film 608 in order to further enhance the conductivity of the fluorescent film 608.

A high voltage is applied to the high voltage terminal (Hv) 611.

When performing the above-mentioned sealing, in the case of color, it is necessary to associate each color phosphor with the electron-emitting device.
Sufficient alignment is essential.

Next, the structure of an embodiment of the image forming apparatus according to the present invention will be described with reference to FIG.

The scanning circuit 702 shown in FIG. 7 is provided 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 0 [V] (ground level), and is electrically connected to the terminals Dx1 to Dxm of the display panel 701.

Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 703, and can be formed by combining switching elements such as FETs.

In the case of this example, the DC voltage source Vx is a drive voltage applied to an unscanned element based on the characteristics (electron emission threshold voltage) of the electron-emitting element according to the embodiment of the present invention. Is set to output a constant voltage such that is equal to or lower than the electron emission threshold voltage.

The control circuit 703 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 703 is a synchronization signal separation circuit 70.
Based on the synchronization signal Tsync sent from the control unit 6, the control signals Tscan and Tmry are generated for each unit.

The sync signal separation circuit 706 is a circuit for separating the sync signal component and the luminance signal component from the NTSC system television signal input from the outside, and uses a general frequency separation (filter) circuit or the like. Can be configured.

The sync signal separated by the sync signal separation circuit 706 is composed of a vertical sync signal and a horizontal sync signal.
Here, for convenience of explanation, it is shown as a Tsync signal.

The luminance signal component of the image separated from the television signal is represented as a DATA signal for convenience. This DATA signal is input to the shift register 704.

The shift register 704 is for serially / parallel-converting the DATA signal serially input in time series for each line of the image.
It operates on the basis of the control signal Tsft sent from H.03. That is, the control signal Tsft is output to the shift register 704.
It can be said that it is the shift clock.

The data of one line of the serial / parallel-converted image (corresponding to drive data for N electron-emitting devices) is output from the shift register 704 as N parallel signals Id1 to Idn.

The line memory 705 is a storage device for storing data for one line of an image for a required time, and stores the contents of Id1 to Idn as appropriate in accordance with the control signal Tmry sent from the control circuit 703. The stored contents are output as Id1a to Idna and input to the modulation signal generator 707.

The modulation signal generator 707 outputs the image data Id.
1a to Idna is a signal source for appropriately driving and modulating each of the electron-emitting devices according to the present embodiment, and an output signal of the signal source is provided in the display panel 701 through the terminals Doy1 to Doyn. Applied to the electron-emitting device according to the embodiment.

As described above, the electron-emitting device according to the embodiment of the present invention has the following basic characteristics with respect to the emission current Ie.

That is, a clear threshold voltage V is required for electron emission.
There is th, and electron emission occurs only when a voltage higher than Vth is applied.

For voltages above the electron emission threshold,
The emission current also changes according to the change in the voltage applied to the element.

From this, when a pulsed voltage is applied to this element, for example, no electron emission occurs even if a voltage below the electron emission threshold is applied, but when a voltage above the electron emission threshold is applied. An electron beam is output.

At this time, the intensity of the output electron beam can be controlled by changing the pulse peak value Vm. Further, it is possible to control the total amount of charges of the electron beam output by changing the pulse width Pw.

Therefore, as a method of modulating the electron-emitting device according to the input signal, a voltage modulation method, a pulse width modulation method or the like can be adopted. When carrying out the voltage modulation method, as the modulation signal generator 707, a circuit of the voltage modulation method is used that generates a voltage pulse of a fixed length and appropriately modulates the peak value of the pulse according to the input data. be able to.

In implementing the pulse width modulation method,
As the modulation signal generator 707, a pulse width modulation type circuit that generates a voltage pulse having a constant crest value and appropriately modulates the width of the voltage pulse according to input data can be used.

Here, in FIG. 7, the shift register 7
04 and the line memory 705 used a digital signal system.

The modulation signal generator 707 has, for example, a D / A
A conversion circuit is used, and an amplification circuit or the like is added as necessary.

In the case of the pulse width modulation method, the modulation signal generator 707 compares, for example, a high-speed oscillator and a counter (counter) for counting the number of waves output by the oscillator with the output value of the counter and the output value of the memory. Comparator
The circuit which combined these was used.

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.

As for the input signal, the NTSC system is mentioned, but the input signal is not limited to this, and PAL,
In addition to the SECAM system and the like, a TV signal (for example, a high-definition TV including the MUSE system) system including a large number of scanning lines can be adopted.

[0157]

The present invention will be described in more detail with reference to examples. (Embodiment 1) First, a method of manufacturing the electron-emitting device shown in FIG. 1 will be described with reference to FIG. 8 is shown in FIG.
3 is a schematic view of Example 1 of the method for manufacturing the electron-emitting device shown in FIG. However, among the members shown in FIG. 8, the same members as the members shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, as described above, in FIG.
Reference numeral 1 is a substrate such as glass or silicon, 102 is a first electrode layer which is a material layer on which fibrous carbon grows through a catalytic substance such as Ti, 103 is a catalytic substance layer, and 104 is SiO _2.
Is an insulating layer for separating the first electrode layer 102 and the second electrode layer 105 from each other, 105 is a second electrode layer, and 106 is an electron emission layer made of GNF or the like.

The manufacturing process of the electron-emitting device of this embodiment will be described in detail below with reference to FIGS.

(Step 1) n ⁺ type Si as the substrate 101
After the substrate is sufficiently washed, Ti which becomes the first electrode layer 102 is formed.
Is deposited by 500 nm sputtering (FIG. 8).
(A)).

(Step 2) Further, the resist is patterned to cover the portions other than the portion for forming electron emission (FIG. 8).
(B)).

(Step 3) The first electrode portion is etched by 5 nm (FIG. 8C).

(Step 4) Pd, which is a catalytic substance, is deposited to a thickness of 5 nm on the cathode portion etched in Step 3, and the air
Medium, oxidized at 300 ° C. to form PdO. Planarization is performed by CMP (FIG. 8D).

(Step 5) Next, the PdO is flattened by CMP. Here, CMP will be described below. That is, CMP is an abbreviation for chemical mechanical polishing,
The content is to carry out polishing by utilizing a chemical etching action by a chemical component contained in the polishing material and a mechanical polishing action originally possessed by the polishing agent.

Chemical Mechanical Polishing (CMP)
As an example, it is conceivable to remove the reaction product generated by the chemical reaction between the chemical components contained in the abrasive and the sample to be polished by mechanically polishing with an abrasive and a polishing cloth. To be

In the CMP process, after the sample to be polished is attached to a rotatable polishing head, the surface of the sample to be polished is pressed against a rotating platen (polishing platen) to perform polishing. A pad (polishing cloth) is attached to the surface of the platen, and polishing is performed by the slurry (abrasive material) to which the pad is attached.

(Step 6) S, which is the insulating layer 104, is formed thereon.
io ₂ is deposited to a thickness of 500 nm and Pt, which is the second electrode layer 105, is deposited to a thickness of 100 nm (FIG. 8 (e)).
Wider size than the above Pd part, specifically diameter 500
nm through holes are generated by argon milling (FIG. 8).
(F)).

(Step 7) Finally, as the fibrous carbon which is an electron emitting substance, the above-mentioned GNF was formed to a thickness of 20 nm by a thermal CVD method using C ₂ H ₄ as a source gas. The substrate temperature at this time is 4
It was 80 ° C. (FIG. 8 (g)).

Using this device, emission electron measurement was evaluated as an image beam in a vacuum container. The measuring system at this time is shown in FIG.

As the driving voltage, 15 V was applied to the gate electrode. The anode voltage was Va = 5 kV, and the distance H between the electron-emitting device and the anode electrode was H = 1 mm. Here, an anode electrode coated with a phosphor was used.

As a result, the diameter of the light emitting point on the phosphor surface is 30.
It was about 1/2 of the conventional value in μm. The gate current was also 1/100 or less of the anode current.

(Embodiment 2) Next, Embodiment 2 of the method for manufacturing an electron-emitting device according to the present invention will be described with reference to FIG. FIG. 9 is a schematic view of Example 2 of the method for manufacturing an electron-emitting device according to the present invention.

FIG. 10 shows an electron-emitting device manufactured by the manufacturing method of the second embodiment. Figure 10
FIG. 10 is a structural diagram of an electron-emitting device manufactured by the method for manufacturing the electron-emitting device shown in FIG. 9.

First, the manufacturing method of the second embodiment will be described with reference to FIG.
Will be described with reference to.

(Step 1) After thoroughly cleaning the n ⁺ type Si substrate 901, 500 n of Ti to be the first electrode layer 902a is removed.
m, Pd to be the catalyst layer 903 was formed to a thickness of 5 nm, and then Ai
PdO is obtained by heating at 300 ° C. in r.

Next, the first electrode 90 as a layer of the material in which the fibrous carbon according to the claims of the present application does not grow.
2b of Ta is 50 nm, and the insulating layer 904 is SiO.
₂ is 500 nm, and Ta serving as the second electrode 905 is 10 n
m film is formed (FIG. 9A).

(Step 2) Further, the resist 923 is patterned to cover a portion other than a portion for forming electron emission (FIG. 9).
(B)).

(Step 3) The second electrode 90 is formed as a micropore.
5, the insulating layer 904 and the first electrode 902b are penetrated to form a hole having a diameter of 500 nm (FIG. 9C).

(Step 4) Finally, the above-mentioned GNF as fibrous carbon which is an electron emitting substance is formed to a thickness of 20 nm by a thermal CVD method using C ₂ H ₄ as a raw material gas to form an electron emitting layer 906. The substrate temperature at this time is 480 ° C. (FIG. 9).
(D)).

When the characteristics of the device manufactured through the above steps were measured in the same manner as in (Example 1), equivalent characteristics were obtained.

[0181]

As described above, according to the present invention, it is possible to provide a flat type electron-emitting device capable of improving electron emission efficiency and relatively easy to manufacture, an electron source using the same, and an image forming apparatus. Could be provided.

[Brief description of drawings]

FIG. 1 is a structural diagram of an embodiment of an electron-emitting device according to the present invention.

FIG. 2 is a schematic diagram of a measurement / evaluation system of the electron-emitting device shown in FIG.

FIG. 3 is a schematic diagram of a simulation result emitted in the opening of the electron-emitting device shown in FIG.

FIG. 4 is a schematic diagram of a simulation result in which a relation between a position of an emission film (electron emission layer 106) and a scattering range of a beam in the electron emission device shown in FIG. 1 is calculated.

FIG. 5 is a schematic plan view of an embodiment of an electron source according to the present invention.

6 is a partially cutaway perspective view of an embodiment of an image forming apparatus according to the present invention using the electron source shown in FIG.

7 is a block diagram of the image forming apparatus shown in FIG.

8 is a schematic view of Example 1 of the method for manufacturing the electron-emitting device shown in FIG.

FIG. 9 is a schematic view of a second embodiment of a method for manufacturing an electron-emitting device according to the present invention.

10 is a structural diagram of an electron-emitting device manufactured by the method for manufacturing the electron-emitting device shown in FIG.

FIG. 11 is a structural diagram of a Spindt-type electron-emitting device.

FIG. 12 is a schematic view of a conventional surface conduction electron-emitting device.

FIG. 13 is a structural diagram of a field emission device disclosed in Japanese Patent Laid-Open No. 8-115654.

[Explanation of symbols]

101 Base 102 First Electrode Layer 103 Catalyst Material Layer 104 Insulating Layer 105 Second Electrode Layer 106 Electron Emitting Layer 107 Power Supply 108 Anode Electrode 109 High Voltage Power Supply 110 Ammeter 301 Equipotential Surface 302 Electron Beam Orbit 501 Base 502 X-direction Wiring 503 Y direction wiring 504 Electron emission element 505 Connection 601 Electron source substrate 602 X direction wiring 603 Y direction wiring 604 Electron emission part 605 Rear plate 606 Support frame 607 Glass substrate 608 Fluorescent film 609 Metal back 610 Face plate 611 High voltage terminal (Hv) 612 Envelope 701 Display panel 702 Scanning circuit 703 Control circuit 704 Shift register 705 Line memory 706 Synchronous signal separation circuit 707 Modulation signal generator 901 n ⁺ type Si substrate 902a First electrode layer 902b First electrode 903 Catalyst layer 9 04 insulating layer 905 second electrode 906 electron emitting layer 923 resist 1101 support 1102 cathode electrode 1103 insulating layer 1104 opening 1105 gate electrode 1106 electron emitting portion 1107 substrate 1108 phosphor layer 1109 anode electrode 1110 cathode panel 1111 anode panel 1201 substrate Reference numeral 1202 element positive electrode 1203 element negative electrode 1204 conductive thin film 1205 conductive thin film 1206 gap 1301 lower substrate 1302 cathode electrode 1303 gate electrode 1304 insulating layer 1305 thin film 1306 opening 1307 phosphor layer

Claims (16)

[Claims] 1. A first electrode and a second electrode having an opening are provided to face each other with an insulating layer having an opening communicating with the opening of the second electrode interposed therebetween, and the first electrode. An electron-emitting device that emits electrons by applying a voltage between an electrode and the second electrode, wherein an electron made of an electron-emitting substance is formed on the first electrode in the opening of the insulating layer. An electron-emitting device in which an emission layer is disposed, and a catalyst material and fibrous carbon grown through the catalyst material are used as the electron-emission layer. 2. A first electrode and a second electrode are provided so as to face each other with an insulating layer interposed therebetween, and minute holes penetrating the second electrode and the insulating layer are formed, and the minute hole is further formed. An electron emission layer made of an electron emission material is formed on a portion of the first electrode, and the first electrode and the second electrode are formed.
In the electron-emitting device configured such that electrons are emitted through the micropores by applying a voltage between the first and second electrodes, the uppermost end of the electron-emitting layer is located inside the micropores. An electron-emitting device that is present at a position lower than the lower end of the insulating layer of the electron-emitting device including an electrode, wherein the electron-emitting layer includes a catalyst substance and fibrous carbon grown through the catalyst substance. An electron-emitting device characterized by being used. 3. The electron-emitting device according to claim 1, wherein the second electrode is made of a material in which the fibrous carbon does not grow. 4. The insulating layer has a thickness of 500 nm, the second electrode has a thickness of 100 nm, and the micropores have a diameter of 50.
When the thickness of the electron emission layer is 0 nm and the thickness of the electron emission layer is 20 nm, the electron emission layer is present in a portion within 150 nm from the center of the micropore on the first electrode. 4. The electron-emitting device according to any one of 3 above. 5. A portion other than the micropores in the first electrode and the second electrode are covered with a material in which the fibrous carbon does not grow.
The electron-emitting device according to any one of 1. 6. The material of the electron emitting portion of the first electrode is made of a material in which fibrous carbon grows through the catalyst substance.
An electron-emitting device according to item. 7. The material in which the fibrous carbon does not grow is T
6. The electron-emitting device according to claim 3, wherein the electron-emitting device is made of at least one of a, Cr, Au, Ag, Pt, and the same type of material as the material forming the catalyst substance. 8. The electron-emitting device according to claim 6, wherein the material in which fibrous carbon grows through the catalyst substance is Ti, Zr, Nb oxide or oxide semiconductor. 9. The fibrous carbon is graphite nanofiber (GNF), carbon nanotube (CNT), which is obtained by decomposing and growing hydrocarbon gas using the catalyst substance.
9. Amorphous carbon (aC: H), diamond-like carbon (DLC), or any mixture thereof, according to any one of claims 1 to 8.
An electron-emitting device according to item. 10. The catalyst material is Pd, Ni, Fe,
10. The electron-emitting device according to claim 1, wherein the electron-emitting device is made of Co or any alloy thereof. 11. An electron source comprising a plurality of electron-emitting devices according to claim 1 arranged therein. 12. The electron source according to claim 11, wherein the low-potential supply wiring for driving the electron source and the high-potential supply wiring are configured in a matrix. 13. An electron source according to claim 11 or 12, and an image forming member for forming an image by the electrons emitted from the electron source, wherein each electron-emitting device of the electron source is provided with an information signal. An image forming apparatus characterized by controlling an electron emission amount. 14. The image forming apparatus according to claim 13, wherein the image forming member is a phosphor. 15. A step of forming a first electrode on a substrate, a part of the first electrode is removed, and a catalyst substance, which is a material for growing fibrous carbon, is embedded in the removed part. A step of forming an insulating layer on the first electrode, a step of forming a second electrode on the insulating layer, and forming micropores penetrating the second electrode and the insulating layer, respectively. And exposing the catalytic substance, which is a material for the growth of the fibrous carbon, and forming the fibrous carbon as an electron emission layer on the region of the catalytic substance of the first electrode. Method of manufacturing an emitting device. 16. A step of forming a first electrode layer of a material on which fibrous carbon grows via a catalyst substance on a substrate, and a catalyst layer of the catalyst substance is formed on the first electrode layer. A step of forming a layer of a material on which the fibrous carbon does not grow on the catalyst layer, a step of forming an insulating layer on the layer of a material on which the fibrous carbon does not grow, and a step of forming a first layer on the insulating layer. Forming a second electrode, and forming micropores penetrating the second electrode, the insulating layer, and a layer of a material on which the fibrous carbon does not grow, and exposing the catalyst substance in the micropore. A method of manufacturing an electron-emitting device, comprising: a step of forming the fibrous carbon as an electron-emitting layer on the exposed region of the catalytic material.