JP2001312958A - Electron source and image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron source of high precision and an image-forming device, capable of realizing both improvement of the electron emission efficiency and convergence of the electron orbit, at the same time. SOLUTION: The electron source is constituted with a plural number of the electron emission elements 13 being laid in parallel in the columnar direction, the neighbors in the row direction being laid shifted in its location by a half pitch with the mutual adjacent ones and each of the electron emission elements be arranged and shifted by a half pitch to the row direction by every other column, that is, it is the so-called a delta arrangement system. This contributes both to the improvement of the electron emission efficiency and converging the electron orbit and also realizes that the electron source can maintain a high precision and high efficiency of the electron emission characteristics over a long time. The image forming device combining the electron source of this delta arrangement system with the image forming mechanism can furnish stable and satisfactory images over a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron source using an electron-emitting device and an image forming apparatus such as an image display.

[0002]

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

As an example of the FE type, WPDyke & WWDo
lan, " Field Emission ", Advance in Electron
Physics, 8, 89 (1966) or CASpindt, " PHYS
ICALProperties of thin-film field emission cathode
s with molybdenium cones " J. Appl, Phys, .47,5248
(1976) are known.

[0004] An example of the MIM type is CAMead. " Oper.
ation of Tunnel-Emission Devices ", J.Apply.Phy
s., 32, 646 (1961).

In a recent example, Toshiaki. Kusunoki,
" Fluctuation-free electron emission from non-f
ormed metal-insulator-metal (MIM) cathodes Fabricate
d bylow current Anodic oxidation ", Jpn.J.Appl.P
hys, vol.32 (1993) pp.L1695, Mutsumi suzuki etal "
An MIM-Cathode Array for Cahtode luminescent Displ
ays ",IDW'96, (1996) pp. 529 and the like have been studied.

As an example of the surface conduction type, a report by Elinson (M.I. Elinson Radio Eng. Electron Phys., 10 (1965))
The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. is there.

Among the surface conduction type devices, those using the SnO ₂ thin film described in the above-mentioned Ellison report, those using the Au thin film (G. Dittmer. Thin Solid Films. 9, 317 (1972)),
n ₂ O ₃ / SnO ₂ by thin film (M.Hartwell and CGF
onstad, IEEE Trans. ED Conf., 519 (1983)).

Conventionally, especially in an image forming apparatus such as an image display apparatus, a flat panel display apparatus using liquid crystal has recently
Although it has become widespread in place of T, it has problems such as having to have a backlight because it is not a self-luminous type.
A self-luminous display device has been desired.

The self-luminous display device is an image display device in which an electron source in which a number of surface conduction electron-emitting devices are arranged and a phosphor that emits visible light by electrons emitted from the electron source are combined. And an image forming apparatus (for example, US Pat. No. 5,066,883).

As an example in which a large number of surface conduction electron-emitting devices are arranged and arranged, 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). An electron source in which a number of rows (wires) connected to each other are arranged in a row (ladder-like arrangement) (for example, JP-A-64-31332, JP-A-1-283737).
And Japanese Patent Application Laid-Open No. 1-257552.

[0011]

In a flat panel display device using the above-mentioned conventional surface conduction electron-emitting device,
It is known that the beam diameter of the electron beam on the anode is substantially determined by the magnitudes of Va and Vf and the distance H between the element and the anode (SID 98 Digest, Okuda, et. Al). Even the electron source given in the conventional example has a diameter of about sub-millimeter, and has a sufficient resolution as an image forming apparatus.

However, in recent years, higher resolution has been required for image forming apparatuses.

Accordingly, the problem to be solved by the present invention is to obtain a higher-definition electron beam (electron trajectory) by controlling the trajectory of electrons. It is to realize the improvement of.

As a conventional example for obtaining a high-definition beam diameter, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Application Laid-Open No. 14-214, an electrode for converging electrons is disposed above the emission part in addition to the electron emission electrode and the anode electrode, and a method for converging the electron orbit is disclosed in
As disclosed in JP-A-63461, a structure in which a converging electrode is arranged on the same plane as an electron-emitting portion has been proposed. However, the complexity of the manufacturing method, an increase in the element area, and the electron-emitting efficiency described later have been proposed. Was a problem.

As for the surface conduction type device, Japanese Patent Application Laid-Open No. 3-20941 proposes a reduction in the size of an electron-emitting device, and Japanese Patent Application Laid-Open No. 9-82214 proposes a higher efficiency. However, it is not enough to realize a high-definition image forming apparatus. Japanese Patent Application Laid-Open No. Hei 7-235256 discloses a similar structure to the present invention, which aims at a simple arrangement of electron-emitting devices and has no convergence function.

On the other hand, as a technique for displaying an image forming apparatus with high definition, a so-called delta arrangement is used in which the arrangement of elements in the row direction of the image forming member is formed every other row by shifting by half a pitch in the column direction. May be configured. Although this configuration is effective as a configuration that can achieve high definition even with a small number of pixels, there is a problem in that the arrangement of the electron sources is complicated or the area of the unit pixel is large.

In the surface conduction type device, a conventional delta arrangement of image forming members is constructed by using a relatively simple structure by utilizing the positional shift of the electron trajectory.
There are 3146 and JP-A-9-237598. In this configuration, as a usable electron-emitting device,
A planar electron-emitting device as shown in FIG. 20 and a vertical electron-emitting device as shown in FIG. 21 are disclosed.

However, in order to achieve high definition, there is another aspect in that the amount of electron emission per pixel is reduced by reducing the pixel area per pixel, and as a high-definition electron emission element, It is necessary to achieve high efficiency at the same time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a high-definition electron source and a high-definition electron source capable of simultaneously improving the electron emission efficiency and converging the electron orbit. An object of the present invention is to provide an image forming apparatus.

[0020]

According to the present invention, there is provided an electron source comprising a plurality of electron-emitting devices arranged on a substrate in parallel in a row direction and adjacent in a column direction. An electron source in which the electron sources are arranged so as to be shifted from each other by half, wherein the electron-emitting device has a high-potential electrode layer laminated on a low-potential electrode layer via an insulating layer, and a layer of the insulating layer and the high-potential electrode layer. A side wall having a thickness is formed, the side wall is covered with a conductive film, and a gap is formed in a portion of the conductive film which covers a layer thickness region of the insulating layer.

It is preferable that the side wall is an opening edge formed by removing the insulating layer and the high-potential electrode layer which are once laminated on the whole.

In the electron-emitting device, a driving voltage applied between the high-potential electrode and the low-potential electrode is Vf;
When an anode electrode is arranged at a distance H above the electron-emitting device and an anode voltage Va is applied to the anode electrode, when a width in a vertical direction from the side wall of the high-potential electrode is w1, w1 Is the characteristic distance Xs = (H × Vf)
It is preferable that the width be larger than 15 times the characteristic distance Xs defined by / (π × Va).

[0023] On the side of the electron-emitting device on which the insulating layer and the high-potential electrode layer are laminated, an interlayer insulating layer for insulating the adjacent electron-emitting devices from each other is provided. It is preferable to be laminated over.

When the length of the region from the gap to the high potential electrode in the layer thickness direction is T1 and the length of the region from the gap to the low potential electrode in the thickness direction is T3, the high potential electrode is And if the drive voltage applied between the low potential electrodes is Vf and the work function of the high potential electrode is φwk, then T1 <A × exp [B × (Vf−φwk) / (Vf)] A = −0.50 + 0.56 × log (T3), B = 8.
It is preferable to satisfy the condition (7).

In the electron-emitting device, a driving voltage applied between the high-potential electrode and the low-potential electrode is Vf;
When an anode electrode is arranged at a distance H above the electron-emitting device and an anode voltage Va is applied to the anode electrode, when the width in the vertical direction from the side wall of the low-potential electrode is w2, w2 Is the characteristic distance Xs = (H × Vf)
It is preferable that the width be larger than 15 times the characteristic distance Xs defined by / (π × Va).

In the image forming apparatus according to the present invention, the above-mentioned electron source, an image forming member on which an image is formed by electrons emitted from the electron emitting element arranged in the electron source, and the electron emitting device And driving means for driving and controlling electrons emitted from the element according to the information signal.

In the image forming member, it is preferable that one pixel is arranged corresponding to one of the electron-emitting devices arranged in the electron source.

It is preferable that the image forming members are arranged in a delta arrangement.

Preferably, the image forming member is a three primary color phosphor.

It is preferable that the fluorescent film forming one pixel of the image forming member has an elliptical shape.

It is preferable that the image forming members have the same pitch in the x direction and the y direction.

Preferably, the image forming members have different pitches in the x and y directions.

Preferably, the image forming member has a stripe structure.

Therefore, according to the electron source of the present invention, it is possible to realize an electron source capable of maintaining high definition and highly efficient electron emission characteristics for a long time.

According to the image forming apparatus of the present invention, a stable and good image can be formed for a long time.

[0036]

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.

A preferred embodiment of the present invention will be described. 1 and 2 are views showing an example of an electron source according to the present invention.

FIG. 1 is a plan view, and FIG. 2 is a wiring diagram. 1 and 2, reference numeral 11 denotes a lower wiring, 12 denotes an upper wiring, 13 denotes an electron-emitting device, 14 denotes an image forming member, 15 denotes a row wiring, and 16 denotes a column wiring.

In the electron source according to the present invention, as shown in FIGS. 1 and 2, a plurality of electron-emitting devices are arranged in parallel in the row direction and half-adjacent in the column direction. In other words, the feature is that a so-called delta arrangement is adopted, in which the arrangement of the electron sources is arranged at half pitch in the column direction every other row.

It is a special report that an image forming apparatus is constituted by combining a so-called dot matrix arrangement corresponding to the electron source on a one-to-one basis and one of image forming members in a stripe arrangement arranged in a stripe pattern. .

In the electron source according to the present invention, the electron arrival position is not right above the electron emission portion, but arrives at a position shift. Therefore, the image forming member is also displaced according to the electron arrival position.

FIG. 3 is a diagram for explaining the configuration of one unit of electron-emitting device in the electron source of the present invention, and FIG. 4 is a diagram showing an example of a method for manufacturing the electron source.

In FIG. 3, 1 is a substrate, 2 is a first electrode,
3 is an insulating layer, 4 is a second electrode, 5 is a conductive film, 6 is a gap,
21 is an interlayer insulating layer, and 31 is a column direction wiring of an adjacent element.

The electron emission device applicable to the present invention is a surface conduction type electron emission device in which electrons are emitted from the gap 6 by a voltage applied between the first electrode 2 and the second electrode 4 which are a pair of electrodes. In particular, an insulating layer 3 is laminated on the first electrode 2 between the electrodes 2 and 4, and a gap 6 exists in a portion of the conductive film 5 covering the side wall of the insulating layer 3, that is, a so-called vertical type electron. It has a discharge section.

Further, the first electrode 2 is connected to a low potential electrode, and the second electrode 4 is connected to a high potential electrode. Further, the low-potential electrode is connected to the lower wiring, the high-potential electrode is connected to the upper wiring, and the low-potential electrode is exposed by the opening in which the high-potential electrode and a part of the insulating layer are removed, so that the electron-emitting portion is exposed. It is characterized in that a side wall having a low potential region and a high potential region are formed.

Hereinafter, description will be given along the manufacturing method of FIG.

The surface is sufficiently cleaned beforehand, for example, laminated with SiO ₂ by sputtering or the like on quartz glass, glass with reduced impurities such as Na, blue plate glass, blue plate glass, Si substrate, etc. Laminate, alumina, etc.
The first electrode 2 is formed on the ceramic insulating substrate 1 (FIG. 4A).

The first electrode 2 is laminated by a general vacuum film forming technique such as a vapor deposition method and a sputtering method. As a material of the first electrode 2, a general conductor material is used, for example, Ni, C
metals or alloys such as r, Au, Mo, W, Pt, Ti, Al, Cu, Pd, and Pd, Au, RuO ₂ , Pd
Metal or metal oxide and printed conductor composed of glass or the like, such as -ag, is appropriately selected from semiconductor materials such as transparent conductor and polysilicon or the like In ₂ O ₃ -SnO _2.

The thickness of the first electrode 2 is set in a range from several nm to several mm. The first electrode 2 is a lower wiring 1 shown in FIG.
1, which also serves as the row direction wiring 15.

Further, an interlayer insulating layer 21 is partially formed (FIG. 4B).

The interlayer insulating layer 21 is mainly arranged on the adjacent bus line. In some cases, it is arranged so as to be connected to the high potential electrode of the element.

The interlayer insulating layer 21 is formed by a general vacuum film forming method such as an evaporation method or a sputtering method, a thermal oxidation method, an anodic oxidation method, or the like. The material of the interlayer insulating layer 21 is preferably SiO ₂
In addition, 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 interlayer insulating layer 21 is set in the range of several tens nm to several tens μm, but is not necessarily required because it is configured to reduce the capacity of the electron source in the matrix wiring.

Further, the insulating layer 3 and the second
The electrodes 4 are stacked (FIG. 4C).

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 film thickness of the insulating layer 3 is set in a range from several nm to several tens μm, and preferably from several tens nm to several μm.

The second electrode 4 is laminated by a general vacuum film forming technique such as a vapor deposition technique and a sputtering method. As described above, the second electrode 4 may be made of the same material as the first electrode 2 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, preferably about several tens nm, for improving the electron emission efficiency. When the film thickness is small, a heat-resistant material is particularly desirable. Second electrode 4
Is an upper wiring 12 shown in FIG.

Next, the insulating layer 3 and the second electrode 4
Is formed (FIG. 4D).

In this step, mask patterning is performed by photolithography, and an etching method is selected according to the material of each of the electrodes 4 and the insulating layer 3.

Next, a step of forming a gap 6 between the first electrode 2 and the second electrode 4 to form an electron emitting portion is performed. For this purpose, a conductive film 5 is further formed (FIG. 4E).

The material of the conductive film 5 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
Oxidation such as O ₃ , borides such as HfB ₂ , ZrB ₂ , LaB ₆ ,
Carbides such as TiC, ZrC, SiC, WC, TiN, Z
It is appropriately selected from nitrides such as rN and HfN, semiconductors such as Si and Ge, organic polymer materials, carbon and carbon compounds such as amorphous carbon, graphite, and diamond-like carbon.

The thickness of the conductive film 5 is set in the range of several Å to several hundreds of nm, and is designed together with the resistance value and the step coverage.

Further, a voltage is applied between the first and second electrodes 2 and 4, and a step called an energization forming step is performed to form a gap 6 (FIG. 4 (f)).

In the energization forming, the voltage waveform is preferably a pulse waveform. The energization forming may be performed in a vacuum atmosphere as in the subsequent activation step. The end of the energization forming process is terminated when a voltage is applied to the extent that the conductive film 5 is not broken in the pulse gap, the current is measured, the resistance is detected, and the resistance value becomes 1 MΩ or more. You.

The forming step is not limited to the energization forming and includes a process of forming a local high resistance state on the conductive film 5.

Further, there is a case where the electron-emitting device manufactured as described above is placed in a vacuum vessel, and after evacuating to a vacuum atmosphere, an activation and stabilization step is 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 the vacuum vessel from an organic gas supply source, and the voltage waveform is applied to the first electrode 2 and the second electrode 4 in an atmosphere containing an organic substance gas. The waveform voltage is applied repeatedly. This includes
There are a method of continuously applying a pulse with a pulse peak value being a constant voltage, and a method of applying a voltage pulse while increasing the pulse peak value.

The preferred organic materials for producing carbon
The partial pressure depends on the form of carbon, the shape of the vacuum
Since it differs depending on the type or the like, it is set as appropriate according to the case.
Suitable organic substances include alkanes, alkene aliphatics
Hydrocarbons, aromatic hydrocarbons, alcohols, alde
Hides, ketones, amines, phenols, carvone,
Organic acids such as sulfonic acid, specifically, methane,
C such as tan and propane _nH_{2n + 2}Saturated hydrocarbon represented by
C, such as ethylene, ethylene, and propylene_nH_2nTable with composition formula such as
Unsaturated hydrocarbons, benzene, toluene, methanol
, Ethanol, formaldehyde, acetoaldehyde
, Acetone, methyl ethyl ketone, methylamine, d
Tylamine, phenol, formic acid, acetic acid, propionic acid, etc.
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 at most 10 × 10 ⁻⁵ Pa, particularly preferably at most 1 × 10 ⁻⁶ Pa. When the inside of the vacuum vessel is evacuated, a vacuum evacuation 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 inside of the vacuum vessel is evacuated, 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 electron-emitting device are easily evacuated. The heating temperature at this time is 8
The temperature is preferably 5 hours or more at 0 ° C. to 200 ° C., 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.

The operation of the electron-emitting device applicable to the present invention will be described with reference to FIGS.

In FIGS. 5 and 6, the same members as those in FIGS. 1 to 4 are denoted by the same reference numerals. In FIG. 5, reference numeral 8 denotes a power supply for applying a voltage to the first electrode 2 and the second electrode 4, and reference numeral 9 denotes a power supply for applying a voltage to the anode electrode 7.

In the present invention, the first electrode 2 and the second electrode 4
A low potential is applied to the first electrode 2 and a high potential is applied to the second electrode 4, that is, the driving voltage Vf
And the element current If flows. Further, an anode voltage Va is given by a power supply 9 for applying a voltage to the anode electrode 7. The electron-emitting device applicable to the present invention is a surface-conduction type electron-emitting device. The electrons emitted from the gap 6 are scattered on the high potential electrode (second electrode 4) and then arranged at a distance H. The emission current Ie flows by being captured by the anode electrode 7 which has been discharged.

In the electron-emitting device applicable to the present invention, the driving voltage Vf is set to several volts to several tens volts. The drive voltage Vf largely depends on the gap width D of the gap 6, and the larger the gap width D, the larger the drive voltage Vf.

In the electron source and the image forming apparatus using the electron-emitting device according to the present invention, the anode voltage V
a and the distance H between the electron-emitting device and the anode electrode 7 are appropriately designed. In the case of an electron source or an image forming apparatus, the smaller the distance H and the larger the anode voltage Va, the smaller the beam diameter, which is advantageous. However, on the other hand,
Discharge and difficulty in manufacturing the device are problematic. Therefore, a practical anode voltage Va exists in accordance with the distance H.

In the present invention, the distance H between the electron-emitting devices is
It is several tens μm to several tens mm, preferably several hundred μm to several mm. Also, the anode voltage Va corresponding thereto
Is several tens of volts to several tens of kV, preferably several hundred volts to several tens of kV.

Note that, with the gap 6 interposed, the conductive film 5
It is connected to the electrode 2 and the second electrode 4.

Further, the first electrode 2 is connected to a low potential to form a low potential region, and the second electrode 4 is connected to a high potential to form a high potential region.

Here, the efficiency and beam size of the conventional flat type electron-emitting device will be described first, and then the device applicable to the present invention will be described.

FIG. 20 is a diagram of a conventional surface conduction electron-emitting device. 20, reference numeral 2001 denotes a substrate;
2, 2003 are electrodes, 2004 is a conductive film, 2005 is a gap, and 2006 is an anode electrode.

In addition, there is a conventional vertical surface conduction electron-emitting device shown in FIG. In FIG. 21, 210
1 is a substrate, 2102 and 2103 are electrodes, 2104 is a step forming material, 2105 is a conductive film, and 2106 is a gap.

In the conventional planar surface conduction electron-emitting device, according to SID'98 Digest, Okuda. Et al, there is a gap on the order of nm between opposing electrodes, and when a driving voltage Vf is applied to this device, It is known that electrons are emitted (or injected through the substrate) from the tip of the low potential electrode to the opposite high potential electrode, and the electrons are isotropically scattered again at the tip of the high potential electrode (exactly Assuming that electrons are emitted isotropically from the tip of the high-potential electrode, it is known that the experiment and the numerical calculation prediction are consistent with each other.)

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

The characteristic distance Xs is expressed as follows: Xs = D / 2√ (1+ (2H ・ Vf / πVa ・ D) 2) ≒ (H ・ Vf) / (π ・ Va) (1) The distance between the emitting element and the anode electrode,
π is the pi, D is the gap width formed in the electron-emitting portion, Vf
Is a drive voltage, and Va is a voltage of the anode electrode 7.

The second approximation of the above equation (1) is 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. 20, the characteristic distance Xs is, as shown in FIG. 20, the distance from the gap 2005 to the point where the surface at the same potential as the high-potential electrode intersects the high-potential electrode on the equipotential surface appearing in vacuum. Is represented as

The electron emission efficiency is governed by a decrease in the number of electrons due to the fact that electrons emitted from the gap are partially absorbed by the high potential electrode due to multiple scattering until the electrons exceed the characteristic distance Xs. Although it is not clear about the ratio (scattering coefficient) β that is scattered by the collision of electrons of about several tens eV,
It is estimated that about one scattering is about 0.1 to 0.5. Since β is equal to or less than 1 in such a scattering mechanism, it is understood 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. 20, electrons emitted from the gap 2005 are emitted at least once on the high potential electrode facing within the characteristic distance Xs, and many electrons are emitted plural times. Due to scattering, the number of electrons that are taken into the high potential electrode and disappear is increased, and the electron emission efficiency is reduced.

Further, the efficiency of the conventional planar type surface conduction electron-emitting device depends on the arrival distribution of scattered electrons and the characteristic distance Xs
Alternatively, it is known that Xsｓ = γ × Xs (γ is a coefficient = 0.67). The distribution of the scattered electrons is related to the maximum flight distance of the electrons, and the gap width D
(Defined as T2 in the present invention) and the driving voltage Vf
And the work function Wf (defined as the work function φwk in the high-potential region in the present invention).

In the vertical element applicable to the present invention shown in FIG. 6, the maximum flight distance of electrons is related to the efficiency.
However, since the space potential distribution formed by the drive voltage between the anode electrode and the element is different, the structure is different from the case of the planar type and becomes complicated.

However, it is known that there are conditions under which the efficiency is higher than that of the planar type due to the three-dimensional configuration.
One of them is to arrange the position of the high potential electrode above the low potential electrode. It has also been found that it is important to further provide the position of the gap on the side wall portion and to minimize the distance of the side wall from the gap to the high potential electrode.

Further, if the height T1 from the gap to the end of the high-potential electrode is equal to or less than the characteristic distance Xs with reference to the characteristic distance Xs defined in the conventional planar element, the characteristic distance Xs
The efficiency is determined mainly by the distance of T1 without depending on s. Then, it was also found that when T1 was less than the maximum flight distance until the first scattering, electrons without scattering existed.

Based on the above considerations, a detailed study of the behavior of electrons in the vertical type, particularly the behavior of scattering, showed that as a function of the work function φwk and the drive voltage Vf of the material used in the high potential region, It has been clarified that there is a region where the efficiency can be improved due to the function of the distance between T1 and T3, that is, the effect of the shape near the electron-emitting portion.

In the electron-emitting device applicable to the present invention, the work function φwk in the high-potential region depends on the material of the scattering surface material, and may be the conductive film 5 or the second electrode 4. Or a deposited material deposited by activation. Work function φw introduced into the formula
k may be an average value of the work function of the entire scattering surface, and generally, 3 to 5 eV can be applied.

FIG. 7A is an example of a graph showing T1 and the electron emission efficiency, and FIG. 7B is a graph for explaining a change in efficiency. In FIG. 7, the horizontal axis is T1
(Nm) and is logarithmic. The vertical axis shows the efficiency η
And the efficiency of reaching the anode, and is expressed linearly.

In FIG. 7A, the efficiency sharply decreases as T1 increases, but the curve is divided into two stages. This is correlated with the number of scattering of the arriving electrons. FIG. 7B shows the efficiency of reaching the anode depending on the number of scatterings. The first-stage curve in FIG. 7A is a region where electrons without scattering mainly reach, and the second-stage curve is a region where electrons without scattering and mainly electrons with multiple scattering reach. It is considered that The intersection of the first-stage and second-stage curves is indicated by T1max, and this point is considered to be an inflection point at which the main scattering frequency changes.

FIG. 8A shows Vf, φwk and T1ma.
The relationship with x was shown in a graph. The horizontal axis is a linear display, and the vertical axis is a logarithmic display. When the driving conditions are determined, it can be seen that an effect can be expected to improve the efficiency, that is, a shape in which electrons without scattering can reach the anode electrode can be determined.

FIG. 8B shows the explanation of (Vf-φwk) / Vf represented by the horizontal axis.

Assuming that the driving condition is Vf, an electric field is formed near the electron emitting portion so as to equally divide the space. (Vf
The equipotential surface (−φwk) is at the position shown by the thick line in FIG. 8B, and it can be said that this surface is a wall where the emitted electrons can no longer reach the low potential side.

The change in T1 changes the position of the equipotential surface, changes the direction and strength of the electric field, and changes the electron trajectory. This electric field exerts a great effect on the electrons because of Xs or 200 of the gap width T2.
It is estimated to be about twice.

In the present invention, the gap width T2 is several nm.
By setting T1 from several tens of nm to several hundreds of nm, it becomes a region that greatly affects the flight of scattered electrons, and the effect of the shape can be expected.

The graph of FIG. 8A shows the dependence of T3. It can be seen that, like T1, the shape of T3 is also a factor that changes the electric field around the gap. Where T
The smaller the value of 1 is, the more effective the efficiency is. The larger the value of T3 is, the better the efficiency is. The difference is that T3 = ∞ becomes almost constant.

From the graph of FIG. 8A, regarding T1max, T1max = A × exp (B × (Vf−φwk) / (Vf)) (2) A = −0.50 + 0.56 × log (T3) B = 8.7 The above equation is derived. Here, T1 and T3 are distances (unit is mm), φwk is a work function value (unit is eV) in a high potential region, Vf is a drive voltage (unit is V), A is a function of T3, and B is a constant. is there.

As described above, T1 is important as a parameter related to scattering for the electron emission efficiency.
It was found that when T1 was set in the range of the expression (2), an effect of remarkably improving efficiency was obtained.

Therefore, the element applicable to the present invention is:
Even in the vertical type, T1 to T3 are applied so as to particularly aim at high efficiency. In such a configuration, the number of electron scattering times is reduced.

Under these conditions, the efficiency is improved and
A change in the shape of the electron beam can also be expected. The electron beam shape will be described.

First, the shape and beam size of an electron beam of a conventional surface conduction electron-emitting device will be described.

FIG. 20 shows the arrival position of electrons in the conventional electron-emitting device. The electron beam largely shifts from the emission position when it reaches the characteristic distance Xs at the top of the element, and shifts significantly due to the distorted electric field at the top.

The electron beam diameter is almost equal to the amount of shift from immediately above the electron emitting portion to the main arrival position of the electron beam. Therefore, the electron beam diameter is SID'98 Digest,
It is known from Okuda, et al that it can be described as Lh {4KhH} (Vf / Va) + L1 ... (3a) Lw {2KwH} (Vf / Va) ... (3b). Here, Lh is the vertical direction (y direction) of the electron beam, L1 is the element length in the y direction, L
w indicates the size of the electron 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. Va = 10 kV, H = 3 mm
Has a size of Lh to 0.5 mm and Lw to 0.25 mm.

In the electron-emitting device applicable to the present invention, a configuration in which T1 is smaller than the characteristic distance Xs is proposed. Therefore, when viewed from the anode electrode side,
The distance is small enough, similar to a conventional planar device,
Generally, the equations (3a) and (3b) can be almost applied. However, there is a difference between the coefficients of Kh and Kw, and especially, the value of Kw, which is the coefficient of the electron beam diameter in the x direction, becomes extremely small.
High definition is realized.

FIG. 5 shows an electron-emitting device applicable to the present invention. In the figure, the electron beam diameter in the x direction is Lx, and the electron beam diameter in the y direction is Ly.

FIG. 9 is an explanatory view showing the number of times of scattering of the device according to the present invention and the maximum position where electrons reach.

Electrons are bent in the x direction due to the effect of the space potential formed on the high-potential electrode. However, when scattering occurs on the high-potential electrode, the direction of the electron beam changes. , Its spread spreads inside the fan.
However, the intensity distribution is not uniform, and as the number of times of scattering is smaller, the intensity tends to be closer to the fan-shaped outer edge portion, and especially to the vicinity of the origin in the y direction.

On the other hand, an electron without scattering has a specific trajectory because its trajectory only bends due to the space potential determined by the drive voltage and the anode voltage while maintaining the directionality at the time of electron emission. Reach linearly.

Therefore, the arrival position of the electron beam due to the lower-order scattering and the arrival position of the electron beam due to the higher-order scattering are as shown in FIG.

In the configuration of the electron-emitting device applicable to the present invention, the average number of scattering of the electrons reaching the anode electrode can be reduced by reducing the distance of T1, whereby the electron beam can be reduced. It is possible to concentrate the intensity distribution on the fan-shaped outer edge. As a result, as shown in FIG. 5, the relative electron beam intensity distribution can be remarkably changed in the x direction, the y direction, and further in the x direction.

Since the electron beam shape is usually defined in a region where the intensity ratio to the peak intensity is sufficiently attenuated, the electron beam shape can be reduced by changing the intensity distribution.

Further, by selecting a shape in which the main component of electrons reaching the anode electrode is a component without scattering as defined by the formula (2) according to the present invention, the electron beam can reach only linearly. And Kw and Kh can be reduced.

As described above, it is understood that high efficiency and high definition can both be achieved by reducing the number of scatterings and using electrons without scattering as a main component in the present invention.

Next, another condition for forming the above-described high-definition electron beam will be described.

FIG. 10 shows the dependence of the width w2 of the low potential electrode from the gap 6 (side wall) in the vertical direction when w1 in FIG. 5 is fixed.

As a result of examining the width of the two as a condition for achieving the above-mentioned expression (2) and achieving high efficiency, it was found that the width must be sufficiently larger than the characteristic distance Xs.
Further, as a result of a detailed study, it was found that, as shown in FIG. 10, the standard distance is 15 times the characteristic distance Xs.

Also, this 15-fold guideline can be applied to the distance of w1, and by taking a constant distance, the aforementioned (2)
It is suggested that conditions satisfying the equations (3) to (3) are satisfied.

Therefore, in the electron-emitting device applicable to the present invention, it is preferable that w1 and w2 be larger than 15 times the characteristic distance Xs.

The above-mentioned condition is a case where the height is constant, and a different condition is obtained when the height is different. However, if w1 is larger than 15 times the characteristic distance Xs,
Since the influence of the potential on the outside is reduced, the height can be changed. In the present invention, it is necessary for the matrix drive to increase the thickness of the interlayer insulating layer to reduce the capacitance. This makes it easier to think about the effect of the potential on the thickness.

As described above, using the electron-emitting device applicable to the present invention, the conditions such as w1, w2, w3, T1, and T3 are considered in accordance with the driving condition of the device. The efficiency of the electron source and the electron beam diameter are designed, so that the arrangement of the electron source can be designed.

As a result, the electron source itself can be arranged in a delta arrangement, and furthermore, a high-definition electron source can be realized.

As an example of the arrangement, there is a case in which the y-direction wirings are arranged evenly and in parallel. Further, there is a configuration in which the y-direction wiring in which the area of the y-direction wiring is changed between the pixel region and the bus line portion is provided.

In any method, an electron source having a delta arrangement can be formed, and a high-definition and high-efficiency image forming apparatus can be constituted by a driving circuit for driving the electron source having a delta arrangement.

The beam shape of the electron-emitting device applicable to the present invention is such that the beam diameter in the x direction becomes smaller than that in the y direction. Can also be planned. Therefore, the shape of the image forming member may be elliptical.

In addition, it is possible to arrange the electron sources so that the pitches of the electron sources are different in the x direction and the y direction according to the beam shape of the electron source. Further, the image forming member may have a stripe configuration.

Next, an electron source according to the present invention and an image forming apparatus using the same will be described with reference to FIGS.

FIG. 11 is a diagram of an image forming apparatus in which the electron-emitting devices shown in FIG. 3 are arranged in the mxn matrix shown in FIG. 1 and formed using the formed electron source.

In the image forming apparatus of the present invention, electron emission elements arranged in a so-called delta arrangement are arranged in a simple matrix. That is, a plurality of electrodes arranged in a matrix in the x direction and the y direction, one of the electrodes of a plurality of electron-emitting devices arranged in the same row are 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.

In the x-direction, m row-direction (X-direction) wirings (Dox1, Dox2,..., Doxm) 72 are arranged, and in the y-direction, n column-direction (Y-direction) wirings (Doy).
1, Doy2, Doy3,..., Doyn) 73.

The first electrode 2 constituting the electron-emitting device also serves as the lower wiring 11 and is electrically connected to the row wiring 72. The second electrode 4 also serves as the upper wiring 12, and is electrically connected to the column wiring 73.

Wiring other than the simple matrix wiring configuration described above can also be employed. For example, connection is made at both ends of a plurality of electron-emitting devices arranged in parallel, a large number of rows of electron-emitting devices are arranged (row direction), and a direction perpendicular to the wiring (column direction).
There is also a ladder-like wiring in which electrons from the electron-emitting device are controlled and driven by a control electrode (grid electrode) disposed above the electron-emitting device.

The x-direction wiring and the Y-direction wiring are formed by vacuum evaporation,
It can be made of a conductive metal or the like formed by using a printing method, a sputtering method, or the like. The material and thickness of the wiring are appropriately designed. The widths, Px1, Py1, and Py2, are designed according to the guidelines shown in the present invention (see FIG. 3).

The electrons emitted from the electron-emitting device in the present invention 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 equal to or 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, by appropriately applying a pulse-like voltage 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, individual elements can be selected and driven independently using simple matrix wiring.

Further, in FIG. 11, reference numeral 71 denotes an electron-emitting device; 81, an electron source substrate on which a plurality of electron-emitting devices are arranged;
Reference numeral 1 denotes a rear plate to which an electron source substrate 81 is fixed, and 96 denotes a face plate in which a fluorescent film 94 and a metal back 95 are formed on the inner surface of a glass substrate 93. Reference numeral 92 denotes a support frame, and 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. May be an integral member.

The phosphor 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.

The heating means for firing and sealing can employ various means such as lamp heating using an infrared lamp or the like and a hot plate, but is not limited to these.

Further, the adhesive 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 embodiment of the present invention, and is not limited to this, and various types 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 setting a support (not shown) called a spacer between the face plate 96 and the rear plate 91, the envelope 98 having sufficient strength against atmospheric pressure can be configured.

FIG. 12 is a schematic diagram showing the fluorescent film 94 formed on the face plate 96. The fluorescent film 94 can be composed of only the phosphor 85 in the case of monochrome. In the case of a color fluorescent film, a black conductive material 86 called a black stripe, a black matrix, or the like is used.
And the phosphor 85.

The purpose of providing the black stripes and the black matrix is to make the mixed colors, etc., stand out by making the painted portions between the phosphors 85 of the necessary three primary color (R, G, B) phosphors black in color display. The purpose is to prevent the reduction in contrast due to reflection of external light on the fluorescent film 94. As a material of black stripe,
In addition to a commonly used material containing graphite as a main component, a material having conductivity and low light transmission and reflection can be used.

The shape of the fluorescent film 85 is a circle as shown in FIG. Further, the shape may be another shape corresponding to the shape of the electron beam, for example, an elliptical shape as shown in FIG.

In the electron-emitting device applicable to the present invention, x
Since the beam diameter is small in the direction, the structure shown in FIG.
An elliptical shape as shown by is suitable.

Such an elliptical electron beam is convenient even if the pitch of the phosphor is different between the x direction and the y direction, and the pitch in the x direction can be made smaller than that in the y direction.

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. Usually, a metal back 95 is provided on the inner surface side of the fluorescent film 94. The purpose of providing the metal back 95 is to improve the brightness by mirror-reflecting the light emitted from the phosphor toward the inner surface side to the face plate 96 side, and to function as an electrode for applying an electron beam acceleration voltage. And protecting the phosphor 94 from damage caused by the collision of negative ions generated in the envelope 98. The metal back 95 can be manufactured by performing a smoothing process (usually called “filming”) on the inner surface of the fluorescent film after the fluorescent film is manufactured, and then depositing Al using vacuum evaporation or the like.

The face plate 96 is essentially provided with the 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.

In the present invention, since the electron beam reaches directly above the electron-emitting device 71, the electron beam is positioned and positioned so that the fluorescent film 94 is disposed immediately above the electron-emitting device 71.

Next, the envelope (panel) subjected to the sealing step
A vacuum sealing step for sealing 98 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 and 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. To maintain the pressure after the envelope 98 is sealed, a getter process may be performed. This is the envelope 98
Immediately before or after the sealing is performed, the getter disposed at a predetermined position (not shown) in the envelope 98 is heated by heating using resistance heating, high-frequency heating, or the like to form a deposition film. Processing. The getter is usually made of Ba or the like as a main component, and maintains the atmosphere in the envelope 98 by the adsorption action of the deposited film.

The image forming apparatus constructed by using the electron sources of the delta arrangement manufactured by the above-described processes has Dox1 to Dox1.
When a voltage is applied via Doxm and Doy1 to Doyn, 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 and emit light to form an image.

FIG. 13 is a block diagram showing an example of a drive circuit for performing display in accordance with an NTSC television signal.

The scanning circuit will be described with reference to FIG. The scanning circuit 1302 includes m switching elements inside (in the drawing, S1 to Sm are schematically shown).
is there.

Each switching element has a DC voltage source Vx2
Output voltage or 0 V (ground level), and is electrically connected to terminals Dox1 to Doxm 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 for example, FE
It can be configured by combining switching elements such as T.

In the case of the present embodiment, the DC voltage source Vx2 uses a driving voltage applied to an unscanned element based on the characteristics (electron emission threshold voltage) of the electron emission element of the present invention. It is set to output a constant voltage that is equal to or lower than the 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
Synchronization debt TSY sent from synchronization signal separation circuit 1306
TSCAN and TSFT for each part based on NC
And TMRY control signals.

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 can be configured using a general frequency separating (filter) circuit or the like. . The synchronization signal separated by the synchronization signal separation circuit 1306 is composed of a vertical synchronization signal and a horizontal synchronization signal.
This is shown as a SYNC signal. The luminance signal component of the image separated from the television signal is represented as a DATA signal for convenience.
The DATA signal is input to the shift register 1304.

The shift register 1304 converts a serially input DATA signal into serial / parallel data for each line of an image.
3 operates based on the control signal TSFT sent from the shift register 1304.
Shift clock). The data of one line of the image subjected to the serial / parallel conversion (corresponding to the drive data of the N elements of the electron emission elements) is output from the shift register 1304 as N parallel signals Id1 to Idn.

A line memory 1305 is a storage device for storing data of one line of an image for a required time only.
The contents of Id1 to Idn are stored as appropriate according to the control signal TMRY sent from the control circuit 1303. The stored contents are output as Id′1 to Id′n and input to the modulation signal generator 1307.

Modulated signal generator 1307 outputs image data I
A signal source for appropriately driving and modulating each of the electron-emitting devices applied to the present invention according to each of d′ 1 to Id′n, and an output signal of the signal source is provided on the display panel 1301 through terminals Doy1 to Doyn. It is applied to the electron-emitting device applied to the invention.

As described above, the electron-emitting device applied to the present invention has the following basic characteristics with respect to the emission current Ie. That is, a clear threshold voltage Vth is required for electron emission.
And electron emission occurs only when a voltage higher than Vth is applied. For a voltage equal to or higher than the electron emission threshold, the emission current also changes according to the change in the voltage applied to the device.

From this, when a pulse-like voltage is applied to the device, for example, when a voltage lower than the electron emission threshold is applied, no electron emission occurs, but a voltage higher than the electron emission threshold is applied. In this case, an electron beam is output. At this time, the intensity of the output electron beam can be controlled by changing the pulse peak value Vm. Also,
By changing the pulse width Pw, it is possible to control the total amount of charges of the output electron beam.

Therefore, a voltage modulation method, a pulse width modulation method, or the like can be adopted as a method of modulating the electron-emitting device in accordance with an input signal. 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, the output signal DATA of the synchronization signal separation circuit 1306 needs to be converted into a digital signal.
An A / D converter may be provided at the output unit 6. In this connection, 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, the modulation signal generator 13
For 07, for example, a D / A conversion circuit is used, and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation system, the modulation signal generator 1307 includes, for example, a counter for counting the number of waves output from the high-speed oscillator and the oscillator, and a comparison for comparing the output value of the counter with the output value of the memory. The circuit which combined the device (comparator) is used. If necessary, an amplifier for voltage-amplifying the pulse-width-modulated signal output from the comparator to the drive voltage of the electron-emitting device applied to 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 can be used as the modulation signal generator 1307, and a level shift circuit and 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 adopted, and an amplifier for amplifying the voltage up to the driving voltage of the electron-emitting device applied to the present invention is added as necessary. You 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. Although the NTSC system is used as the input signal, the input signal is not limited to the NTSC system, but may be a PAL or SECAM system or a TV signal including a larger number of scanning lines (for example, the MUSE system or the like). High-definition TV). Further, in addition to the image display device, the present invention can be used as an image forming device or the like as an optical printer including a photosensitive drum or the like.

[0179]

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

(First Embodiment) FIG. 1 is a diagram showing an electron source manufactured according to the first embodiment, and FIG. 3 is a diagram showing details of an electron-emitting device constituting the electron source. The first embodiment has a 250 μm square electron source in a delta array of square pixels,
This is an example of an image forming apparatus using the same.

Hereinafter, the manufacturing process of the electron-emitting device of this embodiment will be described in detail.

(Step 1) A blue plate was used as the substrate 1, and after sufficient cleaning, the first electrode 2 having a thickness of 1 was formed by sputtering.
Pum Al is deposited in a pattern of Py1 = 200 μm.
The first electrode 2 also serves as the row wiring 15.

(Step 2) Thereafter, ₂ μm of SiO ₂ is laminated as the interlayer insulating layer 21 and is formed into a predetermined shape by a photolithography step and etching.

(Step 3) The insulating layer 3 having a thickness of 8
0 nm of SiO ₂ was deposited, and the second electrode 4 was formed to a thickness of 50 nm.
nm of Ta was deposited.

(Step 4) In a photolithography step, spin coating of a positive type photoresist (AZ1500 / manufactured by Clariant), exposure and development of a photomask pattern were performed, and the mask pattern was transferred. Thereafter, the patterned photoresist was used as a mask.

(Step 5) Further, the insulating layer 3 and the second electrode 4 were dry-etched using CF ₄ gas. The resist mask was then peeled off. Thus, the second electrode 4 is separated. This second electrode 4 also serves as the column direction wiring 16.

In the structure thus formed, h1 = 0.13
μm, h2 = 2.13 μm, and L2 = 200 μm.
Also, w1 = 40 μm, w2 = 40 μm, w3 = 40 μm
m, and the high-potential electrode width is 80 μm in total.

The separation between the wirings in the y direction is 5 μm.
Width. Therefore, Px1 = 120 μm, Px2 =
By setting it to 60 μm, Px = Py = 250 μm.

(Step 6) Next, a 5 nm-thick Pt-Pd
A conductive film 5 was deposited on the above structure at L1 = 50 μm.
The Pt-Pd conductive film 5 was masked by using a photolithography technique and was selectively deposited by an ion sputtering method.

An image forming apparatus shown in FIG. 10 was constructed by using the electron source substrate thus manufactured (no gap was formed).

(Step 7) The electron source substrate is used as a rear plate, and the substrate provided with a dot matrix image forming member provided with a fluorescent film in a circular shape as shown in FIG. An envelope (panel) was produced using a frame and frit glass for connection.
The height of the support frame was adjusted so that the distance H between the electron source substrate and the image forming member was H = 2 mm.

(Step 8) Next, the envelope (panel) is evacuated through an exhaust pipe (not shown) to the first electrode 2 via the row wiring, and via the column wiring. And the second electrode 4
10V to 15V pulse voltage (ON time: 1msec
c / OFF time: 9 msec unipolar) and the Pt
A current was applied to the -Pd conductive film 5, and the gap 6 was formed by the forming step. The forming was terminated when the resistance between the upper and lower electrodes became 10 MΩ.

(Step 9) Next, in the same manner as in step 8, the first step was performed in an atmosphere of BN (benzonitrile) and 2 × 10 ⁻⁵ Pa.
A pulse voltage of 12 V to 15 V (ON time: 1 msec / OFF time: 9 msec, both electrodes) was applied to the electrode 2 and the second electrode 4 to generate carbon in the gap. The activation step is
It ended when the current flowing during the activation process was saturated.
As a result, a deposited film mainly composed of carbon was deposited with a thickness of several nm near the gap on the Pt-Pd conductive film.

After driving, it was confirmed by an electron microscope that the gap 6 was formed substantially at the center of the side wall of the insulating layer. Therefore, in this element, T1 ≒ 95 nm, T3 ≒ 35
nm.

(Step 10) The envelope produced as described above was evacuated again to 5 × 10 ⁻⁵ Pa or more, kept at 150 ° C. in the vicinity of the element, and heated for 5 hours or more.
Return to room temperature. At that time, the degree of vacuum was 1 × 10 ⁻⁶ Pa.

When this device was driven at Vf = 15 V and Va = 10 kV, the efficiency Ie / If = 0.7% (one device)
The following device characteristics were obtained. Under these conditions, the beam diameter of one element was Lx = 150 μm and Ly = 250 μm.

This element is converted into a characteristic distance Xs = 0.95 μm ≒ 1 μm in terms of driving conditions. Therefore, T1 is sufficiently smaller than the feature distance Xs, and high efficiency is obtained. Further, when the work function of the high-potential electrode is set to the work function of carbon φwk = 5 eV and substituted into equation (2),
It falls within the preferable range of T1 (T1 <120 nm). In this embodiment, w1 = 40 μm and w2 = 40 μm, and both are set to exceed 15 times the characteristic distance Xs.

Therefore, using this element, the pitch P
An image forming apparatus having a delta arrangement of square pixels of x = Py = 250 μm was realized with an electron source arrangement in which the y-direction wirings were arranged uniformly and in parallel.

In addition, good image display was achieved using the image forming apparatus and the driving circuit.

(Second Embodiment) Next, a case where T3 is changed as an electron-emitting device to which the present invention can be applied will be described in a second embodiment. A cross-sectional view is shown in FIG. Except for extending the dry etching time in (Step 5) of the first embodiment to increase T3 and excavating the first electrode 2 by 500 nm, other configuration sizes and operation methods are the same as those of the first embodiment. It is.

This device is similar to the first embodiment with T1Ｔ95 nm, but T3 is large, and T3 ≒ 540 nm. Therefore, the preferable range of T1 obtained by substituting into the equation (2) is T1max <340 nm, and T1
1 is smaller.

This device was made to have Vf = 15, as in the first embodiment.
V and Va = 10 kV, the efficiency Ie / If
= 1.2% (one device) was obtained. Under this condition, the beam diameter of one element is Lx = 130 μm
m, Ly = 250 μm, and the beam diameter in the x direction is the first
It was smaller than in the example. This is considered to result in a structure in which scattering was suppressed as a result of increasing T3, resulting in high efficiency and high definition.

As described above, with the configuration of the first and second embodiments, the image forming apparatus of the delta arrangement of the square pixels with the pitch Px = Py = 250 μm is realized by the electron source arrangement in which the y-direction wirings are arranged uniformly and in parallel. did it.

(Third Embodiment) FIG. 15 shows a third embodiment of the electron source of the present invention. In this embodiment, the electron-emitting portion and the low-potential electrode differ from the first embodiment by 90 degrees, and the high-potential region is parallel to the row wiring.

In the delta arrangement, a fine wiring width is required in the column direction to make the column direction uniform. On the other hand, in the electron-emitting device applicable to the present invention, w1, w2, and the like require a certain large area length, and it may be more advantageous to consider the arrangement in consideration of the direction.

In the third embodiment, the direction is changed by 90 degrees in consideration of w1 and w2. Thereby, w1 = 80 μ
m, w2 = 80 μm and w3 = 80 μm. In this embodiment, Py1 is set to 240 μm in order to make Py1 as wide as possible, and Px1 and Px2 are the same as in the first and second embodiments.

However, if L2 is not smaller than Px1, the wiring resistance of the column wiring increases, so that L2
2 = 60 μm and L1 = 30 μm.

Also in this embodiment, under the same driving conditions as those of the first embodiment, the electron beam from the element becomes opposite in the x and y directions and the emission length L1 becomes shorter in the first embodiment. Lx decreases, Lx = 220 μm, Ly = 1
It was 50 μm, and the efficiency was the same as in the first example.

That is, in the present configuration, Px
= Py = 250 μm.

(Fourth Embodiment) FIGS. 16 and 17 show a fourth embodiment. FIG. 16 is a plan view of an electron source, and FIG. 17 is a sectional view of an electron-emitting device of one pixel. The configuration around the gap is the same as in the first embodiment, and T1 and T3 are the same as in the first embodiment.

Up to now, the column-directional wiring has been arranged uniformly and on a straight line. However, in this embodiment, higher definition can be achieved by modifying the column-directional wiring. In the present embodiment, for example, Px = Py =
A 250 μm configuration is of course possible.

Further, a configuration for high definition will be described. That is, y
The direction is the same as in the first embodiment, and Px1
= 100 μm and Px2 = 20 μm. w1 = 40μ
m, w2 = 30 μm, and w3 = 30 μm.

In the present embodiment, the wiring electrode 41 is added to the column direction wiring in order to prevent the adjacent bus line from being locally thinned and increasing the parasitic resistance.

In this embodiment, the arrangement is such that Px = Py = 150 μm, and a high-definition electron source is possible.

When the electron-emitting device of this embodiment is driven, the device has the same efficiency and beam diameter as the first embodiment. However, in this embodiment, the beam diameter in the x direction is Lx = 150 μm
m, which falls within the pitch range, but in the y direction, Ly = 25.
0 μm, which is larger than the pitch. Therefore, FIG.
An elliptical fluorescent film as shown in (b) was used. That is, the pitch of the fluorescent film is 150 μm, the fluorescent film is an ellipse whose major axis is the y-axis, and the shape of the ellipse is 150 μm in the minor axis,
By setting the major axis to 250 μm, the beam diameter can be made substantially equal to the beam diameter of the element of the present invention.

With this configuration, Px = Py = 150
Good display was achieved with an image forming apparatus using a μm electron source.

(Fifth Embodiment) As a fifth embodiment, FIG. 18 shows an electron source configuration in the case where the pitches in the x direction and the y direction are different. FIG. 19 shows an arrangement of image forming members applied to the electron source.

Such a configuration is effective as a method for further increasing the definition of an electron source applicable to the present invention.

In the x direction, Px1 = 70 μm, Px2 =
It was 10 μm. w1 = 30 μm, w2 = 30 μm, w
3 = 10 μm. L1 = 50 μm, L2 = 2
00 μm.

In this configuration, Px = 100 μm, Py = 3
An arrangement of 00 μm is possible.

FIG. 19 shows an example of the fluorescent film 94 applicable to this embodiment. FIG. 19A shows an elliptical shape similar to FIG. As another configuration, a stripe structure shown in FIG. 19B is also possible. In this structure, the stripe width is
The fluorescent film may be 80 μm and the black stripe may be 20 μm.

With such a configuration, a fine delta arrangement can be formed in the column direction. In the image forming apparatus using the electron source of the present embodiment, good display was achieved.

[0223]

As described above, according to the present invention, by providing an electron source in a delta arrangement with a relatively simple configuration and manufacturing method, it is possible to simultaneously improve the electron emission efficiency and converge the electron orbit. In addition, it is possible to realize an electron source capable of maintaining high-definition and highly efficient electron emission characteristics for a long time.

When an image forming apparatus is formed by combining a delta array electron source with an image forming member, a stable and good image can be formed for a long time.

[Brief description of the drawings]

FIG. 1 is a plan view showing an electron source according to the present invention.

FIG. 2 is a wiring diagram showing an electron source according to the present invention.

FIG. 3 is a configuration diagram showing an electron-emitting device applicable to the electron source according to the present invention.

FIG. 4 is a process chart showing an example of a method for manufacturing an electron-emitting device applicable to the electron source according to the present invention.

FIG. 5 is a diagram for explaining an electron-emitting device applicable to the present invention.

FIG. 6 is a diagram for explaining an electron beam of an electron-emitting device applicable to the present invention.

FIG. 7 is a graph illustrating the efficiency of an electron-emitting device applicable to the present invention.

FIG. 8 is a graph and an explanatory diagram for explaining the efficiency of the electron-emitting device applicable to the present invention.

FIG. 9 is an explanatory diagram for explaining the reach of an electron beam of an electron-emitting device applicable to the present invention.

FIG. 10 is a graph for explaining the shape of an electron-emitting device applicable to the present invention.

FIG. 11 is an example of an image forming apparatus in which the electron sources of the present invention are wired in a simple matrix, and is a schematic perspective view with a part cut away.

FIG. 12 is a diagram illustrating a fluorescent film used in the image forming apparatus of the present invention.

FIG. 13 is a block diagram showing an example of a drive circuit for performing display in the image forming apparatus of the present invention in accordance with an NTSC television signal.

FIG. 14 is a sectional view showing a second embodiment of the electron-emitting device applicable to the present invention.

FIG. 15 is a plan view showing a third embodiment of the electron source according to the present invention.

FIG. 16 is a plan view showing a fourth embodiment of the electron source according to the present invention.

FIG. 17 is a view showing an electron-emitting device applicable to an electron source according to a fourth embodiment of the present invention.

FIG. 18 is a view showing an electron-emitting device applicable to an electron source according to a fifth embodiment of the present invention.

FIG. 19 is a diagram showing a fluorescent film used for an electron source according to a fifth embodiment of the present invention.

FIG. 20 is a schematic view showing a conventional planar electron-emitting device.

FIG. 21 is a schematic view showing a conventional vertical electron-emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 1st electrode 3 Insulating layer 4 2nd electrode 5 Conductive film 6 Gap 7 Anode electrode 8, 9 Power supply 11 Lower wiring 12 Upper wiring 13, 71 Electron emission element 14 Image forming member 15 Row direction wiring 16 Column direction wiring DESCRIPTION OF SYMBOLS 21 Interlayer insulating layer 31 Wiring of adjacent line 41 Wiring electrode 72 X direction wiring 73 Y direction wiring 81 Electron source 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

Claims (14)

[Claims] 1. An electron source in which a plurality of electron-emitting devices are arranged on a substrate in parallel in a row direction and adjacent to each other in a column direction with a half displacement. A high-potential electrode layer is stacked on the potential electrode layer via an insulating layer, a side wall is formed by the thickness of the insulating layer and the high-potential electrode layer, and the side wall is covered with a conductive film. An electron source, wherein a gap is formed in a portion covering the thickness region of the insulating layer. 2. The electron source according to claim 1, wherein the side wall is an opening edge formed by removing the insulating layer and the high-potential electrode layer which are once laminated on the whole. 3. A driving voltage applied between the high-potential electrode and the low-potential electrode is Vf, and an anode electrode is disposed above the electron-emitting device at a distance H from the electron-emitting device. When an anode voltage Va is applied to the anode electrode, when a width in a vertical direction from the side wall of the high-potential electrode is w1, w1 is defined by a characteristic distance Xs = (H × Vf) / (π × Va). The electron source according to claim 1, wherein the electron source is configured to have a width larger than 15 times the characteristic distance Xs. 4. An electron-emitting device comprising: an interlayer insulating layer that insulates between adjacent electron-emitting devices on a side on which the insulating layer and the high-potential electrode layer of the electron-emitting device are stacked; 4. The electron source according to claim 3, wherein the electron source is laminated on the insulating layer. 5. The high-potential electrode connected to the high-potential electrode from the gap in a thickness direction T1, and the high-potential region connected to the low-potential electrode from the gap in a thickness direction T3. The drive voltage applied between the potential electrode and the low potential electrode is Vf, and the work function of the high potential electrode is φwk
T1 <A × exp [B × (Vf−φwk) / (Vf)] A = −0.50 + 0.56 × log (T3), B = 8.
The electron source according to any one of claims 1 to 4, wherein the electron source satisfies the following condition: 6. The electron-emitting device, wherein a driving voltage applied between the high-potential electrode and the low-potential electrode is Vf, and an anode electrode is disposed above the electron-emitting device at a distance H, When an anode voltage Va is applied to the anode electrode, when a width in a vertical direction from the side wall of the low potential electrode is w2, w2 is defined by a characteristic distance Xs = (H × Vf) / (π × Va). The electron source according to claim 1, wherein the electron source is configured to have a width larger than 15 times the characteristic distance Xs. 7. An electron source according to claim 1, wherein: an image forming member on which an image is formed by electrons emitted from the electron-emitting device disposed in the electron source; A driving unit for driving and controlling electrons emitted from the electron-emitting device in accordance with the information signal. 8. The image forming apparatus according to claim 7, wherein one pixel of the image forming member is arranged corresponding to one of the electron-emitting devices arranged in the electron source. 9. An image forming apparatus according to claim 7, wherein said image forming members are arranged in a delta arrangement. 10. An image forming apparatus according to claim 7, wherein said image forming member is a phosphor of three primary colors. 11. A fluorescent film forming one pixel of the image forming member has an elliptical shape.
0. The image forming apparatus according to claim 1, 12. An image forming apparatus according to claim 11, wherein said image forming members have equal pitches in an x direction and a y direction. 13. An image forming apparatus according to claim 11, wherein said image forming members have different pitches in an x direction and a y direction. 14. An image forming apparatus according to claim 7, wherein said image forming member has a stripe structure.