JP2002279888A - Field emission element, electron source and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a field emission element with high electron emission efficiency, an electron source composed of many field emission elements and an image display device composed of the electron source which can operate with low driving electric power. SOLUTION: The field emission element is composed of a pair of electrodes arranged opposed on a substrate, an electrically conductive film with a gap arranged between the electrodes and an electron emission portion formed in the vicinity of the gap. A magnetic film is arranged with magnetic field in the direction corresponding to the direction of extension of the gap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission device, an electron source having a large number of field emission devices, and an image display device using the electron source.

[0002]

The field emission device of the surface conduction type used in the Prior Art An image display apparatus, such as in JP-A 11-287862, JP-is described in detail. For example, FIG.
FIG. 1 is a cross-sectional view schematically showing a configuration example of a conventional flat field emission device. 8, a pair of electrodes (element electrodes) 2 and 3 are provided on the surface of a substrate 1, and a conductive film 4 is formed between the electrodes 2 and 3. A gap 5 is formed in the conductive film 4, and the vicinity of the gap 5 forms an electron emission section 6.

The electron emission from the electron emission portion 6 is caused by the strong electric field in the gap generated by the application of a voltage to the opposing device electrodes 2 and 3, and electrons from one of the conductive films of the electron emission portion are brought into vacuum by a tunnel effect. This is done by being released.

However, the emitted electrons travel along the electric field in the vicinity of the electron emitting portion, and most of the electrons are absorbed by the conductive film of the positive electrode facing the electron emitting portion. Only a part of the electrons attracted by the electric field of the anode (not shown) provided in the device becomes effective electron emission. Therefore, the effective electron emission efficiency is as low as about 0.1%, and increasing this has been a major issue. Also, an electron source having a plurality of such field emission devices, and an image display device including the electron source, have problems such as an increase in driving power and heat generation because the electron emission efficiency of the field emission devices is low. Yes,
There is a need for improvement.

[0005]

SUMMARY OF THE INVENTION The present invention has been made under the circumstances described above, and a field emission device having high electron emission efficiency, an electron source having a plurality of the field emission devices, and an electron source using the electron source. Provided is an image display device configured to be able to operate with low driving power.

[0006]

In order to solve the above-mentioned problems, the present invention provides a pair of electrodes disposed on a substrate so as to face each other, a conductive film formed between the electrodes and having a gap, A field emission device having an electron emission portion formed in the vicinity of the gap, wherein a magnetic film having a direction in which the gap extends in a magnetic field direction is disposed on the substrate. A field emission device is provided.

In the field emission device of the present invention, the magnetic film can have a granular structure in which magnetized ferromagnetic particles are dispersed in a non-magnetic material. In this case, the magnetic film is formed between the substrate and the electron-emitting portion,
An insulating magnetic film in which magnetized ferromagnetic particles are dispersed in a non-magnetic insulator can be obtained.

Further, the present invention includes a pair of electrodes arranged on a substrate so as to face each other, and a conductive film provided between the electrodes and having a gap, wherein the conductive film is Provided is a field emission device characterized by being magnetized in a direction in which a gap extends.

Further, the present invention provides an electron source comprising a plurality of the above-described field emission devices, and comprising means for applying an input electric signal to a pair of electrodes of the field emission device.

In this case, a plurality of field emission devices are arranged in a matrix, one electrode of each field emission device is connected to a row wiring, and the other electrode of each field emission device is orthogonal to the row wiring. Column wiring.

[0011] Furthermore, the present invention includes an electron source described above, by comprising image display means for displaying an image based on electrons emitted from the electron emission portion of each of the field emission device by the input electrical signal An image display device is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The present invention is characterized in that a magnetic member that generates a static magnetic field that causes a force directed to the anode to act on emitted electrons in the vicinity of the electron emitting portion is provided.

As shown in FIG. 2, when a static magnetic field acts on the flow of electrons, Lorentz force acts on the electrons. For this reason, in the present invention, in the gap between the conductive members, the flow of electrons from one side to the other is in a direction perpendicular to the direction and in a direction perpendicular to the direction in which the force is applied to the electrons, that is, in a direction in which the gap extends. A magnetic field is applied. That is, a magnetic member having such a direction as the direction of the magnetic field is arranged.

As described above, due to the transverse magnetic field orthogonal to the electron flow, the electrons emitted from the electron-emitting portion act to move away from the electron-emitting portion, and are attracted to the opposing conductive film in the gap. an increase in the proportion drawn to Meide anode,
The effective electron emission efficiency increases.

For example, the distance of the gap between the electron emitting portions is 10 n
m, and when a voltage of 10 V is applied, 1 Tesla (T)
In a transverse magnetic field of about 2 V / μ other than the electric field in the gap.
It is accelerated by a magnetic field equivalent to m. Due to this acceleration, electrons are easily attracted to the anode, and the number of electrons reaching the anode is increased. Effective electron emission efficiency is greatly improved from about 0.1% in the past to about 1%. .

In order to improve the effective electron emission efficiency, it is necessary to apply a magnetic field to the vicinity of the electron emitting portion because electrons move in a vacuum near the electron emitting portion. Since the electron emitting portion has a short size of about 100 nm or less, the magnetic material must be 1 nm to 1 nm in order to apply a magnetic field to the electron emitting portion.
It is desirable to use a so-called granular magnetic film which is small to about 00 nm, is dispersed in a non-magnetic material, leaks a magnetic field, and is magnetized in one axis direction. That is, it is desirable to apply such a stray magnetic field to the emitted electrons.

As an example of applying a magnetic field to the electron-emitting portion, the conductive film may be a magnetic film having a granular structure, and a magnetic field may be applied by the magnetic film. In this case, the magnetic film can be a conductive magnetic film in which fine ferromagnetic particles are dispersed in a nonmagnetic conductor made of a metal such as Al, Cu, Ti, Ta, and Nb.

Further, an electron emission portion can be provided on the insulating magnetic film having a granular structure provided on the substrate, and a magnetic field can be applied by the magnetic film. Insulating magnetic layer having a granular structure, silicon oxide, magnesium oxide, aluminum oxide, may be a structure in which are dispersed fine ferromagnetic particles in an insulating material such as silicon nitride.

The ferromagnetic material used is, for example, Co.
-Fe, Cr-Fe, Fe-Ni, Fe-Mn, Fe-
V, Fe-N, Fe-Nd-B, Sm-Co, Sm-F
e-Zr, Sm-Fe-Zr-N or the like, or Mn-Pt, Co-Pt, which is a magnetic alloy of a noble metal and a transition metal,
Co-Pd, Fe-Pd, Fe-Rh, Ni-Pd, N
i-Pt, Mn-Ir and the like can be mentioned.

With the field emission device of the present invention configured as described above, the electron emission efficiency can be greatly improved, and an electron source having a large number of such field emission devices is provided. According to the image forming apparatus configured by using the electron source, driving with low driving power is possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing one configuration example of the field emission device according to the first embodiment of the present invention. In FIG. 1, an insulating magnetic film 11 having a granular structure is formed on the surface of a substrate 1, and a pair of electrodes (element electrodes) 2 and 3 are provided on the magnetic film 11. A conductive film 4 is formed between the electrodes 2 and 3.
In the conductive film 4, a gap 5 extending in the vertical direction from the paper surface is formed, and the vicinity of the gap 5 constitutes an electron emission section 6.

The substrate 1 is usually made of glass or S
An i-substrate can be used. Examples of the glass include borosilicate glass and blue plate glass, and a glass substrate having a silicon oxide film or a silicon nitride film formed on the surface of such a glass is suitable.

The insulating magnetic film having a granular structure formed on the substrate 1 is formed by dispersing ferromagnetic particles in an insulating material.
Fe, Cr-Fe, Fe-Ni, Fe-Mn, Fe-
V, Fe-N, Fe-Nd-B, Sm-Co, Sm-F
e-Zr, Sm-Fe-Zr-N or the like, or Mn-Pt, Co-Pt, which is a magnetic alloy of a noble metal and a transition metal,
Co-Pd, Fe-Pd, Fe-Rh, Ni-Pd, N
i-Pt, Mn-Ir, or the like can be used.

The insulating magnetic film having a granular structure can be formed by, for example, a sputtering method. For example, using silicon oxide and a ferromagnetic material as a sputter target,
These by sputtering simultaneously or alternately, fine ferromagnetic particles in the silicon oxide film can be obtained dispersed insulating magnetic film. The thickness of the insulating magnetic film is usually 1
It is a ~1000nm, preferably 10~100nm. If the thickness of the magnetic film is too small, the magnetic field is insufficient to perform a desired action on the flow of electrons, and if it is too large, the effect is not so large. The size of the ferromagnetic particles is usually preferably 1/8 to 1/2 of the thickness of the magnetic film.

[0026] The size of the ferromagnetic particles in the silicon oxide, vinegar
Adjust the power, substrate temperature, substrate bias, etc.
And can be changed by For example, a table 1
Using a blue glass substrate with a silicon oxide film
Tsu SiO as data target _Two, And CoPt
No, RF sputtering power 2W / cm^Two, Substrate temperature 150
° C, substrate bias 0.2W / cm^TwoAnd sputter for 2 minutes
By doing so, CoPt particles having a particle size of 10 nm_Twofilm
20nm thick granular structure CoP dispersed in
t-SiO_TwoA magnetic film can be obtained.

Thereafter, the insulating magnetic film is magnetized in one axis direction. The magnetic flux density is, for example, about 1 Tesla, but since the magnetic film is set to be as thin as about 20 nm, the magnetic field is so weak that it cannot be detected at a distance of several cm from the substrate even after magnetization. This magnetic film may be a multilayer film such as a two-layer structure as necessary in consideration of adhesion, reliability, and the like.

A general conductor material can be used as a material for forming the device electrodes 2 and 3 which are disposed on the insulating magnetic film 11 so as to face each other. For example, Cr, Cu, I
r, Mo, Pd, Pt, Ti, Ta, W, metal or alloy and PdO of Zr or the like can be selected as appropriate SnO _2, RuO ₂ or the like oxide.

The distance L1 between the device electrodes 2 and 3 is usually several hundred nm in consideration of the voltage applied between the device electrodes 2 and 3.
Is set in a range of about to several tens μm. Also, the element electrodes 2 and 3
The length W (dimension in a direction perpendicular to the paper surface: not shown) is several μm to several hundred μm in consideration of the resistance value of the electrode and the electron emission characteristics.
m. The film thickness d of the device electrodes 2 and 3 is usually set in a range of several tens nm to several μm.

Conductive film 4 formed between device electrodes 2 and 3
Is formed by a droplet method, a vacuum deposition method, a printing method, etc.
The film thickness is normally formed to have a range of several Å~ several hundred nm.

The conductive film 4 may be a single layer or a multilayer structure such as a two-layer laminated structure made of two kinds of materials in consideration of reliability and the like. These materials are good electron emission characteristics, sufficient durability is determined in consideration of the ease of device manufacturing. Further, the film thickness of the conductive film 4 depends on the step coverage for the device electrodes 2 and 3 and the device electrodes 2 and 3.
Although it is appropriately set in consideration of the resistance value between them, it is usually preferable to set it in the range of several to several hundred nm.

As a specific material for forming the conductive film 4,
Is, for example, PdO, SnO_Two, In _TwoO_Three-Sb_TwoO_Three
Oxides such as Pd, Pt, Cr, Ti, Cu, Ta, W
Metal such as Si, semiconductor such as Si, carbon, etc.
They can be used in any combination. Note that the conductive film 4 and
The device electrodes 2 and 3 can be made of the same material.

The gap 5 formed in the conductive film 4 is
It is formed by fine processing technology such as forming by energization or focused ion beam technology. It is desirable to process the gap L2 between the gaps 5 so as to be 100 nm or less. If the distance L2 between the gaps 5 exceeds 100 nm, it becomes difficult to obtain highly efficient and uniform electron emission characteristics.

The electron emitting section 6 is usually subjected to an activation process described later in order to increase electron emission. Also,
Conductive fine particles having a particle size ranging from several Å to several tens of nm may be present inside the electron emitting portion 6. The conductive fine particles contain some or all of the elements of the material constituting the conductive film 4.

[0035] As a manufacturing method of a field emission device having the structure discussed above, there are various methods are described below with reference to FIG. 3 an example.

First, after sufficiently cleaning the substrate 1, FIG.
As shown in (a), the insulating magnetic body 11 is deposited by a sputtering method or the like. The insulating magnetic body 11, depending on the application, for example, is patterned using photolithography.

Next, after an element electrode material is deposited by a vacuum evaporation method, a sputtering method or the like, this is patterned by using, for example, a photolithography technique.
As shown in (b), the device electrodes 2 and 3 are formed on the substrate 1 on which the insulating magnetic material 11 is formed.

Next, a first metal, for example, Cr, is deposited on the substrate 1 on which the insulating magnetic material 11 and the device electrodes 2 and 3 are provided by a vacuum deposition method or the like to improve adhesion and to form a droplet. so that it does not spread, deposited to a thickness of 0.5nm.
Then, by patterning this metal film by lift-off or etching, as shown in FIG. 3 (c), to form the first conductive film 12.

Thereafter, as shown in FIG. 3D, an organic palladium liquid 13 is deposited on the first conductive film 12 by a droplet method, dried and fired, and as shown in FIG. , P
A second conductive film 14 made of dO is formed.

Subsequently, the device electrodes 2 and
3 by repeating the application of the pulse voltage between
As shown in (f), a gap 5 for forming an electron-emitting portion is formed.

Thereafter, a process called an activation step is performed. The activation step is a step of forming an electron-emitting portion in the gap 5 formed in the conductive films 12 and 14 and at least a part of the vicinity thereof in the following procedure.

In the activation step, for example, as shown in FIG. 4, an anode is arranged above and the device electrodes 2 and 2 are placed under vacuum.
It can be performed by repeating the application of the pulse between three. That is, a pulse is applied between the device electrodes 2 and 3 by a predetermined program, and the device current If and the emission current Ie are significantly increased, thereby forming an electron emission portion. The formation of the gap can be basically performed in the same manner in an inert atmosphere or under vacuum.

The end of the activation step is determined by determining the device current If.
And the emission current Ie. Note that the pulse width, pulse interval, pulse crest value, and the like are set as appropriate.

The field emission device obtained through the above steps is preferably subjected to a stabilization step. This step is a step of exhausting the organic substance in the vacuum container. It is preferable to use a vacuum exhaust device that does not use oil so that the oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum exhaust device such as a sorption pump or an ion pump can be used.

In the above-described activation step, when an oil diffusion pump or a rotary pump is used as an exhaust device and an organic gas derived from an oil component generated therefrom is used, it is necessary to keep the partial pressure of this component as low as possible. is there. The partial pressure of the organic component in the vacuum vessel is preferably 1 × 10 ⁻⁸ Torr or less, more preferably 1 × 10 ⁻¹⁰ Torr or less, at a partial pressure at which the carbon or carbon compound is not newly deposited.

Further, when evacuating the vacuum chamber,
It is preferable that the entire vacuum vessel is heated so that the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the field emission element are easily exhausted. The heating condition at this time is desirably a treatment at 80 to 250 ° C., preferably 150 to 250 ° C. for as long as possible. However, the present invention is not particularly limited to this condition, and the size and shape of the vacuum vessel, the field emission device This is performed under conditions appropriately selected according to various conditions such as the structure of the above. It is desirable that the pressure in the vacuum vessel be as low as possible, and 1 × 10 ⁻⁷ Torr
Or less, more preferably 1 × 10 ⁻⁸ Torr or less. Further, when the magnetic material is re-magnetized in the insulating magnetic film having the granular structure, the emission current becomes more stable.

[0047] after the stabilization process, the atmosphere at the time of driving, it is preferable to maintain the atmosphere during the stabilization process is completed, is not limited to this, if the organic material long as it is sufficiently removed Even if the pressure itself increases somewhat, it is possible to maintain sufficiently stable characteristics. By adopting such a vacuum atmosphere, deposition of new carbon or a carbon compound can be suppressed, and as a result, the device current If and the emission current Ie are stabilized.

The above-described field emission device according to the present embodiment, the electron emission efficiency of about 1%, compared with the conventional, showed electron emission efficiency was significantly improved.

FIG. 5 is a schematic view showing one configuration example of a field emission device according to the second embodiment of the present invention. This embodiment is an example in which a magnetic material is used for a conductive film. In FIG. 5, a pair of electrodes (element electrodes) 2 and 3
Is provided between the device electrodes 2 and 3, the conductive magnetic film 41 having a granular structure is formed.
A gap 5 is formed in the conductive magnetic film 41, and the vicinity of the gap 5 constitutes an electron emission section 6.

The materials constituting the substrate 1 and the device electrodes 2 and 3 are the same as those in the first embodiment.

The conductive magnetic film 41 is composed of a single layer or a multilayer, and the material thereof is determined in consideration of good electron emission characteristics, sufficient durability, simplicity of element fabrication, and the like. The thickness of the conductive magnetic film is appropriately set in consideration of the step coverage of the device electrodes 2 and 3, the resistance between the device electrodes 2 and 3, and the like. It is preferable to set it in the range.

When the conductive magnetic film 4 is formed of a two-layered film, the first layer may be made of Cr, Ti, Cu, Ta,
A conductive film such as Mo or W can be used, and a conductive magnetic film having a granular structure can be used as the second layer. Conductive magnetic film having a granular structure, Al, Cu, Ti, Nb,
It has a structure in which fine ferromagnetic particles are dispersed in a metal such as Ta. As the ferromagnetic material, for example, Co-Fe, Cr-
Fe, Fe-Ni, Fe-Mn, Fe-V, Fe-N,
Fe-Nd-B, Sm-Co, Sm-Fe-Zr, Sm
-Mn-Pt, Co-Pt, Co-Pd, F-Zr-N or the like or a magnetic alloy of a noble metal and a transition metal
e-Pd, Fe-Rh, Ni-Pd, Ni-Pt, Mn
-Ir or the like can be used.

The conductive magnetic film having a granular structure can be formed by, for example, a sputtering method. For example, a conductive magnetic film in which fine ferromagnetic particles are dispersed in a metal film can be obtained by using the above metal and a ferromagnetic material as a sputter target and sputtering them simultaneously or alternately.

The size of the ferromagnetic particles in the metal can be changed by adjusting sputtering power, substrate temperature, substrate bias, and the like. For example, a blue plate glass substrate having a silicon oxide film formed on the surface is used as the substrate 1, and Cu is used as a sputtering target. And PdFe by sputtering at an RF sputtering power of 2 W / cm ² , a substrate temperature of 150 ° C., and a substrate bias of 0.2 W / cm ² for 0.5 minute to obtain a granular structure PdFe—Cu having a thickness of 5 nm. A magnetic film can be obtained.

Thereafter, the magnetic film is magnetized in one axis direction. However, since the magnetic film is set to be as thin as about 5 nm, the magnetic field is so weak that it cannot be detected at a distance of several cm from the substrate even after magnetization. is there.

The method of forming the gaps 5 in the conductive magnetic film 41, the interval L2 between the gaps 5, the procedure for activating the electron emission section 6, and the like are the same as in the first embodiment.

There are various methods for manufacturing the above-mentioned field emission device, and one example will be described below with reference to FIG.

First, after sufficiently cleaning the substrate 1, a device electrode material is deposited by a vacuum evaporation method, a sputtering method, or the like, and then, for example, by photolithography, as shown in FIG. forming the device electrodes 2 and 3 on the 1.

[0059] Then, on the substrate 1 provided with the device electrodes 2 and 3, the first conductive film 51 and the granular structure magnetic film 52 is deposited by vacuum evaporation or sputtering, lift-off, these by etching or the like Patterning,
By magnetizing, as shown in FIG. 6B, a conductive magnetic film 41 is formed.

Next, a step of forming a gap for forming an electron-emitting portion, an activation step, and a stabilization step are performed. These steps can be performed in the same procedure as in the first embodiment. .

As described above, similarly to the first embodiment,
Electron emission efficiency can be obtained an improved field emission device. That is, the field emission device according to the present embodiment has an electron emission efficiency of about 1%, which is significantly improved as compared with the related art.

An electron source can be constructed by arranging a plurality of the field emission devices described above. Less than,
An electron source in which a plurality of field emission devices are arranged will be described.

Various arrangements of the field emission devices can be adopted. As an example, a plurality of field emission devices are arranged in a matrix in the X direction and the Y direction, and one of the electrodes of the plurality of field emission devices arranged in the same row is commonly connected to a wiring in the X direction, and the same column is connected. In which the other of the electrodes of the plurality of field emission devices disposed in common is connected to the wiring in the Y direction in common. This arrangement is a so-called simple matrix configuration. First, the simple matrix arrangement will be described in detail below.

As described above, the field emission device of the present invention
It has three characteristics. That is, when the electrons emitted from the field emission element are equal to or higher than the threshold voltage, the electrons can be controlled by the peak value and the width of the pulse voltage applied between the opposing element electrodes. On the other hand, the threshold voltage or less, most electrons are not emitted. According to this characteristic, even in case of disposing a plurality of field emission devices, it is appropriately applying a pulse-like voltage to each element,
In response to an input signal, it is possible to control the amount of electron emission by selecting the field emission device.

Hereinafter, based on this principle, an electron source substrate obtained by arranging a plurality of field emission devices of the present invention will be described with reference to FIG. In FIG. 7, the electron source substrate 61
Above, a number of field emission elements 64 are arranged in a matrix. Reference numeral 62 denotes an X-direction wiring, 63
Denotes a Y-direction wiring, and 65 denotes a connection.

The m X-direction wirings 62 are Dx1, Dx
2, ..., consists Dxm, vacuum evaporation method, printing method, it can be composed of a formed conductive metal or the like by sputtering or the like. The material, thickness, and width of the wiring can be appropriately selected. The Y-direction wiring 63 includes Dy1, Dy2,.
... consists of n wirings of Dyn, are formed in the same manner as X-direction wiring 62. An interlayer insulating layer (not shown) is provided between the m X-directional wirings 62 and the n Y-directional wirings 63 to electrically separate them.

The interlayer insulating layer is formed by vacuum evaporation, printing, spa
SiO formed using the sputtering method _TwoEtc.
Can be done. The interlayer insulating layer forms the X-direction wiring 62, for example.
The substrate 61 is formed in a desired shape on the entire surface or a part thereof.
In particular, at the intersection of the X-direction wiring 62 and the Y-direction wiring 63
As it can withstand potential differences, selecting the film thickness, material, manufacturing method is appropriately
Is done. The X-direction wiring 62 and the Y-direction wiring 63 are respectively
It is drawn out as an external terminal.

A pair of device electrodes (not shown) constituting the field emission device 64 have m X-direction wirings 62 and n
The Y-directional wires 63, connection 65 made of conductive metal or the like
Are electrically connected by

The material forming the wiring 62 and the wiring 63, the material forming the connection 65, and the material forming the pair of element electrodes may have the same or some of the constituent elements that are the same or different from each other. Good. These materials are appropriately selected, for example, from the above-described materials for the device electrodes. When the material forming the element electrode is the same as the wiring material, the wiring connected to the element electrode can also be called an element electrode.

[0070] in the X-direction wiring 62, X-direction scanning signal applying means 66 for applying a scanning signal for selecting a row of the field emission device 64 arranged in the X direction are connected. On the other hand, the Y direction wiring 63 is connected to a modulation signal generating means 67 and a Y direction scanning means 68 for modulating each column of the field emission elements 64 arranged in the Y direction according to an input signal. The driving voltage applied to each field emission device is supplied as a difference voltage between a scanning signal and a modulation signal applied to the device.

[0071] Using the constructed simple matrix wiring as described above, to select each of the devices can be drivable independently.

Next, an image forming apparatus constructed using such an electron source having a simple matrix arrangement will be described with reference to FIG. FIG. 8 is a schematic diagram illustrating an example of a display panel of the image forming apparatus.

In FIG. 8, an insulating magnetic film 72 is formed on an electron source substrate 71 also serving as a rear plate, and a plurality of field emission devices 73 are arranged on the insulating magnetic film 72. there. The field emission device 73 is insulating magnetic body 72
Because it is formed in the upper, by the action of electric and magnetic fields,
The electrons emitted in the vacuum are effectively attracted to the fluorescent film 75 as the anode.

Reference numeral 74 denotes a face plate having a fluorescent film 75 and a metal pack 76 formed on the inner surface of a glass substrate. The face plate 74 includes a fluorescent film 75 that generates light in response to an electron beam to form an image, and a high-voltage terminal 77 that applies a voltage to attract the electron beam. Reference numeral 78 indicates a support frame, and a rear plate 71 and a face plate 74 are connected to the support frame 78 using frit glass or the like. For example, by baking in a temperature range of 400 to 500 ° C. for 10 minutes or more in the air or nitrogen, the rear plate 71 and the face plate 74 are sealed and connected to the support frame 78 to form a display panel.

Reference numerals 79 and 80 denote an X-direction wiring connected to a pair of device electrodes of the surface conduction type field emission device and a Y-direction wiring.
It indicates the direction wirings, respectively.

The envelope is constituted by the face plate 74, the support frame 78, the rear plate 71 and the like. By providing a support 81 called a spacer between the face plate 74 and the rear plate 71, an envelope having sufficient strength against atmospheric pressure can be formed.

The fluorescent film 75 can be composed of only a phosphor in the case of monochrome. In the case of color display,
Depending on the arrangement of the phosphors, the phosphor film 75 can be composed of a black conductor called a black stripe or a black matrix and the phosphors. The purpose of providing the black stripes and the black matrix is to make the color separation and the like inconspicuous by making the painted portions between the phosphor films 75 of the necessary three primary color phosphors black in the case of color display. An object of the present invention is to suppress a decrease in contrast due to reflection of external light.

A metal pack 76 is usually provided on the inner side of the fluorescent film 75. The purpose of providing the metal pack 76 is to improve the luminance by mirror-reflecting the light emitted from the phosphor toward the inner surface side to the face plate 74 side, and to provide a high voltage terminal 77 as an electrode for applying an electron beam acceleration voltage. And protecting the phosphor from damage due to collision of negative ions generated in the envelope. The metal pack 76 performs a smoothing process (usually called “filming”) on the inner surface of the fluorescent film after the fluorescent film 75 is formed, and then deposits Al using vacuum evaporation or the like. Can be made.

When performing the above-described sealing by baking, in the case of color display, it is necessary to make the phosphors of each color correspond to the field emission elements. Therefore, sufficient alignment is required so that displacement does not occur even at a high temperature. It is desirable to carry out.

According to the image display device configured as described above, since the electron-emitting device having good electron emission efficiency is used, an image is displayed with low driving power and without generating much heat. It is possible.

[0081]

As described in detail above, according to the field emission device of the present invention, since the magnetic member for applying a static magnetic field to the emitted electrons is arranged near the electron emitting portion, the electron emission efficiency is improved. it can be greatly improved. In addition, according to an electron source including a large number of such field emission elements and an image display device configured using such an electron source, driving with low driving power is possible.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a field emission device according to one embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a force acting on emitted electrons.

FIG. 3 is a cross-sectional view illustrating a method of manufacturing the field emission device according to one embodiment of the present invention in the order of steps.

Figure 4 is a schematic view illustrating a gap portion and activation of process of the field emission device.

FIG. 5 is a cross-sectional view schematically showing a field emission device according to another embodiment of the present invention.

FIG. 6 is a sectional view illustrating a method of manufacturing a field emission device according to another embodiment of the present invention in the order of steps.

FIG. 7 is a diagram for explaining an example of an electron source according to the present invention and an outline of a driving method.

FIG. 8 is a schematic view showing an example of an image display device according to the present invention.

FIG. 9 is a sectional view schematically showing an example of a conventional field emission device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2, 3 ... electrode, 4 ... conductive film, 5 ... gap part,
Reference numeral 6: electron emitting portion, 11: insulating magnetic film, 12: first conductive film, 13: organic metal, 14: second conductive film, 41
... conductive magnetic film, 51 ... first conductive film, 52 ... conductive magnetic film, 61 ... electron source substrate, 62 ... x direction wiring, 63 ...
Y-direction wiring, 64: Field emission device, 65: Connection, 66 ...
x direction scanning signal applying means, 67... modulation signal generating means, 6
8 ... Y-direction scanning signal applying means, 71 ... Electron source substrate, 72
... insulating magnetic film, 73 ... electron-emitting device, 74 ... face plate, 75 ... fluorescent film, 76 ... Metal packs, 77 ...
High voltage terminal, 78: support frame, 79: wiring in x direction, 80: y
Direction wiring, 81 ... Support.

Claims (7)

[Claims] 1. A semiconductor device comprising: a pair of electrodes opposed to each other on a substrate; a conductive film provided between the electrodes and having a gap; and an electron-emitting portion formed near the gap. A field emission device, wherein a magnetic film whose magnetic field extends in a direction in which the gap extends is disposed on the substrate. 2. The magnetic film according to claim 1, wherein said magnetic film is formed between said substrate and said electron-emitting portion, and magnetized ferromagnetic particles are dispersed in a non-magnetic insulator. 2. The field emission device according to 1. A pair of electrodes 3. A arranged opposite to the substrate, is provided between the electrodes, and a conductive film having a gap section, the conductive film is in a direction in which the gap extends A field emission device characterized by being magnetized. 4. The field emission device according to claim 1, wherein the magnetic film has a granular structure in which ferromagnetic particles magnetized in a non-magnetic material are dispersed. 5. An electron source, comprising: a plurality of the field emission devices according to claim 1; and means for applying an input electric signal to a pair of electrodes of the field emission device. 6. A plurality of field emission devices are arranged in a matrix, one electrode of each field emission device is connected to a row wiring, and the other electrode of each field emission device is connected to the row wiring. The electron source according to claim 5, wherein the electron source is connected to a column wiring orthogonal to the column wiring. 7. An electron source according to claim 5, further comprising: image display means for displaying an image based on emission of electrons from an electron emission portion of each field emission device according to the input electric signal. An image display device characterized by the above-mentioned.