JP2001176379A - Electron emission element, electon source and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emission element, electron source and an image forming device that has improved electron emission efficiency and are capable of reducing the size of electron beams. SOLUTION: This element comprises an insulating substrate 1, a first electrode 2 which is formed on the substrate 1 and which constitutes an electrode emitting electrons, an insulation layer 3 formed on the substrate 1, a second electrode 4 which is formed on the insulation layer 3 and which does not contact with the first electrode 2, and a third electrode 5 to which a lower voltage is applied than the voltage applied to the first electrode 2 and which does not contact with the first electrode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electron-emitting device, an electron source, and an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a thermionic electron source and a cold cathode electron source, are known. The cold cathode electron source includes a field emission type (hereinafter, referred to as FE type), a metal / insulating layer / metal type (hereinafter, referred to as MIM type), and a surface conduction type electron emission element.

As an example of the FE type, WPDyke & W.W.Dola
n, “Field Emission”, Advance in Electoron Physics,
8,89 (1956) or CASpindt, “PHYSICAL Propertie
s of thin-film field emission cathodes with molybd
enium cones ", J. Appl. Phys., 47, 5248 (1976).

As an example of the MIM type, a report by Mead (CAM
ead, J. Appl. Phys., 32, 646 (1961)) are known.

As an example of a surface conduction electron-emitting device, a report by Elinson (MI Elinson RadioEng. Electron Phy
s., 10 (1965)).

[0006] The surface conduction electron-emitting device utilizes a phenomenon in which electrons are emitted by passing a current through a small-area film formed on a substrate in parallel with the film surface.

As the surface conduction electron-emitting device, one using an SnO ₂ film described in the above-mentioned report of Elinson, one using an Au thin film (G. Dittmer. Thin Solid Films,
9,317 (1972)), by ln ₂ 0 ₃ / SnO ₂ carrying film (M.Har
twell and CGFonstad, IEEETrans.ED Conf., 519 (197
5)), using carbon film (Araki et al., Vacuum, No. 26)
Vol. 1, No. 22 (1983)).

[0008] In these surface conduction electron-emitting devices, it is common to form an electron-emitting portion in a conductive film beforehand by performing an energization process called energization forming before emitting electrons.

That is, the energization forming is to apply and apply a voltage to both ends of the conductive thin film to locally destroy, deform or alter the conductive thin film, thereby forming an electron emission portion having a high electrical resistance state. That is.

In the electron emitting portion, an interval is generated in a part of the conductive film, and the electron is emitted from around the interval.

Conventionally, as an example in which a large number of surface conduction electron-emitting devices are arrayed, surface conduction electron-emitting devices are arranged in parallel, and both ends (both device electrodes) of each surface conduction electron-emitting device are wired. (Common wiring), an electron source in which a number of rows each connected by a common line are arranged (ladder-like arrangement) (for example, JP-A-64-31332, JP-A-1-293)
749, JP-A-2-257552).

In particular, in the case of a display device, a flat panel display device equivalent to a display device using liquid crystal can be provided, and a self-luminous display device which does not require a backlight is used as a surface conduction electron emission device. There has been proposed a display device in which an electron source in which a number of elements are arranged and a phosphor that emits visible light when irradiated with an electron beam from the electron source are combined (US Pat. No. 5,066,893).

[0013]

However, in the case of the above-mentioned prior art, the following problems have arisen.

There are various problems in using the conventional electron-emitting device as a high-performance image forming apparatus. In particular, in order to form a high-definition image forming apparatus, it is necessary to reduce the size of the electron-emitting device and to secure an electron emission amount for one pixel.

Therefore, it is desired that the electron emission efficiency (hereinafter, simply referred to as efficiency) of the electron emission element is as high as possible. In general, the electron beam has a spread, and in order to reduce the pixel size, it is necessary to adjust the trajectory of the electron beam and converge the electrons.

For example, in the case of a 14-inch VGA standard as an image forming apparatus, the pixel pitch is about 148 μm,
In the case of the SXGA standard of inches, the pixel pitch is 100
μm is required.

However, the relationship between reducing the size of the electron beam and increasing the efficiency is generally a trade-off relationship.

Normally, the FE type has a structure in which a voltage is applied to a gate electrode disposed in an opening to take out electrons from the tip of an electron-emitting device, and although the efficiency is high, the electron beam spreads radially, so that the image forming apparatus In this case, the spread becomes large.

On the other hand, the MIM type has a structure in which an insulator is arranged between a lower electrode and an upper electrode, and a voltage is applied between both electrodes to extract electrons. The beam size can be reduced because the directions are the same and there is no potential distortion in a vacuum, but the efficiency is generally poor because electrons are scattered between the insulating layer and the upper electrode.

In order to converge the electron beam, an electrode having another potential called a grid electrode is arranged above the electron emitting portion. In this case, there is a problem that the configuration becomes complicated.

On the other hand, there has been proposed a structure in which another electrode having another potential is arranged near the emitting portion of the electron-emitting device.

This structure is effective for reducing the beam size of the electron-emitting device. However, the addition of the convergence structure increases the pixel size in an image forming apparatus and complicates the device manufacturing method. Problem.

Here, a conventional surface conduction electron-emitting device will be described with reference to FIG. FIG. 18 shows a structural diagram of a conventional surface conduction electron-emitting device.

In FIG. 18, 311 is a substrate, 312 and 313 are electrodes, 314 is a conductive film, and 315 is an interval. 18A is a sectional view of FIG. 18A, and FIG. 18B is a plan view of FIG.

In a surface conduction electron-emitting device, there is generally a trade-off between efficiency and beam convergence.
As individual solutions of the prior art, there are a proposal for high efficiency (Japanese Patent Laid-Open No. 9-82214) and a proposal for beam convergence (Japanese Patent Laid-Open No. 2-112125).

Further, among the surface conduction electron-emitting devices, there is a so-called vertical type in which opposing electrodes are formed in a stepped form with an insulating layer interposed therebetween.

Even in the case of a surface conduction type device, a structure having another potential near the emitting portion of the device is effective. Here, a proposal for improving efficiency disclosed in Japanese Patent Application Laid-Open No. 9-82214 will be described with reference to FIG. FIG. 20 shows a structural view of a conventional electron-emitting device.

In FIG. 20, 311 is a substrate, 312 and 313 are electrodes, 314 is a conductive film, 315 is an interval,
17 is a correction electrode.

It is disclosed that this configuration can be expected to improve efficiency by applying an appropriate voltage to the correction electrode 317 placed near the electron-emitting device.

Further, in this configuration, it is disclosed that the position of the electron beam moves depending on the potential of the correction electrode 317. However, in this configuration, the size of one pixel is increased, and it is difficult to perform high-definition display.

The present invention has been made in view of the above circumstances,
An object of the present invention is to provide an electron-emitting device, an electron source, and an image forming apparatus that have good electron emission efficiency and can reduce the size of an electron beam.

Another object of the present invention is to provide an image forming apparatus capable of reducing the size of an electron beam and forming a high-definition image.

[0033]

In order to achieve the above object, an electron-emitting device according to the present invention comprises an insulating substrate, a first electrode layer formed on the substrate, An insulating layer to be formed; a second electrode layer formed on the insulating layer and not in contact with the first electrode layer; and a second electrode layer formed on the substrate and formed on the first electrode layer. A third electrode layer to which a voltage lower than the applied voltage is applied, the third electrode layer being in non-contact with the first electrode layer; and a first conductive layer provided on the first electrode layer and capable of emitting electrons. And a second conductive portion provided on the second electrode layer with a gap from the first conductive portion and capable of emitting electrons.

Also, an insulating substrate, a first electrode layer capable of emitting electrons, formed on the substrate, an insulating layer formed on the substrate, and formed on the insulating layer A second electrode layer capable of emitting electrons, formed with a gap with the first electrode layer; and a voltage formed on the substrate and applied to the first electrode layer. And a non-contacting third electrode layer to which a lower voltage is applied.

Further, the gap is formed on a side wall of the insulating layer.

Further, the third electrode layer is disposed on the substrate at a position facing the first electrode layer via the insulating layer.

An anode electrode is provided at a distance H [m] from the substrate, and a driving voltage Vf [V] is applied between the first electrode layer and the second electrode layer. ,
When an anode voltage Va [V] is applied to the anode electrode, a width W1 of the second electrode layer in a direction from the first electrode layer to the third electrode layer is represented by π as a circular constant. The characteristic distance Xs represented by the following equation (1)
It is characterized by being smaller than 10 times. Xs = (H · Vf) / (π · Va) (1)

Further, an electron source according to the present invention includes a first electrode layer formed on an insulating substrate, an insulating layer formed on the substrate, and an electrode layer formed on the insulating layer. A second electrode layer not in contact with the first electrode layer, and a first electrode formed on the substrate and applied with a voltage lower than a voltage applied to the first electrode layer; A third electrode layer that is not in contact with the electrode layer, a first conductive portion provided on the first electrode layer and capable of emitting electrons, and a third conductive layer having a gap with the first conductive portion. A plurality of electron emission portions provided on the second electrode layer and including a second conductive portion capable of emitting electrons are formed on the insulating substrate.

Also, a first electrode layer capable of emitting electrons, formed on an insulating substrate, an insulating layer formed on the substrate, and formed on the insulating layer, 1
A second electrode layer formed to have a gap with the first electrode layer and capable of emitting electrons; and a second electrode layer formed on the substrate and having a voltage lower than a voltage applied to the first electrode layer. A plurality of electron-emitting portions provided with the applied first electrode layer and a non-contacting third electrode layer are formed on the insulating substrate.

Further, the gap is formed on a side wall of the insulating layer.

Further, the third electrode layer is arranged on the substrate at a position facing the first electrode layer via the insulating layer.

An anode electrode is provided at a distance H [m] from the substrate, and a driving voltage Vf [V] is applied between the first electrode layer and the second electrode layer. And the anode voltage Va is applied to the anode electrode.
When [V] is given, the width W1 of the second electrode layer in the direction from the first electrode layer to the third electrode layer is represented by the following equation (2), where π is a circle ratio. It is characterized by being smaller than 10 times the indicated feature distance Xs. Xs = (H · Vf) / (π · Va) (2)

Further, the electron emission portions are arranged in a matrix on the substrate, and the first emission portions of the individual electron emission portions are arranged in a matrix.
Are connected to row wirings, the second electrode layers of the individual electron-emitting portions are connected to column wirings orthogonal to the row wirings, and the third electrode layers of the individual electron-emitting portions are It is characterized in that it is connected to a row wiring different from the row wiring to which the first electrode layer is connected.

Further, the electron emission portions are arranged in a matrix on the substrate, and the first emission portions of the individual electron emission portions are arranged in a matrix.
Are connected to row wirings, the second electrode layers of the individual electron-emitting portions are connected to column wirings orthogonal to the row wirings, and the third electrode layers of the individual electron-emitting portions are It is characterized in that it is connected via a resistor to the same row wiring as the row wiring to which the first electrode layer is connected.

Further, the image forming apparatus according to the present invention includes an anode electrode arranged at a distance of H [m] from the insulating substrate, and the vicinity of the anode electrode is provided with an electron emitted from the electron source. An image forming member on which an image is formed by collision of an electron beam is disposed, and the image on the image forming member is applied to the third electrode layer of the electron source such that the image is substantially immediately above the electron emitting portion. The potential of the applied voltage is adjusted.

Therefore, the electron-emitting device according to the present invention,
According to the electron source and the image forming apparatus, the electrons emitted from the first electrode layer, the second electrode layer, the first conductive portion, and the second conductive portion cause the potential of the third electrode layer to change. As a result, the trajectory is corrected, so that the convergence of the electrons can be improved and the spread of the electron beam can be suppressed.

Further, since the second electrode layer is formed on the insulating layer on the substrate, the electron emission efficiency can be improved, and as a result, the voltage applied to the third electrode layer can be kept low. be able to.

Further, a gap is provided between the first conductive part and the second conductive part and between the first electrode layer and the second electrode layer.
Further, since this gap is formed on the side wall of the insulating layer,
The electron emission efficiency can be further improved.

Further, the width W1 of the second electrode layer in the direction from the first electrode layer to the third electrode layer is represented by Xs = (H · Vf) / (π · Va), where π is a circle ratio. Is smaller than 10 times the feature distance Xs,
The electron emission efficiency can be improved, and the size of the formed pixel can be reduced.

Here, in the above description, the width W1 of the second electrode layer is smaller than 10 times the characteristic distance Xs, but the present invention is not limited to the case where it is smaller than 10 times. As long as the electron emission efficiency is improved, the width W1 of the second electrode layer may be, for example, 20 times or less or 5 times or less even if it is other than 10 times the characteristic distance Xs. Is also good.

[0051]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The materials, shapes, relative arrangements, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

In the following drawings, the same reference numerals are given to members described in the drawings used in the above description of the prior art and members similar to the members described in the drawings described above.

(Embodiment of Electron Emitting Element) A preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a structural view of one embodiment of an electron-emitting device according to the present invention, wherein FIG. 1 (a) is a sectional view and FIG. 1 (b) is a plan view. FIG. 2 shows a process chart of an example of a method for manufacturing the electron-emitting device shown in FIG.

In FIGS. 1 and 2, 1 is a substrate, 2 is a first electrode as a first electrode layer of the present invention, 3 is an insulating layer,
Is a second electrode as the second electrode layer of the present invention, 5 is a third electrode as the third electrode layer of the present invention, and 6 is a conductive electrode as the first conductive part and the second conductive part of the present invention. Membrane, 7 is the interval,
8 is an anode electrode, 9 is a power supply for applying a voltage to the first electrode 2 and the second electrode 4, 10 is a power supply for applying a voltage to the third electrode 5, and 11 is a power supply for applying a voltage to the anode electrode 8. It is.

One embodiment of the electron-emitting device according to the present invention is a surface conduction type electron in which electrons are emitted from a gap 7 by a voltage applied between a first electrode 2 and a second electrode 4 which are a pair of electrodes. A vertical surface conduction electron-emitting device in which an insulating layer 3 is stacked between a pair of electrodes and between the pair of electrodes.

Hereinafter, the structure of an embodiment of the electron-emitting device according to the present invention will be described with reference to the manufacturing method shown in FIG.

First, quartz glass, glass with reduced impurities such as Na, soda lime glass, soda lime glass, a Si substrate, etc., whose surface has been sufficiently cleaned beforehand, are deposited on a SiO ₂ substrate by sputtering or the like. A conductive film 21 is formed on an insulating substrate 1 made of ceramics such as alumina or the like.
Is formed (FIG. 2A).

Then, a resist pattern 22 is formed leaving a desired portion on the conductive film 21 (FIG. 2B), and the conductive film 21 is separated into the first electrode 2 and the third electrode 5. (FIG. 2C).

The first electrode 2 and the third electrode 5 are laminated by a general vacuum film forming technique such as a vapor deposition method and a sputtering method, and are formed by a photolithography technique.

As a material for the first electrode 2 and the third electrode 5, a general conductor material is used.
metals or alloys such as r, Au, Mo, W, Pt, Ti, Al, Cu, Pd and Pd, Au, RuO ₂ , Pd−
It is appropriately selected from a printed conductor composed of a metal such as Ag or a metal oxide and glass, a transparent conductor such as In ₂ O ₃ —SnO ₂ , and a semiconductor material such as polysilicon.

The thickness of each electrode is set in the range of several tens nm to several mm, and several tens nm to several hundred nm is set for electrode separation.

The electrode separation interval is set to be equal to or less than the width W1 of the insulating layer 3 and the second electrode 4 in a later step.

Further, an insulating layer 3 and a second electrode 4 are deposited (FIG. 2 (d)), and a resist pattern 23 aligned with the separated portion of the first electrode 2 and the third electrode 5 is formed (FIG. 2). 2 (e)), the insulating layer 3 along the resist pattern 23
And the second electrode 4 are formed (FIG. 2 (f)).

In this step, an etching method may be selected according to the material of each electrode and the insulating layer 3.

The insulating layer 3 is formed by a general vacuum film forming method such as a vapor deposition method and a sputtering method, a thermal oxidation method, an anodic oxidation method and the like. The material of the insulating layer 3 is preferably SiO ₂ , and a material having a high withstand voltage that can withstand a high electric field, such as other oxides and nitrides, is selected.

The thickness of the insulating layer 3 is from several nm to several tens μm.
, Preferably from several tens nm to several μm.
m.

The second electrode 4 may be made of the same material as the first electrode 3 and the third electrode 5 or a different material. The thickness of the second electrode 4 is set in the range of several nm to several μm, but is preferably thinner to improve electron emission efficiency.
m or less.

When the film thickness is small, a heat-resistant material is particularly desirable. The width W1 of the insulating layer 3 and the second electrode 4 is an important parameter for obtaining the effect of the present invention, and is designed according to driving conditions, element arrangement, and the like.
Xs, where Vf is the voltage between the first electrode 2 and the second electrode 4, Va is the potential applied to the anode electrode, and π is the pi.
= Feature distance Xs expressed by (H · Vf) / (π · Va)
It is better to be smaller than 10 times.

As described above, the first electrode 2, the second electrode 4, and the third electrode 5 are formed with the insulating layer 3 interposed. In the present embodiment, the electrodes are separated from each other via the insulating layer 3, and
When the electron-emitting device is viewed from above in a plan view, another configuration may be used as long as the second electrode 4 is configured to be sandwiched between the first electrode 2 and the third electrode 5.

Next, a step of forming a space 7 between the first electrode 2 and the second electrode 4 to form an electron emitting portion is performed.

For this purpose, a conductive film 6 is further selectively formed on one end face of the insulating layer 3 (FIG. 2 (g)).

The material of the conductive film 6 is Pd, Pt, Ru,
Ag, Au, Ti, In, Cu, Cr, Fe, Zn, S
metals such as n, Ta, W, Pb, Pt-Pd, Pd-Ag
Alloys such as PdO, SnO ₂ , In ₂ O ₃ , PbO, Sb ₂
Oxide such as O ₃ , boride such as HfB ₂ , ZrB ₂ , LaB ₆ , carbide such as TiC, ZrC, SiC, WC, Ti
It is appropriately selected from nitrogen such as N, ZrN, and HfN, semiconductors such as Si and Ge, organic polymer materials, and carbon and carbon compounds such as amorphous carbon, graphite, and diamond-like carbon.

The thickness of the conductive film 6 ranges from several Å to several hundreds n.
m, but is designed with resistance and step coverage.

Further, a voltage is applied between the first electrode 2 and the second electrode 4 to perform a step called an energization forming step to form a gap 7 as a gap according to the present invention (FIG. 2 (h)). ).

In the energization forming, the applied voltage waveform is preferably a pulse waveform. The energizing forming is
It may be performed in a vacuum atmosphere as in the subsequent activation step.

At the end of the energization forming process, a current is measured by applying a voltage to the extent that the conductive film 6 is not broken during the pulse interval, and the resistance is detected, and the resistance becomes 1 MΩ or more. Is terminated at times.

The forming step is not limited to the energization forming but includes a process of forming a local high resistance state on the conductive film 6.

Further, the electron-emitting device manufactured as described above is placed in a vacuum container, and the device is evacuated to a vacuum atmosphere.
An activation and stabilization step may be performed.

The activation step is a step of remarkably changing the device current If and the emission current Ie to form a shape capable of emitting electrons at a low voltage. Is to deposit.

In the activation step, for example, an organic gas is introduced into a vacuum vessel from an organic gas supply source, and a voltage is applied to the first electrode 2 and the second electrode 4 in an atmosphere containing a gas of an organic substance. . The applied voltage waveform is repeatedly applied in a pulse waveform.

There are a method of continuously applying a pulse having a pulse crest value at a constant voltage, and a method of applying a voltage pulse while increasing the pulse crest value.

The preferred gas partial pressure of the organic substance when producing carbon varies depending on the form of the carbon, the shape of the vacuum vessel, the type of the organic substance, and the like, and is appropriately set depending on the case.

Suitable organic substances include aliphatic hydrocarbons of alkanes and alkenes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, and organic acids such as phenol, carboxylic acid and sulfonic acid. Specifically, a saturated hydrocarbon represented by CnH ₂ n + 2 such as methane, ethane, and propane; and a CnH such as ethylene and propylene
Unsaturated hydrocarbon expressed by a composition formula such as ₂ n, benzene,
Toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methylamine, ethylamine, phenol, formic acid,
Acetic acid, propionic acid and the like can be used.

Further, after the activation step, a process called a stabilization step is performed. In this step, the organic substance in the vacuum vessel is exhausted.
It is preferably 33 × 10 ⁻⁷ Pa or less, more preferably 133 × 10 ⁻⁷ Pa.
^-8 Pa or less is particularly preferred.

When the inside of the vacuum vessel is evacuated, a vacuum exhaust system using no oil such as a sorption pump or an ion pump is preferable so that oil or the like generated from the apparatus is mixed and does not affect the element characteristics.

Further, when the vacuum vessel is evacuated, it is preferable to heat the entire vacuum vessel so that the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device are easily evacuated.

The heating temperature at this time is from 80 ° C. to 200 ° C.
Is preferably 5 hours or more, but is not particularly limited to this condition, and is appropriately selected depending on the size and shape of the vacuum vessel, the configuration of the electron-emitting device, and the like.

Next, the operation of the electron-emitting device according to this embodiment will be described with reference to FIGS. 3, 4, and 5. FIG. FIG. 3 is a conceptual diagram illustrating a potential distribution and an electron beam trajectory in one embodiment of the electron-emitting device according to the present invention. FIG. 4 shows a part of one embodiment of the electron-emitting device according to the present invention. FIG. 5 shows a structural diagram, and FIG. 5 shows a graph for explaining the operation of one embodiment of the electron-emitting device according to the present invention.

For comparison, a conventional surface conduction electron-emitting device will be described with reference to the drawings. FIG. 18 shows a structure diagram of a conventional surface conduction electron-emitting device, and FIG.
FIG. 1 is a conceptual diagram showing a potential distribution and electron arrival positions of a conventional surface conduction electron-emitting device. 18A is a sectional view of FIG. 18A, and FIG. 18B is a plan view of FIG.

First, to explain the effect of improving the efficiency of the electron-emitting device in this embodiment, the efficiency of the conventional surface conduction electron-emitting device will be described.

18 and 19, 311 is a substrate, 312 and 313 are electrodes, 314 is a conductive film, 31
5 is an interval, and 316 is an anode electrode.

According to SID'98 Digest Okuda, et al, there is a gap 315 on the order of nm between the opposing electrodes,
When a drive voltage Vf is applied to this element, electrons are emitted (or injected through the substrate) from the tip of the low potential electrode to the opposing high potential electrode, and the electrons are isotropically scattered again at the tip of the high potential electrode. I know that. (Accordingly, assuming that electrons are emitted isotropically from the tip of the high-potential electrode, it is known that the experiments and the numerical calculation predictions are consistent with each other.)

Most of the electrons emitted from the low potential electrode are repeatedly elastically scattered (multiple scattering) on the high potential electrode, and electrons exceeding the characteristic distance Xs reach the anode electrode 316.

The characteristic distance Xs is expressed as follows: Xs = D / 2 ｛{1+ (2H２Vf / πVa ・ D) ^{2 21/2} ≒ (H ・ Vf) / (π ・ Va) (3) , H is the distance between the electron-emitting device and the anode electrode,
π is the pi, D is the interval width formed in the electron-emitting portion, Vf
Is the drive voltage, and Va is the voltage of the anode electrode.

The approximation of the second day of the above equation (3) is expressed by Vf / D
It is satisfied in the case of で は Va / H (it is sufficiently satisfied in the case of a normal surface conduction electron-emitting device).

As shown in FIG. 19, the characteristic distance Xs is, as shown in FIG. 19, the distance from the point of emission to the point where the surface at the same potential as the high potential electrode intersects the high potential electrode in the equipotential distribution appearing in vacuum. It is represented as

The electron emission efficiency is governed by the decrease in the number of electrons due to partial absorption by the high potential electrode due to multiple scattering before the electrons emitted from the interval exceed Xs. Although the ratio (scattering coefficient) β scattered by the collision of electrons of about several tens eV is not clear, it is estimated to be about 0.1 to 0.5 per one scattering.

Since β is 1 or less in such a scattering mechanism, it can be seen that the amount of electrons taken out in a vacuum decreases with a power as the number of scattering increases.

Therefore, in the conventional surface conduction electron-emitting device as shown in FIG. 18, the electrons emitted from the interval 315 at least once on the opposing high potential electrode in the Xs as shown in FIG. Many electrons scatter more than once,
The number of electrons that are taken into the high potential electrode and disappear is increased, and the electron emission efficiency is reduced.

From the above-described mechanism, it can be seen that the electron emission efficiency can be increased by suppressing the scattering of the emitted electrons.

On the other hand, the efficiency of the electron-emitting device in this embodiment will be described with reference to FIG.

The electron-emitting device of this embodiment shown in FIG. 3 has a configuration in which the first electrode 2, the insulating layer 3, and the second electrode 4 are stacked. Similarly to the conventional electron-emitting device, a driving voltage Vf for driving the device is provided between the first electrode 2 and the second electrode 4.
Is applied, and the element current If flows.

At this time, with the interval 7 interposed, the first
The conductive film 6a as the conductive portion and the first electrode 2 side serve as a low potential electrode, and similarly, the conductive film 6b as the second conductive portion and the second electrode 4 serve as a high potential electrode. ing.

As in the case of the above-described conventional surface-conduction electron-emitting device, electrons are emitted (or injected through the insulating layer 3) from the tip of the low-potential electrode to the opposing high-potential electrode, and the electrons are transferred to the tip of the high-potential electrode. After the electrons are isotropically scattered again,
Voltage Va applied between electron-emitting device and anode electrode 8
As a result, the electrons are pulled up by the anode electrode 8, the electrons are captured by the anode electrode 8, and the emission current Ie flows.

In this embodiment, the second electrode as the high potential electrode
With the configuration in which the electrode 4 is arranged on the anode side of the first electrode 2 as a low potential electrode, the electron emission efficiency can be improved.

Next, the number of times of scattering of the electron-emitting device in this embodiment will be described with reference to FIG. In the electron-emitting device according to the present embodiment, the emitted electrons also travel toward the anode electrode 8 after being scattered on the high potential electrode by the conductive film 6 b and the second electrode 4 formed on the high potential side from the interval 7.

However, the distance T1 to the top of the high potential electrode
Is short, electrons can escape from the region of the potential distribution dominated by the electric field between the high-potential electrode and the low-potential electrode near the electron-emitting device with a small number of scatterings.

Further, when the distance T1 from the interval 7 to the top of the high potential electrode is shorter than the scattering distance T2 of the electrons, the electrons can reach the upper part of the element without being scattered, and the electron emission efficiency is greatly improved. .

Here, the flight distance T2 of the scattered electrons is
It is estimated that the interval width D is about 200 times the maximum, and in this case, scattering of electrons can be suppressed under the condition that the distance of T1 is T1 <D × 200.

The thickness of the second electrode 4 as a desirable high-potential electrode is desirably as thin as possible from the viewpoint of efficiency. However, when the film thickness is small, the resistance becomes high, and the voltage applied to the vicinity of the element becomes low. , Due to parasitic resistance.

Further, when the film is thin, heat dissipation of heat generated in the element is poor, and when the material does not have heat resistance, the film retreats during driving. From the above viewpoint, the film thickness is set in the range of several nm to several hundred nm, and more preferably, several tens n.
m.

Therefore, in the present embodiment, the second electrode 4
And the insulating layer 3 are stacked, so that the high-potential electrode is disposed closer to the anode than the low-potential electrode, and T
1 can be reduced, and a highly efficient electron-emitting device can be configured.

Next, the shape of the electron beam according to the present embodiment will be explained. First, an electron beam of a conventional surface conduction electron-emitting device will be described.

FIG. 19 shows the arrival position of electrons in the conventional electron-emitting device. As shown in FIG. 19, in the related art, the beam largely shifts from the emission position when reaching the characteristic distance Xs in the upper part of the element, and largely shifts due to the distorted electric field in the upper part.

The beam diameter is almost equal to the amount of deviation from immediately above the emission part to the main arrival position of the beam. Therefore, the beam diameter is calculated from Ld ≒ 4KhH (Vf / Va) ^1/2 ·· (4) known to be written in Lw ≒ 2KwH (Vf / Va) 1/2 ·· (5).

Here, Lh is the longitudinal direction (Y direction) of the beam,
Lw indicates the size of the beam in the horizontal direction (X direction).

Kh and Kw may vary slightly depending on the element structure, but are in the range of 0.8 to 1.0, and can be approximated by 1 in most cases.

Next, the correction voltage Vc and the shaping of the beam shape in the electron-emitting device according to the present embodiment will be explained with reference to FIG.

First, let us consider a case where the potential of the third electrode 5 as a correction electrode is equipotential with the first electrode 2 and consider a beam in which no correction is performed. The state is shown by a broken line in FIG. Was.

In this case, the second electrode 4 as a high-potential electrode of the electron-emitting device has a potential configuration sandwiched between low-potential electrodes on both sides when viewed from above.

At this time, if the width W1 of the second electrode 4 as the high-potential electrode is sufficiently large, the electrons reach the anode electrode 8 in an electron trajectory substantially similar to that of the conventional electron-emitting device. As the width W1 of the second electrode 4 decreases, the characteristic distance Xs decreases.

Therefore, the main arrival position of the electron beam in the X direction cannot be described by Lw in the above-mentioned equation (5), and is shifted right above the emission part.

Further, when the width W1 is reduced, the equipotential surface having the same potential as the high potential does not cross the second electrode 4 as the high potential electrode, and the characteristic distance Xs cannot be defined.

In this state, the beam is affected by the low-potential electrodes on both sides of the high-potential electrode, and proceeds in a vacuum so that the beam is folded (reflected).

However, in the conventional electron-emitting device, the electron beam did not appear from directly above the emitting portion to the low potential side.

Therefore, the above equation (5) showing the beam shape of the conventional electron-emitting device expresses not only the shape but also the arrival position of the main beam itself.

On the other hand, when there is a low potential on both sides as in the electron-emitting device according to the present embodiment, the arrival position of the main beam shifts to just above the device. It also reaches in one direction in the axis.

Next, the operation of the third electrode 5 as a correction electrode in the present embodiment will be described with reference to FIGS. The present embodiment is characterized in that the third electrode 5 is provided, and the correction voltage Vc is applied to the third electrode 5.

The correction voltage Vc in the present embodiment is a voltage for correcting the electron arrival position, and is selected so as to move the electron arrival position almost immediately above the element.

FIG. 5A shows the relationship between the electron arrival position and the correction voltage Vc. Correction voltage V in this embodiment
c is when the first electrode 2 is used as a reference as a low potential electrode,
A potential lower than the voltage applied to the first electrode 2 is provided.

As a result, as shown in FIG. 3, the potential distribution is biased, and the arrival position of electrons changes.

FIG. 5B shows the relationship between the correction voltage Vc and the width W1 of the second electrode 4 as a high-potential electrode. As the width W1 of the second electrode 4 as the high-potential electrode is smaller, the electron arrival position can be moved with a smaller correction potential.

Here, in order to clarify the correction electrode of the present embodiment, a description will be given with reference to the prior art. Conventionally, in the surface-conduction type electron-emitting device, the one related to the function of the correction electrode has been disclosed in Japanese Patent Application Laid-Open No. 9-82214 as described above, and the configuration is shown in FIG. FIG. 20 shows a structural view of a conventional electron-emitting device.

In FIG. 20, components similar to those in FIG. 18 are denoted by similar reference numerals. That is, in FIG.
Is a correction electrode. 20A is a sectional view thereof, and FIG. 20B is a plan view thereof.

In FIG. 20, reference numeral 312 denotes a low potential side electrode, and 313 denotes a high potential side electrode. The elements include:
Vf is applied, and Vc is applied to the correction electrode 317. However, by applying a voltage Vc higher than Vf, the characteristic distance Xs appearing on the high-potential electrode 313 is shortened, thereby reducing the number of scatterings, It is a general function to increase the efficiency.

As other functions, a method of giving a potential lower than Vf to Vc to reduce the amount of electron emission and perform switching, and modulating the correction potential Vc together with the anode potential Va to modulate the beam position and burn the phosphor. There is disclosed a method for preventing the above.

On the other hand, also in this embodiment, in addition to a driving electrode for moving an electron beam, a correction electrode is provided near an electron emitting portion.

However, in the configuration of the prior art, when the arrival position of electrons is changed just above the element as desired by the low correction voltage Vc as in this embodiment, the total amount of emitted electrons is drastically reduced. In general, it could not be used.

Therefore, in the prior art, it is effective to apply a positive potential and use the correction electrode to increase the efficiency.

On the other hand, in the structure of the electron-emitting device according to the present embodiment, as described above, since the efficiency can be increased, even if the position where the electrons reach is changed by the correction potential Vc, the amount of emitted electrons is sufficient. It can be taken.

In particular, by sufficiently reducing the width W1 of the second electrode 4 as a high-potential electrode, the potential Vc of the correction electrode can be reduced.
Are not so far apart from the drive voltage of the element.

(Embodiment of Electron Source) Next, an embodiment of the electron source according to the present invention will be described with reference to FIGS. In FIG. 6, using the electron-emitting device shown in FIG.
FIG. 7 shows a wiring diagram of electron sources obtained by arranging a plurality of electron sources.
FIG. 2 shows a circuit diagram of an electron source obtained by arranging a plurality of electron emitters using the electron-emitting device shown in FIG.

The electron source shown in FIG. 6 is an electron source formed by arranging a plurality of embodiments of the electron-emitting device according to the present invention in an m × n matrix as an electron-emitting portion according to the present invention. Source.

In the X direction, m X direction wirings Dx1 and Dx are used as X direction wirings 61 as row wirings according to the present invention.
, Dxm are arranged, and m correction electrode wirings Dc1, Dc2,..., Dcm in the X direction are alternately arranged as the correction electrode wiring 62 as another row wiring according to the present invention.

In the Y direction, n Y direction wirings Dy1 as n Y direction wirings 63 as column wirings according to the present invention,
Dy2, Dy3,..., Dyn.

However, in the above description, m and n are arbitrary integers.

The first electrode, the second electrode, and the third electrode constituting the electron-emitting device have an X-direction wiring and a Y-direction wiring, respectively.
It is electrically connected to the correction electrode.

In the electron source of this embodiment, the above-described electron-emitting devices are generally arranged in a simple matrix arrangement. That is, a plurality of electrodes are arranged in a matrix in the X direction and the Y direction, one of the electrodes of the plurality of electron-emitting devices arranged in the same column is commonly connected to a wiring in the X direction, and a plurality of electrodes arranged in the same column. The other electrode of the electron-emitting device is commonly connected to a wiring in the Y direction.

The wiring of the correction electrode in the X direction is generally wired in the X direction separately from the wiring in the X direction.

Although arrangements other than the simple matrix arrangement can be adopted, the arrangement becomes more complicated and is difficult to realize in a high-definition image forming apparatus.

For example, connection is made at each end of a plurality of electron-emitting devices arranged in parallel, a large number of rows of electron-emitting devices are arranged (row direction), and in a direction orthogonal to the wiring (column direction),
Control electrode (grid electrode) placed above the electron-emitting device
There is also a ladder-like arrangement for controlling and driving electrons from the electron-emitting device.

The electron source shown in FIG. 7 shows an example in which a large number of the above-described electron-emitting devices are arranged in a simple matrix. In FIG. 7, the same members as those in FIG. 6 are indicated by the same reference numerals as described above.

In the X direction, a plurality of X direction wirings 61 and X direction correction electrode wirings 62 are alternately arranged, and in the Y direction, a plurality of Y direction wirings 63 are formed.

The X-direction wiring 61 and the X-direction correction electrode wiring 62 exist on the same plane, but are separated in a pattern shape. On the other hand, the X-direction wiring 61 and the X-direction correction electrode wiring 62 and the Y-direction wiring 63 are electrically separated from each other by an insulating layer.

The first, second, and third electrodes constituting the electron-emitting device are electrically connected to the X-direction wiring 61, the Y-direction wiring 62, and the correction electrode 63, respectively.

X direction wiring 61, X direction correction electrode wiring 6
The 2 and Y direction wiring 63 can be made of a conductive metal or the like formed by using a vacuum deposition method, a printing method, a sputtering method, or the like.

The material, thickness, and width of the wiring are appropriately designed.
In FIG. 7, in the electron-emitting device section 71, the Y-directional wiring is designed to have a width of W1 and the Y-directional wiring 63 is designed to be thick except in the vicinity of the electron-emitting device section 71.

The insulating layer may be the same as, for example, the insulating layer 3 between the first electrode 2 and the second electrode 4 of the electron-emitting device shown in FIG. 3, or may be provided separately therefrom. .

The insulating layer is made of SiO ₂ or the like formed by using a vacuum deposition method, a printing method, a sputtering method, or the like. The thickness and the shape are appropriately set so as to be able to withstand the potential difference at the intersection between the wires.

X direction wiring 61 and X direction correction electrode wiring 6
2 and the material forming the Y-direction wiring 63, and the first electrode 2, the second electrode 4 and the third electrode 5 shown in FIG. Each may be different.

These materials are appropriately selected, for example, from the above-mentioned materials for the device electrodes. If the material forming the first, second, and third electrodes is the same as the wiring material, it can be said that the wiring connected to the electrodes is also an electrode.

As for the electron convergence effect of the correction electrode wiring 62 in the X direction, the same effect as that described in the above-described embodiment of the electron-emitting device according to the present invention can be obtained.

In the present embodiment, electrons emitted from the electron-emitting device can be controlled by the peak value and the width of the pulse-like voltage applied between the electrodes when the electrons are below the threshold voltage.

On the other hand, when the voltage is lower than the threshold voltage, almost no light is emitted. According to this characteristic, even when a large number of electron-emitting devices are arranged, if a pulse-like voltage is appropriately applied to each of the devices, the electron-emitting device can be selected and the amount of electron emission can be controlled in accordance with an input signal. .

Therefore, in the above configuration, the electron source according to the present embodiment can select individual elements using simple matrix wiring and can be driven independently, and can perform low correction without lowering the efficiency of electron emission. The convergence of electrons can be enhanced by the voltage.

(Embodiment of Image Forming Apparatus) Next, an embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 8 is a perspective sectional view of an embodiment of the image forming apparatus according to the present invention. The image forming apparatus according to the present embodiment is an image forming apparatus using one embodiment of the above-described electron-emitting device according to the present invention.

In FIG. 8, reference numeral 81 denotes a substrate of an electron source on which a plurality of electron-emitting devices are arranged; 91, a rear plate on which the substrate 81 of the electron source is fixed; 96, an inner surface of a glass substrate 93; Is a face plate on which a fluorescent film 94 and a metal back 95 are formed.

Reference numeral 92 denotes a support frame. A rear plate 91 and a face plate 96 are connected to the support frame 92 using frit glass or the like.

The envelope (panel) 98 is composed of the face plate 96, the support frame 92, and the rear plate 91 as described above.

Since the rear plate 91 is provided mainly for the purpose of reinforcing the strength of the substrate 81, if the substrate 81 itself has sufficient strength, the separate rear plate 91 can be omitted, and The rear plate 91 may be an integral member.

The fluorescent film 94 of the support frame 92 and the metal back 9
5 is disposed on the inner surface thereof, frit glass is applied to an adhesive surface where the face plate 96, the rear plate 91, and the support frame 92 are joined, and the face plate 96, the support frame 92, and the rear plate 91 are moved to a predetermined position. , Fix, heat, bake and seal.

Further, various methods such as lamp heating using an infrared lamp or the like, a hot plate, and the like can be adopted as the heating and casting method for firing and sealing, but are not limited thereto.

Further, the bonding material for heating and bonding the plurality of members constituting the envelope 98 is not limited to frit glass, but may be any material that can form a sufficient vacuum atmosphere after the sealing step. An adhesive material can be employed.

The above-described envelope 98 is an example of an embodiment of the image forming apparatus according to the present invention, and the image forming apparatus according to the present invention is not limited to such an envelope, but may be variously modified. Can be adopted.

As another example, the support frame 92 is directly mounted on the substrate 81.
And the envelope 98 may be constituted by the face plate 96, the support frame 92, and the substrate 81.

By installing a support (not shown) called a spacer between the face plate 96 and the rear plate 91, an envelope 98 having sufficient strength against atmospheric pressure is formed. You can also.

Next, an example of the fluorescent film used in the image forming apparatus shown in FIG. 8 will be described with reference to FIGS. FIG. 9 shows a structural diagram of an example of a fluorescent film used in the image forming apparatus shown in FIG.

Further, as shown in FIG.
Can be composed only of the phosphor 85 in the case of monochrome.

In the case of the color fluorescent film 94, depending on the arrangement of the phosphors, a black conductive material 86 called a black stripe shown in FIG. 9A or a black matrix shown in FIG. And the body 85.

The purpose of providing the black stripes and the black matrix is to make the color separation between the phosphors 85 of the necessary three primary color phosphors black in the case of color display so that color mixing and the like become inconspicuous. The object of the present invention is to suppress a decrease in contrast caused by external light reflection at 94.

As the material for the black stripe, other than the commonly used material containing graphite as a main component, a material having conductivity and low transmission and reflection of light can be used.

As a method of applying the phosphor on the glass substrate 93, a precipitation method, a printing method or the like can be adopted regardless of monochrome or color.

On the inner surface side of the fluorescent film 94, a metal back 95 is usually provided. The purpose of providing the metal back 95 is to improve the luminance by mirror-reflecting the light toward the inner surface side of the phosphor emission toward the face plate 96 and to function as an electrode for applying an electron beam acceleration voltage. And protecting the phosphor 94 from damage due to collision of negative ions generated in the envelope.

After the phosphor film is formed, the metal back 95 is subjected to a smoothing treatment (usually “filming”) on the inner surface of the phosphor film.
Called. ) And then depositing Al using vacuum evaporation or the like.

The face plate 96 is further provided with a fluorescent film 9.
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 94 in order to increase the conductivity of No. 4.

Next, a vacuum sealing step of sealing the envelope (panel) 98 having been subjected to the sealing step shown in FIG. 8 will be described.

In the vacuum sealing step, the envelope (panel) 98 is heated and maintained at 80 to 250 ° C., and exhausted through an exhaust pipe (not shown) of an exhaust device such as an ion pump or a sorption pump. Then, after the atmosphere is made sufficiently low in organic substances, the exhaust pipe is heated with a burner to be dissolved and sealed.

In order to maintain the pressure after the envelope 98 is sealed, a getter process may be performed. This is because the getter arranged at a predetermined position (not shown) in the envelope 98 is heated by heating using resistance heating or high-frequency heating immediately before or after the envelope 98 is sealed. This is a process for forming a deposited film.

The getter is usually composed mainly of Ba or the like, and maintains the atmosphere in the envelope 98 by the adsorption action of the deposited film.

The image forming apparatus constituted by using the electron sources of the simple matrix arrangement manufactured by the above steps is as follows.
External terminals Dxl to Dxm, Dyl
By applying a voltage through Dyn, electron emission occurs.

The metal back 95 via the high voltage terminal 97,
Alternatively, a high voltage is applied to a transparent electrode (not shown) to accelerate the electron beam.

The accelerated electrons collide with the fluorescent film 94,
Light emission occurs to form an image.

Next, an example of a driving circuit for driving the image forming apparatus shown in FIG. 8 will be described with reference to FIG. FIG. 10 is a block diagram showing an example of a driving circuit for driving the image forming apparatus shown in FIG.

FIG. 10 is a block diagram of an example of a driving circuit for performing display in accordance with an NTSC television signal.

The drive circuit shown in FIG. 10 is provided with a switch 1302 having M switching elements (in the figure, structurally indicated by S1 to Sm).

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 1301.

Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 1303, and can be configured by combining switching elements such as FETs.

In the case of this example, the DC voltage source Vx is a drive applied to an element that is not scanned based on the characteristics (electron emission threshold voltage) of the above-described embodiment of the electron emission element according to the present invention. It is set so as to output a constant voltage such that the voltage is equal to or lower than the electron emission threshold voltage.

The control circuit 1303 has a function of matching the operation of each unit so that appropriate display is performed based on an image signal input from the outside.

The control circuit 1303 includes the synchronization signal separation circuit 1
Based on the synchronizing signal Tsync sent from 306, each control signal of Tscan, Tsft, and Tmry is generated for each unit.

The synchronizing signal separating circuit 1306 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and uses a general frequency separating (filter) circuit or the like. Can be configured.

The synchronization signal separated by the synchronization signal separation circuit 1306 is composed of a vertical synchronization signal and a horizontal synchronization signal, but is shown here as a Tsync signal for convenience of explanation.

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 1304.

The shift register 1304 is for serially / parallel-converting a serially input DATA signal for each line of an image, and operates based on a control signal Tsft sent from the control circuit 1303. (Ie, the control signal Tsft is transmitted to the shift register 13
04 shift clock. ).

The data for one line of the image subjected to the serial / parallel conversion (corresponding to the drive data for N electron-emitting devices) is output from the shift register 1304 as N parallel signals Id1 to Idn.

The line memory 1305 is a storage device for storing data for one line of an image for a required time, and stores the contents of Id1 to Idm as appropriate according to a control signal Tmry sent from the control circuit 1303.

The stored contents are I'd1 to I'dn
And output to the modulation signal generator 1307.

The modulation signal generator 1307 is a signal source for appropriately driving and modulating each of the electron-emitting devices according to the present invention in accordance with each of the image data I'd1 to I'dn. The voltage is applied to the electron-emitting devices of the present invention in the display panel 1301 through the terminals Doyl to Doyn.

Further, the terminals Doc1 to Docm are given a constant potential after being taken out. This potential may be DC or terminals Dox to Dox
The operation may be based on a control signal Tscan output from the control circuit 1303 given to m. In the figure, the case of DC is shown.

As described above, the electron-emitting device 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.
and electron emission occurs only when a voltage equal to or 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 device.
Therefore, when a pulse-like voltage is applied to the device, for example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur, but when a voltage higher than the electron emission threshold is applied. Outputs an electron beam.

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

Therefore, as a method of modulating the electron-emitting device in accordance with the input signal, a voltage modulation method, a pulse width modulation method, or the like can be employed. When performing the voltage modulation method, a circuit of the voltage modulation method that generates a voltage pulse of a fixed length and modulates the peak value of the pulse appropriately according to input data is used as the modulation signal generator 1307. be able to.

When implementing the pulse width modulation method,
As the modulation signal generator 1307, a pulse width modulation type circuit that generates a voltage pulse having a constant peak value and appropriately modulates the width of the voltage pulse according to input data can be used.

The shift register 1304 and the line memory 1
305 can be a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.

When the digital signal type is used, it is necessary to convert the output signal DAm of the synchronization signal separation circuit 1306 into a digital signal.
May be provided with an A / D converter.

In connection with this, the circuit used for the modulation signal generator 1307 is slightly different depending on whether the output signal of the line memory 1305 is a digital signal or an analog signal.

That is, in the case of the voltage modulation method using a digital signal, for example, a D / A conversion circuit is used as the modulation signal generator 1307, and an amplification circuit and the like are added as necessary.

In the case of the pulse width modulation method, the modulation signal generator 1307 includes, for example, a high-speed oscillator, a counter for counting the number of waves output from the oscillator, and a comparison between the output value of the counter and the output value of the memory. Comparator (comparator)
Is used.

If necessary, an amplifier for amplifying the pulse width modulated signal output from the comparator up to the drive voltage of the electron-emitting device of the present invention can be added.

In the case of the voltage modulation method using an analog signal, an amplification circuit using, for example, an operational amplifier or the like can be used as the modulation signal generator 1307, and a level shift circuit or the like can be added as necessary.

In the case of the pulse width modulation system, for example, a voltage controlled oscillator (VCO) can be employed, and an amplifier for amplifying the voltage up to the drive voltage of the electron-emitting device of the present invention can be added as necessary. Can also.

The configuration of the image forming apparatus described here is an example of an 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.

[0225] For example, the NTSC system is used for the input signal, but the input signal is not limited to this.
In addition to the PAL and SECAM methods, a TV signal (for example, a high-definition TV such as the MUSE method) including a larger number of scanning lines can be employed.

In addition to the display device, the present invention can also be used as an image forming device as an optical printer constituted by using a photosensitive drum or the like. As described above, also in the embodiment of the image forming apparatus according to the present embodiment, for the same reason as the above-described embodiment of the electron-emitting device according to the present invention, the electron emission efficiency is set to a practical range. And the convergence of electrons can be improved.

Therefore, an image forming apparatus capable of forming a high-definition image can be provided.

[0228]

The present invention will be described in more detail with reference to the following examples.

Example 1 A method of manufacturing an embodiment of the above-described electron-emitting device according to the present invention will be described with reference to FIGS. 1, 2 and 3, and an apparatus manufactured by this manufacturing method will be described. Example 1 is assumed. Hereinafter, the manufacturing process of the electron-emitting device of this embodiment will be described in detail.

(Step 1) Using quartz for the substrate 1 and thoroughly cleaning it, then forming a first electrode 2 having a thickness of 1 by a sputtering method.
Deposit 50 nm of Ta.

(Step 2) Thereafter, in a photolithography step, spin coating of a positive photoresist (AZ1500 / manufactured by Clariant), exposure and development of a photomask pattern, and development of a mask pattern (width 1.5 μm)
Was transcribed.

(Step 3) Thereafter, using the patterned photoresist as a mask, Ta is etched by dry etching.
Was completely removed. Thus, the first electrode 2 and the third electrode 5 were separated.

(Step 4) Thickness 1000 μm as insulating layer 3
When m SiO ₂ was deposited, the uppermost portion was almost flattened.

Thereafter, until the thickness reaches 100 nm, the Si
O ₂ was uniformly etched, and then 50 nm thick Ta was deposited thereon as the second electrode 4.

(Step 5) Thereafter, in a photolithography step, spin coating of a positive photoresist (AZ1500 / manufactured by Clariant), exposure and development of a photomask pattern were performed, and the mask pattern was transferred.

Thereafter, using the patterned photoresist as a mask, the insulating layer 3 and the upper electrode 4 are dry-etched using CF 4 gas, stopped at the lower electrode 2, and stopped at the width W.
A second electrode 4 having a length of 1 μm and a length L1 of 50 μm was formed.

(Step 6) Next, a 5 nm-thick Pt-Pd
Was deposited on one side of the high potential electrode.

At this time, the length L2 where Pt-Pd was deposited was 30 μm. The Pt-Pd conductive film 6 was selectively deposited by ion sputtering using a photolithography technique while masking one side of the high-potential electrode.

(Step 7) Next, a 15V pulse voltage (ON time: 1 msec / OF) is applied to the first electrode 2 and the second electrode 4.
F time: 9 msec) was applied, and electricity was supplied to the Pt-Pd conductive film 6 to form an interval 7 by a forming process. The forming was terminated when the resistance between the upper and lower electrodes became 10 MΩ.

(Step 8) Next, the element was placed in a vacuum vessel, and after evacuation, BN (penzonitrile), 266 ×
The same pulse voltage as in the forming step was applied to the first electrode 2 and the second electrode 4 in an atmosphere of 10 ^-6 Pa to generate carbon at intervals. The activation step was completed when the current flowing during the activation step was saturated. As a result, an interval could be formed only in the region where the Pt-Pd film was deposited.

The device fabricated as described above was evacuated again to 665 × 10 ^-7 Pa or more in the same vacuum vessel, heated to 150 ° C. in the vicinity of the device, heated for 3 hours or more, and then returned to room temperature. . At that time, the degree of vacuum was 133 × 10 ⁻⁸ Pa. After that, the device was driven.

The driving voltage was Vf = 15 V, 0 V was applied to the first electrode 2, 15 V was applied to the second electrode 4, and a correction voltage Vc = −6 V was applied to the third electrode 5.

The anode voltage was Va = 10 kV, and the distance H between the electron-emitting device and the anode electrode was H = 2 mm. Here, the size of the electron beam was observed using an electrode coated with a phosphor as an anode electrode. The electron beam size referred to here is 10% of the peak luminance of the emitted phosphor.
Up to the size of the area.

As a comparative example, the effect of the present invention was confirmed by setting the correction voltage Vc to 0V.

As a result, in the comparative example, the main beam position was observed at a position shifted by 120 μm from immediately above the element. on the other hand,
In the present embodiment, the main beam position is observed almost immediately above the element by applying a correction voltage of −6 V to the beam.

In the comparative example, the beam diameter (X direction) was 20
What was 0 μm was 150 μm in Example 1. The beam diameter (Y direction) was 320 μm in the comparative example, and 280 μm in Example 1.

The electron emission efficiency Ie / If was 1.4% in the comparative example, but slightly decreased in the present example to 0.9%.
5%.

As described above, the efficiency slightly decreases, but as described above, since the original efficiency can be increased even in the vertical type, the efficiency can be sufficiently reduced.

(Example 2) As Example 2, an image forming apparatus shown in FIG. 8 was manufactured by using an electron source in which the electron-emitting devices of Example 1 were arranged in a matrix as shown in FIGS. Is shown.

After taking out the correction electrode Dcx of the X-direction wiring of the power supply to an external terminal, all the wirings were wired to the same potential of -6 V, and an image forming apparatus having a matrix wiring could be formed.

In this embodiment, since there is no displacement of the electron beam from the electron source, there is an effect that it is not necessary to displace the position of the electron source and the phosphor when assembling the image forming apparatus.

(Embodiment 3) Next, an embodiment of an electron-emitting device according to the present invention will be described with reference to FIG. FIG.
FIG. 1 shows a structural diagram of Embodiment 3 which is an embodiment of the electron-emitting device according to the present invention.

In this embodiment, the three-dimensional arrangement of the first electrode 2, the second electrode 4, and the third electrode 5 is different.

However, the arrangement from above the element is the same as that of the second electrode 4
The third embodiment is the same as the first embodiment except that a groove for separating the third electrode 5 is provided, and the thicknesses of the insulating layer 3 and the second electrode 4 are the same as the first embodiment.

In this embodiment, as in the first embodiment,
When the correction voltage Vc was −6 V, the same effects of the beam shape and the electron emission efficiency were obtained.

The specific effect of the present embodiment is to ensure the stability of the electron-emitting portion. That is, in the configuration of the first embodiment,
2nd electrode 4 and 3rd electrode 5 which do not emit an electron without an interval
During this period, a higher voltage is applied than between the first electrode 2 and the second electrode 4.

However, since there is no conductive film 6 in this region, the actual electric field intensity is lower than that of the emission portion.

However, if conductivity is added to this portion due to dust or the like during the etching of the second electrode 4, there is a possibility that an electric field may be applied to the portion or a leak current may occur. .

In this embodiment, the second electrode 4 and the third electrode 5
Since the gap is not exposed, such a possibility is eliminated. Therefore, a stable electron-emitting device can be obtained.

(Embodiment 4) Next, an embodiment of the electron-emitting device according to the present invention will be described with reference to FIG. FIG.
FIG. 2 shows a structural diagram of Embodiment 4 which is an embodiment of the electron-emitting device according to the present invention.

This embodiment differs from the third embodiment in the three-dimensional arrangement of the first electrode 2, the second electrode 4, and the third electrode 5.

However, the arrangement from above the element is almost the same as in the first embodiment, and the thicknesses of the insulating layer 3 and the second electrode 4 are also the same as in the first embodiment.

In this embodiment, the third electrode 5 is uniformly stacked on the substrate, and the first electrode 2 and the insulating layer 3 are stacked on the third electrode 5 with the insulating layer 121 interposed therebetween. .

As described above, the condition for driving the correction voltage Vc and the condition for obtaining the required effect are substantially determined if the element shape (particularly the value of the width W1) is determined. Therefore, even when a plurality of elements are arranged and individual control is required, there is little need for the correction electrode to have an individual structure for each element.

Therefore, in this embodiment, patterning of the third electrode 5 can be eliminated. Further, in the case of an image forming apparatus, it is possible to eliminate the pattern for taking out the correction electrode.

(Embodiment 5) Next, an embodiment of the electron source according to the present invention will be described with reference to FIG. In FIG.
FIG. 13 shows a circuit diagram of Embodiment 5 which is an embodiment of the electron source according to the present invention.

In this embodiment, the correction electrode D in the X direction
Since the terminal c is common to the two elements, the number of wirings by the correction electrode can be reduced to half. In the electron source of the present embodiment, unlike the conventional surface conduction type device in which the electron beam is displaced from the device, the electron beam reaches just above the device.

Therefore, in this embodiment, it is possible to freely change the asymmetric arrangement as shown in FIG. 13 without devising the Y-direction wiring.

(Embodiment 6) Next, an embodiment of an electron-emitting device according to the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 14 shows a structural diagram of an embodiment 6 in which the electron-emitting devices according to the present invention are arranged in a matrix, FIG. 15 shows a wiring diagram of the electron-emitting device shown in FIG. 14, and FIG. FIG. 1 is a perspective sectional view of an image forming apparatus using the electron-emitting device shown in FIG.
FIG. 7 shows a block diagram of a drive circuit of the image forming apparatus shown in FIG.

In FIG. 14, the portion where the electron-emitting device is formed is almost the same as in the first embodiment. In FIG. 14,
The second electrode 4 is formed on the element portion and its outer periphery.
The outer peripheral part is present at a certain distance from the element part,
Another insulating layer 141 is interposed between the electrode 2 and the third electrode 5.

In the present embodiment, it is necessary to reduce the thickness of the second electrode 4 in order to obtain a highly efficient electron source. In the case of wiring, a large parasitic resistance may be generated, but the effect can be reduced.

Further, by increasing the thickness of the insulating layer 3 at the intersection of the first electrode 2 and the third electrode 5 with the wiring of the second electrode 4, the capacitance between the wirings can be reduced.

However, if the outer peripheral portion is too close to the second electrode 4, the convergence effect of the electron orbit by the first electrode 3 and the third electrode 5 itself becomes small, and the tendency becomes similar to the case where W1 is increased. Therefore, caution is required.

It is desirable that the distance between the two is not less than ten times the characteristic distance Xs determined under the above-mentioned driving conditions.

Further, in this embodiment, the third electrode 5
The resistor 142 is connected. In the present embodiment, the first electrode 2 and the third electrode 5 are both connected to the X-direction wiring, but the end of the third electrode 5 is
A voltage lower than that of the first electrode 2 is applied. This allows
The same potential arrangement as in the first embodiment can be obtained, and the same effect can be obtained.

Further, in this embodiment, as shown in FIGS. 15, 16 and 17, it is possible to perform a simple matrix drive normally used in a conventional electron source by arranging the electron sources. .

Here, in the electron-emitting device, the electron source and the image forming apparatus according to the present invention, as shown in FIG. 3, for example, the first electrode 2 as the first electrode layer of the present invention The conductive film 6a as the first conductive portion of the present invention is separated.

The second electrode layer of the present invention
The electrode 4 and the conductive film 6b as the second conductive portion of the present invention are separated. Then, the conductive film 6a and the conductive film 6
A gap 7 is formed between the gap 7 and the gap b.

However, the electron-emitting device, the electron source, and the image forming apparatus according to the present invention are not limited to the above-mentioned shapes, and various modifications can be made.

For example, a conductive film 6 as shown in FIG.
The first electrode 2 and the second electrode 4 may extend to, for example, the side wall of the insulating layer 3 and have a gap without using the conductive film 6a and the conductive film 6b. In this case, the first electrode 2
Electrons are emitted from at least one of the first and second electrodes 4. Even in this case, the same effects as those of the above-described embodiments and examples can be obtained.

The electrode from which electrons are emitted is not limited to the conductive film 6a.
It may also be possible to emit from the conductive film 6b, the first electrode 2, the second electrode 4, and the like.

[0282]

As described above, according to the present invention, the second electrode which is not in contact with the first electrode layer whose width is equal to or less than a predetermined width is provided.
Is disposed on the insulating layer facing the anode electrode, and further, the third electrode layer as a correction electrode is provided, so that the electron emission efficiency is within a practical range, It is possible to provide an electron-emitting device, an electron source, and an image forming apparatus capable of improving electron convergence and forming a high-definition image.

[Brief description of the drawings]

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

FIG. 2 is a process chart of an example of a method for manufacturing the electron-emitting device shown in FIG.

FIG. 3 is a conceptual diagram for explaining a potential distribution and an electron beam trajectory in one embodiment of the electron-emitting device according to the present invention.

FIG. 4 is a partial structural view of one embodiment of an electron-emitting device according to the present invention.

FIG. 5 is a graph for explaining the operation of an embodiment of the electron-emitting device according to the present invention.

6 is a wiring diagram of an electron source obtained by arranging a plurality of the electron-emitting devices shown in FIG.

FIG. 7 is a circuit diagram of an electron source obtained by arranging a plurality of the electron-emitting devices shown in FIG.

FIG. 8 is a perspective sectional view of an embodiment of the image forming apparatus according to the present invention.

9 is a structural diagram of an example of a fluorescent film used in the image forming apparatus shown in FIG.

FIG. 10 is a block diagram illustrating an example of a driving circuit for driving the image forming apparatus illustrated in FIG. 8;

FIG. 11 is a structural diagram of Example 3 which is an example of the electron-emitting device according to the present invention.

FIG. 12 is a structural diagram of Example 4 which is an example of the electron-emitting device according to the present invention.

FIG. 13 is a fifth embodiment which is an embodiment of the electron source according to the present invention.
FIG.

FIG. 14 is a structural diagram of Embodiment 6 which is an embodiment in which the electron-emitting devices according to the present invention are arranged in a matrix.

15 is a wiring diagram of the electron-emitting device shown in FIG.

16 is a perspective sectional view of an image forming apparatus using the electron-emitting device shown in FIG.

17 is a block diagram of a driving circuit of the image forming apparatus shown in FIG.

FIG. 18 is a structural view of a conventional surface conduction electron-emitting device.

FIG. 19 is a conceptual diagram showing a potential distribution and electron arrival positions of a conventional surface conduction electron-emitting device.

FIG. 20 is a structural view of a conventional electron-emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 1st electrode 3 Insulating layer 4 2nd electrode 5 3rd electrode 6, 6a, 6b Conductive film 7 Interval 8 Anode electrode 9, 10, 11 Power supply 21 Conductive film 22, 23 Resist pattern 61 X direction wiring 62 Correction electrode wiring 63 Y direction wiring 81 Substrate 85 Phosphor 86 Black conductive material 91 Rear plate 92 Support frame 93 Glass substrate 94 Fluorescent film 95 Metal back 96 Face plate 97 High voltage terminal 98 Envelope 141 Insulating layer 142 Resistor 311 Substrate 312 , 313 electrode 314 conductive film 315 interval 316 anode electrode 317 correction electrode 1301 display panel 1302 switch 1303 control circuit 1304 shift register 1305 line memory 1306 synchronization signal separation circuit 1307 modulation signal generator

Claims (13)

[Claims] A first electrode layer formed on the substrate; an insulating layer formed on the substrate; a first electrode layer formed on the insulating layer; A second electrode layer that is not in contact with the electrode layer; and a second electrode layer that is formed on the substrate and that is applied with a voltage lower than a voltage applied to the first electrode layer. A third electrode layer in contact with the first electrode layer provided on the first electrode layer and capable of emitting electrons;
And a second conductive portion provided on the second electrode layer with a gap from the first conductive portion and capable of emitting electrons. 2. An insulating substrate, a first electrode layer formed on the substrate and capable of emitting electrons, an insulating layer formed on the substrate, and formed on the insulating layer A second electrode layer capable of emitting electrons, formed with a gap with the first electrode layer; and a voltage formed on the substrate and applied to the first electrode layer. An electron-emitting device, comprising: the first electrode layer and a non-contact third electrode layer to which a lower voltage is applied. 3. The electron-emitting device according to claim 1, wherein the gap is formed on a side wall of the insulating layer. 4. The method according to claim 1, wherein the third electrode layer is arranged on the substrate at a position facing the first electrode layer via the insulating layer. The electron-emitting device according to claim 1. 5. An anode electrode disposed at a distance H [m] from the substrate, wherein a drive voltage Vf [V] is applied between the first electrode layer and the second electrode layer. When an anode voltage Va [V] is applied to the anode electrode, a width W1 of the second electrode layer in a direction from the first electrode layer to the third electrode layer is defined by using π as a circular constant. The characteristic distance Xs is smaller than 10 times the characteristic distance Xs represented by the following equation (1).
Item 14. The electron-emitting device according to Item 1. Xs = (H · Vf) / (π · Va) (1) 6. A first electrode layer formed on an insulating substrate, an insulating layer formed on the substrate, and formed on the insulating layer and not in contact with the first electrode layer. A second electrode layer in contact with the first electrode layer, the third electrode being formed on the substrate and being applied with a voltage lower than the voltage applied to the first electrode layer; An electrode layer provided on the first electrode layer and capable of emitting electrons.
An electron emission portion comprising: a second conductive portion capable of emitting electrons provided on the second electrode layer with a gap from the first conductive portion; An electron source, wherein a plurality of electron sources are formed on a substrate. 7. A first electrode layer capable of emitting electrons formed on an insulating substrate, an insulating layer formed on the substrate, and a first electrode layer formed on the insulating layer. A second electrode layer formed to have a gap with the first electrode layer and capable of emitting electrons, and a voltage lower than a voltage formed on the substrate and applied to the first electrode layer. An electron source, comprising: a plurality of electron-emitting portions each including the first electrode layer and a non-contacting third electrode layer, to which an electron-emitting portion is applied. 8. The electron source according to claim 6, wherein the gap is formed on a side wall of the insulating layer. 9. The method according to claim 6, wherein the third electrode layer is arranged on the substrate at a position facing the first electrode layer via the insulating layer. The electron source according to claim 1. 10. An anode electrode disposed at a distance H [m] from the substrate, wherein a drive voltage Vf [V] is applied between the first electrode layer and the second electrode layer. When the anode voltage Va [V] is applied to the anode electrode, the width W1 of the second electrode layer in the direction from the first electrode layer to the third electrode layer is π 10. The method according to claim 6, wherein the peripheral ratio is smaller than 10 times the characteristic distance Xs represented by the following equation (2).
An electron source according to the item. Xs = (H · Vf) / (π · Va) (2) 11. The electron emitting portions are arranged in a matrix on the substrate, the first electrode layers of the individual electron emitting portions are connected to row wirings, and the second ones of the individual electron emitting portions are connected to each other. Are connected to column wirings orthogonal to the row wirings, and the third electrode layers of the individual electron-emitting portions are connected to the first wirings.
The electron source according to any one of claims 6 to 10, wherein the electron source is connected to a row wiring different from the row wiring to which the electrode layers are connected. 12. The electron emitting portions are arranged in a matrix on the substrate, the first electrode layers of the individual electron emitting portions are connected to row wiring, and the second ones of the individual electron emitting portions are connected to each other. Are connected to column wirings orthogonal to the row wirings, and the third electrode layers of the individual electron-emitting portions are connected to the first wirings.
The electron source according to any one of claims 6 to 11, wherein the electron source is connected via a resistor to the same row wiring as the row wiring to which the electrode layers are connected. 13. An electron source according to claim 6, further comprising an anode electrode arranged at a distance of H [m] from the insulating substrate, and near the anode electrode. An image forming member on which an image is formed by colliding with an electron beam of the generated electrons is disposed, and the image on the image forming member is substantially directly above the electron emission portion. An image forming apparatus, wherein a potential of a voltage applied to the third electrode layer of the electron source according to claim 1 is adjusted.