JP2003092056A - Electron emitting element, electron source and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emitting element that has a large area of electron emission and can be driven by low resistance wiring, and of which electron beam diameter can be made small and manufacturing process is easy, and an electron source and an image forming device. SOLUTION: This is a hole type element that comprises a plurality of electron emitting parts that have nearly circular opening in one picture element, and in which the distance between the openings in a second direction that is perpendicular to a first direction is larger than the distance between the openings in the first direction. By forming the openings of the electron emitting parts in this way, low resistance wiring can be realized at the place where the distance of the openings are larger while making the emitting area large, and the overall drive can be made easy. And since the distance of the openings in the first direction is not larger than the diameter of the openings, emission area can be made large. Further, it is particularly effective when the diameter of the above openings is 5 μm or less.

Description

Detailed Description of the Invention

[0001]

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

[0002]

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

As an example of the FE type, W. P. Dyke &
W. W. Dolan, "Field Emissio
n ”, Advance in Electron Ph
ysics, 8, 89 (1956) or C.I. A. S
pindt, "PHYSICAL Properties"
ofthin-film field emissi
on cathodes with mollybden
ium cones ”, J. Appl. Phys., 4
7, 5248 (1976) and the like are known.

An example of the MIM type is C.I. A. Mead,
"Operation of Tunnel-Emis
sion Devices ", J. Apply. Phy
s. , 32, 646 (1961) and the like are known.

In a recent example, Toshiaki.
Kusunoki, "Fluctuation-fre
e electron emission from
non-formed metal-insulato
r-metal (MIM) cathodes Fabr
icated by low current Ano
dic oxidation ”, Jpn. J. App
l. Phys. vol. 32 (1993) pp. L16
95, Mutsumi Suzuki et al "An
MIM-Cathode Array for Ca
theode luminescent display
s ", IDW'96, (1996) pp. 529, etc. have been studied.

[0006]

In order to apply the electron-emitting device to the image forming apparatus, an emission current for causing the phosphor to emit light with sufficient brightness is required, and the driving voltage is small to reduce power consumption. In addition, in order to improve the definition of the display, it is required that the diameter of the electron beam with which the phosphor is irradiated is small, and it is important that the wiring can be designed so that it can be driven easily with low resistance. Is.

It is also an important item that manufacturing is easy. From such a viewpoint, a cold cathode electron source has been mainly developed for the image forming apparatus. However, there are still problems in the following points, and an image forming apparatus that can sufficiently satisfy the above requirements has not been created.

The MIM type is a lower electrode (cathode electrode layer)
In this structure, an insulating layer is arranged between the upper electrode and the upper electrode (gate electrode layer), and a voltage is applied between both electrodes to extract electrons. A small electron beam diameter can be realized because the direction of the internal electric field coincides with the direction of the emitted electrons and the potential distribution on the emission surface is not distorted, but electron scattering occurs at the insulating layer and the upper electrode. It is generally inefficient, which is not very preferable for low power consumption.

FIG. 12 shows a Spindt type electron-emitting device as an example of a conventional FE type. FIG. 12 shows a conventional Spi.
It is sectional drawing which showed an example of the ndt-type electron-emitting device typically.

In FIG. 12, 10 is an insulating substrate, and 40
Is a cathode electrode layer (low potential electrode), 30 is an insulating layer, 21
Is a gate electrode layer (high potential electrode), 50 is a microchip, and 60 is an equipotential surface.

When a bias is applied between the microchip 50 having a curvature r and the gate electrode layer 21, the microchip 50 is
Electrons are emitted from the tip toward the anode. The amount of emitted electrons is determined by the distance d between the gate electrode layer 21 and the tip of the microchip 50, the gate voltage Vg, and the work function of the material of the emitting portion.

That is, it is a factor that determines the performance of the device that the distance d between the gate electrode layer 21 and the microchip 50 is controlled and manufactured.

However, it is difficult to control the distance d with good reproducibility, and the amount of emission current varies from element to element.
Further, a metal piece or the like generated at the time of lift-off short-circuits the microchip 5 and the gate electrode layer 21, and when a voltage is applied between the microchip 50 and the gate electrode layer 21 during driving, heat is generated at the short-circuited portion, and the short-circuited portion is generated. And destruction of the surrounding area occurs.

This reduces the effective emission area. The variation due to each element as described above causes unevenness in brightness when applied as an image forming apparatus, for example, and is very annoying.

Further, in this example, since electrons are emitted from one emission point, if the emission current density is increased in order to cause the phosphor to emit light, thermal destruction of the electron emission portion is induced and the FE element is It will limit the lifespan.

Further, ions existing in a vacuum may sputter the tip of the microchip intensively to shorten the life of the device.

It should be noted that the electrons emitted into the vacuum travel perpendicularly to the equipotential surface, but in the structure shown in FIG. 12, the equipotential surface 60 is formed in the hole along the microchip 50. become.

Therefore, the electrons emitted from the tip of the microchip 50 tend to spread. A part of the emitted electrons is absorbed by the gate electrode layer 21, and the amount of electrons reaching the anode is reduced. The amount of electrons absorbed by the gate electrode layer 21 tends to increase as the distance d decreases.

In order to overcome such drawbacks of the FE element, various examples have been proposed as individual solutions.

As an example of preventing the spread of the electron beam, there is an example in which a focusing electrode is arranged above the electron emitting portion.

In this example, the emitted electron beam is focused by the negative potential of the converging electrode. However, in this example, a more complicated process than the above-described manufacturing process is required, resulting in an increase in manufacturing cost.

As an example of reducing the electron beam diameter without disposing the focusing electrode, there is a method of forming no microchip such as the Spindt type.

For example, JP-A-8-096703, JP-A-8-096704, and JP-A 8-264.
There is one described in Japanese Patent Publication No. 109.

This has the advantage that electrons are emitted from the thin film arranged in the hole, and therefore a flat equipotential surface is formed on the electron emission surface and the spread of the electron beam is reduced.

Further, by using a low work function constituent material as the electron emitting substance, electrons can be emitted without forming a microchip, and a low driving voltage can be achieved. There is also an advantage that the manufacturing method is relatively simple.

Further, since the electron emission is performed on the surface,
The electric field is not concentrated, the chip is not broken, and the life is long. In these, the plane layout of the electron emitting portion has a structure of holes formed at equal intervals as shown in FIG. 13A, or a linear electron emitting area as shown in FIG. 13B. However, the probability of electron emission is not high yet,
The issue is how to obtain a large number of electron-emitting portions to stably emit electrons and how to reduce the electron beam diameter. FIG. 13 is a plan view schematically showing the plane of a conventional electron-emitting device.

FIG. 14 shows an example in which the electron-emitting device is applied as an image forming apparatus. FIG. 14 is a diagram schematically showing a conventional image forming apparatus.

The lines of the gate electrode layer 21 and the lines of the cathode electrode layer 40 are arranged in a matrix, and the electron-emitting devices 14 are arranged at the intersections of both lines, which are at the intersections selected according to the information signal. Electrons are emitted from the electron emitting device 14, accelerated by the voltage of the anode 12, and enter the phosphor 13. This is a so-called tripolar device.

When the application to the image forming apparatus such as the display as described above is considered by the field emission type electron emitting device, (1) the electron emitting area is large. (2) Driving can be performed with low resistance wiring. (3) The electron beam diameter is small. (4) The manufacturing process is easy. However, it has been difficult for the conventional electron-emitting device to satisfy them at the same time.

The present invention has been made in order to solve the above-mentioned problems of the prior art. The object of the present invention is to provide a small electron beam diameter, a large electron emission area, and a high efficiency electron emission at a low voltage. An object of the present invention is to provide a field emission type electron-emitting device, an electron source, and an image forming apparatus which are capable of and easy to manufacture.

[0031]

In order to achieve the above object, in order to achieve the above object, the electron-emitting device of the present invention is formed on an insulating substrate or a first insulating layer. A first conductive layer; a second insulating layer laminated on the first conductive layer; a second conductive layer laminated on the second insulating layer; A substantially circular opening formed on the first conductive layer from the second insulating layer to the second conductive layer; and an electron emission material, and the first circular opening in the opening. An electron emission layer laminated on a conductive layer, and by applying a voltage between the first conductive layer and the second conductive layer, the electron emission layer in the circular opening is formed. An electron-emitting device that emits electrons from an electron-emitting layer, the device including a plurality of electron-emitting portions having the opening in one pixel, One than between the first direction of the opening distance is characterized by a larger distance between the opening of the first perpendicular second direction direction.

By thus forming the opening of the electron emitting portion, it is possible to realize a low resistance wiring in a place where the distance between the opening portions is large even though the emitting area is large, and it is possible to comprehensively drive the device. Further, the electrons emitted into the vacuum go toward the anode as they are, and the spread of the electron beam is small, so the electron beam diameter is small.

Also in terms of shape effect, each electron-emitting device is substantially circular, the potential distribution is uniform, and there is no singular point, and stable operation is possible.

The structure is very simple and the manufacturing process is easy.

Therefore, the field emission type electron-emitting device having the features of the present invention has a large electron emission area, low resistance wiring, a small electron beam diameter, and an easy manufacturing process. Can be applied to the image forming apparatus.

The electron-emitting device according to the present invention is the first
There is one or more inter-opening distances in the second direction, and one or more inter-opening distances in the second direction, and the largest inter-opening distance in the first direction is the second direction. Is not larger than the smallest distance between the openings of,
The degree of freedom in beam design and resistance design can be increased.

The electron-emitting device according to the present invention is the first
The distance between the openings in the direction of is not larger than the diameter of the openings, and a large emission area can be taken.
Further, it is particularly effective when the diameter of the opening is smaller than 5 μm.

Further, the electron-emitting device according to the present invention is preferably characterized in that the electron-emitting layer is separated between the openings, and by eliminating mutual interaction between the electron-emitting devices, It promotes electron emission.

The electron-emitting device according to the present invention is preferably characterized in that the electron-emitting layer contains carbon, and the electron-emitting layer contains amorphous carbon, diamond-like carbon or diamond.

The electron-emitting device according to the present invention is the first
A conductive layer, an insulating layer arranged on the first conductive layer and having a plurality of openings, and a plurality of openings arranged on the insulating layer and arranged in the first conductive layer. A second conductive layer having a plurality of openings communicating with each other, and an electron emission layer disposed on the first conductive layer positioned in each opening disposed in the insulating layer. An electron-emitting device that emits electrons from the electron-emitting layer in the opening when a voltage is applied between the first conductive layer and the second conductive layer. The distance between the plurality of openings in the second direction perpendicular to the first direction is larger than the distance between the plurality of openings in the direction.

Further, the electron source according to the present invention is characterized in that the electron-emitting devices are wired in a matrix, and preferably the first direction and the second direction are along the matrix wiring. And

Further, the image forming apparatus according to the present invention is characterized by including an electron source and an image forming member which forms an image by the electrons emitted from the electron source.

Further, the image forming apparatus according to the present invention is preferably characterized in that the image forming member is a phosphor which emits light by collision of electrons.

Therefore, the electron source and the image forming apparatus to which the field emission type electron-emitting device having the features of the present invention is applied can be improved in performance.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
Unless otherwise specified, the material, the shape, the relative arrangement, and the like are not intended to limit the scope of the present invention thereto.

The description of the embodiment of the electron-emitting device according to the present invention, which will be given below, also serves as the description of the embodiment of the electron source and the image forming apparatus according to the present invention.

FIG. 1 is a plan view showing an electron-emitting device having the most basic structure of the present invention, and FIG. 2 is a sectional view taken along the line AA ′. FIG. 1 is a plan view showing the structure of the electron-emitting device according to the present invention, and FIG. 2 is a sectional view showing the structure of the electron-emitting device according to the present invention.

In FIGS. 1 and 2, 1 is an insulating substrate,
Reference numeral 2 is a second electrode, 3 is an insulating layer, and 4 is a first electrode.
7 is an electron emission layer.

Here, although the first electrode 4 shows a conductive material different from that of the second electrode 2, there is no problem even if the same material is used. W is the diameter of the hole.

Vg is the voltage applied between the first electrode 4 and the second electrode 2 (including the electron emission layer 7), and Va is the second voltage.
The voltage applied between the electrode 2 and the anode 12 of the
Is the electron emission current. Eh is an electric field formed by Vg. 6 is an equipotential surface. D is the distance between the anode and the electron emission layer.

When Vg and Va are applied to drive the element, an electric field Eh is formed, and the shape of the equipotential surface 6 inside the hole is determined by Vg and W, the shape, the dielectric constant of the insulating layer and the like. Outside of the hole, although it depends on D, Va forms a substantially parallel equipotential surface.

According to the shape of the present invention, as shown in FIG. 1, the distance between the openings in the first direction (for example, the vertical direction in FIG. 1) is such that the circular electron emitting portions are closely packed, while the second Direction (for example, the lateral direction in FIG. 1) is sparse, and the potential distribution in the electron emission portion is uniform at any emission point while the electron emission density is increased, and the resistance of the wiring can be reduced.
A concrete and most prominent example will be described with reference to FIG. FIG. 3 is a plan view showing the structure of the electron-emitting device according to the present invention.

FIG. 3A shows an example in which the diameters of the electron emitting portions are a and the intervals are evenly arranged as a. In FIG. 3B, as in the present invention, the first direction (FIG. 3) is used. An example is shown in which the electron-emitting portions are densely arranged in contact with each other in the vertical direction) and are arranged at intervals of a in the second direction (horizontal direction in FIG. 3).

In FIG. 3 (a), the holes of the electron emitting portions are arranged alternately, but otherwise the electron emitting portions are connected to each other and the gate electrodes are separated, so that a voltage is applied to the gate. Since they are gone, I arranged them in a staggered manner.

Assuming that the number of rows in FIG. 3B is m and the number of electron emitting portions existing in one row is n, the total number is nm.
It becomes an individual.

On the other hand, in FIG. 3A, it is nm- (m-1), which is reduced by m-1.

In terms of resistance, the sheet resistance of the conductive layer is ρ
Then, in FIG. 3B, it is about mρ in the pixel, and since it does not generally become a large value, there is no problem in driving.

On the other hand, in FIG. 3A, when A becomes small, the variation in the process also becomes large, and there is a risk that the conductive layer is separated by the opening of the electron emitting portion or the resistance becomes large in an extremely narrow path. There is.

Further, unlike the case where the opening shape is a line shape, it has a symmetric shape in any electron emitting portion, and there is an advantage that the potential distribution is made uniform.

That is, while the electron emission area is equivalent to the line shape, an ideal potential distribution is formed,
It becomes possible to control the trajectory of the electron beam.

Further, the influence on other electron emission points in the vicinity of one electron emission point can be eliminated by this structure, and good electron emission can be realized. The electron-emitting device of the present invention is particularly effective when the diameter of the opening is 5 μm or less.

That is, when the pixel size becomes small and the electron beam needs to be made small, the diameter of the opening is 5 μm.
Although it is made smaller, the electron emission area is also reduced due to the small pixel size at the same time. Therefore, if the electron emission area is increased, the distance between the openings is also reduced and the resistance is increased. The effect of the present invention is not denied even when the opening and the distance between the openings are large, but the effect becomes remarkable when the size of the opening is 5 μm or less.

Further, the electron emission area on the device of the present invention is the entire surface of the electron emission layer 7. Since the electron emission area is wide, the electron emission layer 7 has good durability against ion bombardment existing in a vacuum.

Furthermore, the device of the present invention has a very simple structure in which lamination is repeated, the manufacturing process is easy, and the device can be manufactured with a high yield. (The manufacturing method will be described later).

Although an extreme example is shown here as shown in FIG. 3, it goes without saying that the same effect can be obtained even if the openings are not in contact with each other in the first direction.

The electron-emitting device according to the embodiment of the present invention described above will be described in more detail. A manufacturing method of an embodiment of the electron-emitting device according to the present invention will be described with reference to FIG. 4, but it goes without saying that the manufacturing method is not limited to this. FIG. 4 is a diagram showing a manufacturing method of an embodiment of the electron-emitting device according to the present invention.

First, the surface of the quartz glass was thoroughly washed in advance, quartz glass, glass in which the content of impurities such as Na was reduced,
Si on blue plate glass, silicon substrate, etc. by sputtering
Any one of a laminated body in which O ₂ is laminated and an insulating substrate made of ceramics such as alumina is used as the insulating substrate 1, and the first electrode 4 is laminated on the insulating substrate 1.

The first electrode 4 is generally conductive and is formed by a general vacuum film forming technique such as a vapor deposition method and a sputtering method. The material of the first electrode 4 is, for example, Be, M
g, Ti, Zr, Hf, V, Nb, Ta, Mo, W, A
1, metal such as Cu, Ni, Cr, Au, Pt, Pd, or alloy material, TiC, ZrC, HfC, TaC, Si
Carbides such as C and WC, HfB ₂ , ZrB ₂ , LaB ₆ , C
borides such as eB ₆ , YB ₄ , GdB ₄ , TiN, ZrN,
It is appropriately selected from nitrides such as HfN, semiconductors such as Si and Ge, organic polymer materials, amorphous carbon, graphite, diamond-like carbon, carbon in which diamond is dispersed, and carbon compounds. There is no particular limitation.

The thickness of the first electrode 4 is set in the range of several tens nm to several mm, preferably in the range of several hundred nm to several μm. Alternatively, a conductive emitting material may be used as the first electrode.

Then, as shown in FIG. 4B, an electron emission layer 7 is deposited on the first electrode 4 subsequent to the first electrode 4.

The electron emission layer 7 is formed by vapor deposition, sputtering, CV.
It is formed by a general vacuum film forming technique such as D method or a photolithography technique. The material of the electron emission layer 7 is, for example,
It is appropriately selected from amorphous carbon, graphite, diamond-like carbon, carbon in which diamond is dispersed, and carbon compounds.

Carbon materials having a low work function are preferable, and among them, diamond thin film, diamond-like carbon, amorphous carbon and the like are preferable.

The film thickness of the electron emission layer 7 is set in the range of several nm to several hundreds nm, and preferably in the range of several nm to several tens nm. After laminating with the first electrode, photolithography and etching steps may be collectively performed (FIG. 4B).

Further, without depositing the electron emission layer 7 here,
In some cases, the electron emission layer is deposited on the first electrode after forming the holes.

Then, the insulating layer 3 is deposited. Insulation layer 3
Is formed by a general vacuum film forming method such as a sputtering method, a CVD method, a vacuum vapor deposition method, or the like, and its thickness is set within a range of several nm to several μm, preferably several tens nm to several hundreds. selected from the nm range. Si is the preferred material
A material having a high breakdown voltage that can withstand a high electric field, such as O ₂ , SiN, Al ₂ O ₃ , CaF, and undoped diamond is desirable.

Further, the second electrode 2 is deposited subsequent to the insulating layer 3. The second electrode 2 has conductivity like the first electrode 4, and is formed by a general vacuum film forming technique such as a vapor deposition method and a sputtering method. The material of the second electrode 2 is, for example, Be, Mg, Ti, Zr, Hf, V, Nb, Ta,
Mo, W, Al, Cu, Ni, Cr, Au, Pt, Pd
Metal or alloy material such as TiC, ZrC, HfC, T
Carbides such as aC, SiC, WC, HfB ₂ , ZrB ₂ , L
boride such as aB ₆ , CeB ₆ , YB ₄ , GdB ₄ , TiN,
It is appropriately selected from nitrides such as ZrN and HfN, semiconductors such as Si and Ge, and organic polymer materials. The thickness of the second electrode 2 is set in the range of several nm to several μm, and is preferably selected in the range of several nm to several hundred nm.

The first electrode 4 and the second electrode 2 may be made of the same material or different materials, and may be formed by the same method or different methods (FIG. 4 (c)).

Next, as shown in FIG. 4D, the hole pattern 8 is formed by the photolithography technique.

Then, as shown in FIG. 4E, the insulating layer 3 is selectively removed by, for example, wet etching to complete a device. In the example in which the insulating layer 3 is made of SiO ₂ , buffered hydrofluoric acid or the like is used. It is appropriately selected depending on the material.

In the etching process, a smooth and vertical etching surface is desirable, and an etching method may be selected according to the material of each layer 4, 2, 3 and 7.

As described above, finally, the electron emitting layer 7 may be selectively deposited on the first electrode 4. It goes without saying that there is no particular limitation. Although the resistance layer between the electron emission layer and the first electrode is not mentioned here, it may be formed of amorphous silicon or the like if necessary, and there is no particular limitation.

The width of the first electrode (including the electron emission layer 7) is appropriately set according to the material and resistance of the device, the work function and drive voltage of the electron emission material, and the required shape of the electron emission beam. It

It is usually selected from the range of several hundred nm to several hundred μm. Similarly, the width of the second electrode is appropriately set depending on the material and resistance of the device and the arrangement of the electron-emitting devices.
Usually, it is selected from the range of several hundred nm to several hundred μm. The diameter W of the hole is appropriately set according to the material and resistance of the element, the work function and drive voltage of the material of the electron-emitting device, and the required shape of the electron-emitting beam.

Usually, W is selected from the range of several hundred nm to several tens of μm. The present invention has a great effect in reducing the beam diameter, and the smaller the W, the greater the effect. Therefore, it is preferably several μm or less.

The thicknesses of the insulating layer 3 and the electron emission layer 7 greatly affect the potential distribution. This is also a design matter, and it is preferable that it is optimally designed with W et al.

Each is usually selected from the range of several hundreds nm to several tens of μm, but preferably several μm or less.

Application examples of the electron-emitting device to which the present invention is applied will be described below. By arranging a plurality of electron-emitting devices of the present invention on a substrate, for example, an electron source or an image forming apparatus can be constructed.

Various arrangements of electron-emitting devices are adopted. As an example, a plurality of electron-emitting devices are arranged in a matrix in the X and Y directions, one of the electrodes of the plurality of electron-emitting devices arranged in the same row is commonly connected to a wiring in the X direction, and the same column is used. There is a simple matrix arrangement in which the other of the electrodes of the plurality of electron-emitting devices arranged in the above is commonly connected to the wiring in the Y direction.

The simple matrix arrangement will be described in detail below. An electron source obtained by arranging a plurality of electron-emitting devices to which the present invention can be applied will be described below with reference to FIG. FIG. 5 is a schematic configuration diagram showing an electron source having a simple matrix arrangement according to the present invention.

In FIG. 5, 61 is an electron source substrate, 62 is an X-direction wiring, and 63 is a Y-direction wiring. 64 is an electron-emitting device of the present invention.

The m X-direction wirings 62 are Dx1 and Dx.
2, ... Dxm, and can be composed of a conductive metal or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The wiring material, film thickness, and width are appropriately designed.

The Y-direction wiring 63 has Dy1, Dy2, ... D.
It is composed of n wirings of yn and is formed similarly to the X-direction wiring 62. An interlayer insulating layer (not shown) is provided between the m X-direction wirings 62 and the n Y-direction wirings 63 to electrically isolate the two (m and n are both Positive integer).

The interlayer insulating layer (not shown) is made of SiO ₂ or the like formed by a vacuum vapor deposition method, a printing method, a sputtering method or the like. For example, it is formed in a desired shape on the entire surface or a part of the electron source substrate 61 on which the X-direction wiring 62 is formed.
The film thickness, material, and manufacturing method are appropriately set so as to withstand the potential difference at the intersection of the X-direction wiring 62 and the Y-direction wiring 63. X
The directional wiring 62 and the Y-directional wiring 63 are drawn out as external terminals.

A pair of electrodes (not shown) forming the electron-emitting device 64 are electrically connected to the m X-direction wirings 62, the n Y-direction wirings 63, and a wire made of a conductive metal or the like. .

The material forming the X-direction wiring 62 and the Y-direction wiring 63, the material forming the connection, and the material forming the pair of element electrodes may be the same or may be the same as some of the constituent elements. May be different.

These materials are appropriately selected, for example, from the materials of the element electrodes (second electrode 2, first electrode 4) described above. When the material forming the element electrode and the wiring material are the same, the wiring connected to the element electrode can also be referred to as an element electrode.

A scanning signal applying means (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices 64 arranged in the X direction is connected to the X-direction wiring 62.

On the other hand, the Y-direction wiring 63 is connected to a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 64 arranged in the Y-direction according to an input signal. The driving voltage applied to each electron-emitting device is supplied as a difference voltage between the scanning signal and the modulation signal applied to the device.

In the above structure, individual elements can be selected and driven independently by using simple matrix wiring. An image forming apparatus configured by using an electron source having such a simple matrix arrangement will be described with reference to FIG. FIG. 6 is a schematic view showing an example of the display panel of the image forming apparatus according to the present invention.

In FIG. 6, reference numeral 91 is an electron source substrate on which a plurality of electron-emitting devices are arranged, 101 is a rear plate on which the electron source substrate 91 is fixed, and 106 is a fluorescent material as a phosphor which is an image forming member on the inner surface of the glass substrate 103. The face plate is formed with the film 104, the metal back 105, and the like. 1
Reference numeral 02 denotes a support frame, and the rear plate 101 and the face plate 106 are connected to the support frame 102 by using frit glass or the like.

Reference numeral 107 denotes an envelope, which is sealed and formed, for example, by firing in the air or nitrogen in the temperature range of 400 to 500 ° C. for 10 minutes or more.

Reference numeral 94 corresponds to the electron-emitting device in FIG. Reference numerals 92 and 93 denote an X-direction wiring and a Y-direction wiring connected to a pair of electron-emitting devices.

The envelope 107 is composed of the face plate 106, the support frame 102, and the rear plate 101 as described above. Since the rear plate 101 is provided mainly for the purpose of reinforcing the strength of the insulating substrate 91, the electron source substrate 91
Separate rear plate 10 if it has sufficient strength
1 may be unnecessary.

That is, the support frame 102 is directly attached to the electron source substrate 91.
The face plate 106, the support frame 102, and the electron source substrate 91 may be sealed to form the envelope 107.

On the other hand, by installing a support member (not shown) called a spacer between the face plate 106 and the rear plate 101, the envelope 107 having sufficient strength against atmospheric pressure can be constructed. .

In the image forming apparatus using the electron-emitting device of the present invention, the phosphor (fluorescent film 104) is aligned and arranged above the electron-emitting device 94 in consideration of the emitted electron orbit.

FIG. 7 shows the fluorescent film 1 used for the panel of the present invention.
It is a schematic diagram which shows 04. In the case of a color fluorescent film, it is composed of a black conductive material 111 called a black stripe shown in FIG. 7A or a black matrix shown in FIG.

In the case of color display, the purpose of providing the black stripes and the black matrix is to make the color mixture between the phosphors 112 of the three primary color phosphors black so as to make the color mixture less noticeable, It is to suppress the decrease in contrast due to the reflection of external light.

As the material of the black stripe, in addition to a commonly used material containing graphite as a main component, a material having conductivity and little transmission and reflection of light can be used.

As a method for applying the phosphor to the glass substrate 103, a precipitation method, a printing method or the like can be adopted regardless of monochrome or color. A metal back 105 is usually provided on the inner surface side of the fluorescent film 104.

The purpose of providing the metal back is to improve the brightness by specularly reflecting the light toward the inner surface side of the light emission of the phosphor to the face plate 106 side, and to act as an electrode for applying an electron beam accelerating voltage. That is, the fluorescent film 104 is protected from damage due to the collision of negative ions generated in the envelope.

The metal back 105 is produced by performing a smoothing process (usually called “filming”) on the inner surface of the fluorescent film after the fluorescent film is produced, and then depositing Al using vacuum deposition or the like. Can be made.

The face plate 106 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 104 in order to further enhance the conductivity of the fluorescent film 104.

In the present invention, since the electron beam reaches right above the electron-emitting device 94, the fluorescent film 104 is positioned and arranged right above the electron-emitting device 94.

Next, an enclosure (panel) which has been subjected to a sealing step.
The vacuum sealing step of sealing the will be described.

In the vacuum sealing process, the envelope (panel) 107 is used.
While heating at 80 to 250 ° C, the gas is exhausted through an exhaust pipe (not shown) by an exhaust device such as an ion pump or a sorption pump to create an atmosphere with a sufficiently small amount of organic substances, and then the exhaust pipe is burned. Heat to melt and seal.

A getter process may be performed in order to maintain the pressure after the envelope 107 is sealed.

Immediately before or after the envelope 107 is sealed, a predetermined position (not shown) in the envelope 107 is provided by heating using resistance heating or high frequency heating.
This is a process of heating the getter arranged in the above to form a vapor deposition film.

The getter usually has Ba as a main component, and maintains the atmosphere in the envelope 107 by the adsorption action of the vapor deposition film.

In the image forming apparatus constructed by using the electron source of the simple matrix arrangement manufactured by the above steps, the outside-container terminals Dx1 to Dxm, Dy1 to each electron-emitting device are formed.
By applying a voltage via Dyn, electron emission occurs.

Va applies a high voltage to the metal back 105 or the transparent electrode (not shown) via the high voltage terminal 113 to accelerate the electron beam.

The accelerated electrons collide with the fluorescent film 112 and emit light to form an image.

Next, a configuration example of a drive circuit for performing television display based on an NTSC television signal on a display panel constructed by using an electron source having a simple matrix arrangement will be described with reference to FIG. . FIG. 8 is a block diagram of an image forming apparatus using an electron source having a simple matrix arrangement according to the present invention.

In FIG. 8, 121 is an image display panel,
122 is a scanning circuit, 123 is a control circuit, and 124 is a shift register. 125 is a line memory, 126 is a synchronizing signal separation circuit, 127 is a modulation signal generator, Vx and V
a is a DC voltage source.

The image display panel 121 is connected to an external electric circuit via the terminals Dox1 to Doxm, the terminals Doy1 to Doyn, and the high voltage terminal Hv.

To the terminals Dox1 to Doxm, electron sources provided in the display panel, that is, electron-emitting device groups matrix-wired in a matrix of M rows and N columns are sequentially driven row by row (N elements). Scanning signal is applied.

A modulation signal for controlling the output electron beam of each element of the electron-emitting devices in one row selected by the scanning signal is applied to the terminals Dy1 to Dyn. From the DC voltage source Va, for example, 10 k [V] is applied to the high voltage terminal Hv.
Is supplied, which is an accelerating voltage for giving enough energy to excite the phosphor to the electron beam emitted from the electron-emitting device.

The scanning circuit 122 will be described. The circuit is provided with M switching elements inside (schematically shown by S1 to Sm in the figure).

Each switching element selects either the output voltage of the DC voltage source Vx or 0 [V] (ground level) and is electrically connected to the terminals Dx1 to Dxm of the image display panel 121.

Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 123, and can be constructed by combining switching elements such as FETs.

In the case of the present example, the DC voltage source Vx causes the drive voltage applied to the non-scanned element to be equal to or lower than the electron emission threshold voltage based on the characteristics of the electron emission element (electron emission threshold voltage). It is set to output such a constant voltage.

The control circuit 123 has a function of matching the operation of each part so that an appropriate display is performed based on an image signal input from the outside.

The control circuit 123 includes the sync signal separation circuit 12
Based on the synchronization signal Tsync sent from the control unit 6, control signals Tscan, Tsft, and Tmry are generated for each unit.

The sync signal separation circuit 126 is a circuit for separating the sync signal component and the luminance signal component from the NTSC system television signal input from the outside, and uses a general frequency separation (filter) circuit or the like. Can be configured.

The sync signal separated by the sync signal separation circuit 126 is composed of a vertical sync signal and a horizontal sync signal.
Here, for convenience of explanation, it is shown as a Tsync signal.
The luminance signal component of the image separated from the television signal is represented as a DATA signal for convenience. The DATA signal is input to the shift register 124.

The shift register 124 is for converting the DATA signal serially input in time series into serial / parallel conversion for each line of the image, and based on the control signal Tsft sent from the control circuit 123. The control signal Tsft can be said to be the shift clock of the shift register 124.

The serial / parallel converted image data for one line (corresponding to drive data for N electron emission elements) is output from the shift register 124 as N parallel signals Id1 to Idn.

The line memory 125 is a storage device for storing data for one line of an image for a required time, and stores the contents of Id1 to Idn as appropriate in accordance with the control signal Tmry sent from the control circuit 123.

The stored contents are Id'1 to Id'n.
And is input to the modulation signal generator 127.

The modulation signal generator 127 outputs the image data I
It is a signal source for appropriately driving and modulating each of the electron-emitting devices according to each of d'1 to Id'n, and its output signal is sent to the electron-emitting devices in the image display panel 121 through the terminals Doy1 to Doyn. Is applied.

As described above, the electron-emitting device to which the present invention can be applied has the following basic characteristics with respect to the emission current Ie. That is, a clear threshold voltage Vth is required for electron emission.
Therefore, electron emission occurs only when a voltage higher than Vth is applied.

For voltages above the electron emission threshold,
The emission current also changes according to the change in the voltage applied to the element.
From this, when a voltage is applied to this element, for example, no electron emission occurs even if a voltage below the electron emission threshold is applied, but an electron beam is output when a voltage above the electron emission threshold is applied. .

At this time, the intensity of the output electron beam can be controlled by changing the applied voltage Vf.

When a pulse voltage is applied to this device, the electron beam intensity is controlled by changing the pulse height Ph, and the total amount of electron beam charges output is changed by changing the pulse width Pw. It is possible to do

Therefore, as a method of modulating the electron-emitting device according to the input signal, a voltage modulation method, a pulse width modulation method or the like can be adopted.

In carrying out the voltage modulation method, the modulation signal generator 127 generates a voltage pulse of a constant length and appropriately modulates the peak value of the pulse according to the input data. A circuit can be used.

When implementing the pulse width modulation method,
As the modulation signal generator 127, it is possible to use a circuit of a pulse width modulation system that generates a voltage pulse having a constant peak value and appropriately modulates the width of the voltage pulse according to the input data.

The shift register 124 and the line memory 12
The digital signal type 5 and the analog signal type 5 can be adopted.

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 DATA of the sync signal separation circuit 126 into a digital signal. For this, an A / D converter is provided at the output section of the sync signal separation circuit 126. Just go. In connection with this, the circuit used for the modulation signal generator 127 is slightly different depending on whether the output signal of the line memory 125 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 127 uses, for example, a D / A conversion circuit, and an amplification circuit or the like is added if necessary.

In the case of the pulse width modulation method, the modulation signal generator 127 compares the output value of the memory with the output value of the counter and the counter for counting the number of waves output from the oscillator, for example. A circuit is used that is a combination of comparators. If necessary, an amplifier for voltage-amplifying the pulse-width-modulated modulation signal output from the comparator up to the driving voltage of the electron-emitting device can be added.

In the case of the voltage modulation method using an analog signal, the modulation signal generator 127 may be an amplifier circuit using an operational amplifier, for example, and a level shift circuit or the like may be added if necessary.

In the case of the pulse width modulation method, for example, a voltage control type oscillation circuit (VCO) can be adopted, and an amplifier for amplifying the voltage up to the driving voltage of the electron-emitting device can be added if necessary.

In the image display device to which the present invention having such a structure can be applied, by applying a voltage to each electron-emitting device through the terminals Dox1 to Doxm and Doy1 to Doyn outside the container, electron emission is performed. Occurs.

Metal back 10 via high voltage terminal Hv
5 or a high voltage is applied to the transparent electrode (not shown) to accelerate the electron beam. The accelerated electrons collide with the fluorescent film 104 to generate light emission and an image is formed.

The configuration of the image forming apparatus described here is an example of the image forming apparatus to which the present invention can be applied, and various modifications can be made based on the technical idea of the present invention.

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

The image forming apparatus of the present invention can be used not only as a display apparatus for television broadcasting, a display apparatus such as a video conference system and a computer, but also as an image forming apparatus as an optical printer including a photosensitive drum and the like. Can be used.

[0160]

EXAMPLES Examples of the present invention will be described in detail below. [Embodiment 1] An embodiment of the present invention will be described in detail with reference to FIGS. First, in FIG. 4, a cross-sectional view of the electron-emitting device manufactured according to this example is shown together with an example of a manufacturing method. The manufacturing process of the electron-emitting device of this embodiment will be described in detail below.

(Step 1) First, as shown in FIG. 4 (a), quartz is used for the insulating substrate 1 and after sufficiently washing,
As the first electrode 4, Ti having a thickness of 500 nm and an electron emission layer 7 were deposited to a thickness of 100 nm by the sputtering method. The electron emission material of the electron emission layer 7 was diamond-like carbon containing a low resistance diamond film by the CVD method, and the reaction gas was a mixed gas of CH ₄ and H ₂ and oxygen.

(Step 2) Next, as shown in FIG. 4B, spin coating of a positive photoresist (AZ1500 / Clariant) and a photomask pattern are exposed by photolithography, developed, and subjected to electron irradiation. The emission material and the Ti electrode layer were dry-etched with a CF ₄ gas.

(Step 3) As shown in FIG. 4C, as the insulating layer 3, SiO _{2 having} a thickness of 1000 nm and the second electrode 2 are formed.
As a result, Ta having a thickness of 100 nm was deposited in this order, and then patterning was performed in the same manner as in the photolithography of step 2, and holes were formed by dry etching.

(Step 4) As shown in FIG. 4D, the first insulating layer and the first insulating layer are further formed by patterning and etching.
The Ti electrode, which is the electrode layer of, was etched. FIG. 3B is a plan view of the opening shape of the electron emitting portion at this time, and the electron emitting area is large.

The electron-emitting device manufactured as described above was arranged and driven as shown in FIG. 3B. The driving voltage is Vg = 20V, Va = 5kV, the first electrode is 0V, and the electron-emitting device is also 0V.

Distance D3 between electron-emitting device and anode 12
Was 1 mm. Here, using an electrode coated with a phosphor as the anode 12, a large amount of electron emission was confirmed as compared with FIG.

[Embodiment 2] As Embodiment 2, an opening for an electron emitting portion is formed as shown in the plan view of FIG. Figure 9
FIG. 3 is a plan view showing the structure of an electron-emitting device according to the present invention.

Here, a plurality of values are used as the interval values of the electron emitting portions in the first direction. Also, a plurality of values are used as the interval value of the electron emitting portions in the second direction.

It is preferable to lower the resistance by design even if the resistance of the gate electrode is relatively high, the driving frequency is high, and the wiring is long for a large area. As shown in FIG. It is possible to reduce the resistance to the electron-emitting device here by providing a space in the peripheral portion.

Although the number of electron-emitting devices is smaller than that of the first embodiment, the resistance can be further reduced. The effect similar to that of the first embodiment is obtained in that the resistance is lowered in one direction and the electron emission number is secured in the second direction perpendicular to the resistance. The forming method is exactly the same as the example shown in the first embodiment except that the patterning shape is changed, and is not particularly limited.

Further, as described in the embodiment, each material is not limited to various materials.

[Third Embodiment] A third embodiment will be described with reference to FIG. FIG. 10 is a sectional view showing the structure of the electron-emitting device according to the present invention.

FIG. 10 shows the cross-sectional shape of the electron-emitting device, but the electron-emitting film is electrically separated in each electron-emitting device. Hereinafter, the manufacturing process of the electron-emitting device of this embodiment will be described in detail with reference to FIG. FIG. 11 is a diagram showing an example of a method of manufacturing the electron-emitting device according to the third embodiment.

(Step 1) First, as shown in FIG. 11A, quartz is used for the insulating substrate 1 and after sufficiently cleaning,
Ti having a thickness of 500 nm was deposited as the first electrode 4 by the sputtering method.

(Step 2) Next, as shown in FIG. 11B, spin coating of a positive photoresist (AZ1500 / Clariant) and a photomask pattern are exposed and developed by photolithography by Ti. After the electrode layer was dry-etched with a CF ₄ -based gas, the electron emission material 20 was deposited by the CVD method. The electron emission material was diamond-like carbon mainly composed of amorphous carbon, and the reaction gas was a mixed gas of CH ₄ and H ₂ and oxygen.

Then, the electron-emitting material 20 was patterned again in advance by using a photolithography process so that the electron-emitting device was formed into a shape of the hole.

(Step 3) As shown in FIG. 11C, SiO _{2 having} a thickness of 1000 nm is deposited as the insulating layer 3 and Ta having a thickness of 100 nm is deposited as the second electrode 2 in this order. Using a process similar to photolithography, patterning was performed according to the electron emission film separated in step 2, and holes were formed by dry etching and wet etching.

The electron emission films thus formed are completely separated from each other, and the electron films are connected as a resistor. Unlike Examples 1 and 2, there is no electrical interaction. In comparison with the linear structure shown in FIG. 13 (b) of the related art in which a large electron emission area can be obtained, since individual electron emission films are structurally separated by the holes, the influence of adjacent emission points is large. Since the characteristics can be reduced, the desired characteristics can be ideally obtained, and the electron emission area itself can be made large, so that an element very preferable as the characteristics of the electron source can be formed.

[Example 4] An image forming apparatus was produced using the electron-emitting devices of Examples 1 to 3. As an example, a case where the device of Example 1 is used is shown.

The device of Example 1 was replaced with 320 × 240 MTX.
Arranged in a shape. As for the wiring, as shown in FIG. 6, the X side was connected to the first electrode and the Y side was connected to the second electrode. Element is horizontal 300μ
m, and a pitch of 300 μm in the vertical direction, the first direction is defined along the cathode wiring on the X side as shown in FIG. 1, and the gate wiring direction, which is the Y side perpendicular to the first direction, is defined as the second direction. did.

An electron-emitting device was formed only in a 100 μm square area in a 300 μm pixel, the hole diameter was 1 μm, the pitch was 3 μm in the X direction, and 1.5 μm in the Y direction.

A phosphor was arranged on the upper part of the device. As a result, it is possible to form a high-definition image forming apparatus that is capable of matrix driving.

Although the layout is designed using FIG. 1 here, it is needless to say that the layout is not particularly limited. It goes without saying that there is no problem even if the distributions of the electron-emitting devices are different among the first, second, third, and further pixels.

[0184]

As described above, the present invention can provide an electron-emitting device which has a large electron emission area, can be driven by a low resistance wiring, can reduce the electron beam diameter, and can be manufactured easily.

When such an electron-emitting device is applied to an electron source or an image forming apparatus, an electron source and an image forming apparatus having excellent performance can be realized.

[Brief description of drawings]

FIG. 1 is a plan view showing the structure of an electron-emitting device according to the present invention.

FIG. 2 is a sectional view showing a structure of an electron-emitting device according to the present invention.

FIG. 3 is a plan view showing a configuration of an electron-emitting device according to the present invention.

FIG. 4 is a diagram showing a manufacturing method of an embodiment of the electron-emitting device according to the present invention.

FIG. 5 is a schematic configuration diagram showing an electron source having a simple matrix arrangement according to the present invention.

FIG. 6 is a schematic view showing an example of a display panel of the image forming apparatus according to the present invention.

FIG. 7 is a schematic view showing a fluorescent film in the image forming apparatus according to the present invention.

FIG. 8 is a block diagram of an image forming apparatus using an electron source having a simple matrix arrangement according to the present invention.

FIG. 9 is a plan view showing a configuration of an electron-emitting device according to the present invention.

FIG. 10 is a sectional view showing a structure of an electron-emitting device according to the present invention.

FIG. 11 is a diagram showing an example of a method for manufacturing the electron-emitting device according to the third embodiment.

FIG. 12 is a cross-sectional view schematically showing an example of a conventional Spindt type electron-emitting device.

FIG. 13 is a plan view schematically showing a plane of a conventional electron-emitting device.

FIG. 14 is a diagram schematically showing a conventional image forming apparatus.

[Explanation of symbols]

1 Insulating substrate 2 Second electrode 3 insulating layers 4 First electrode 6 equipotential surface 7 Electron emission layer 8 hole pattern 10 Insulating substrate 12 Anode 13 Phosphor 14,17 Electron emission layer 20 electron emission materials 21 Gate electrode layer 30 insulating layer 40 cathode electrode layer 50 microchips 60 equipotential surface 61 electron source substrate 62 X-direction wiring 63 Y direction wiring 64 electron-emitting device 91 electron source substrate 92 X-direction wiring 93 Y direction wiring 94 Electron emitting device 101 rear plate 102 support frame 103 glass substrate 104 fluorescent film 105 metal back 106 face plate 107 envelope 111 Black conductive material 112 phosphor 113 high voltage terminal 121 Image display panel 122 scanning circuit 123 Control circuit 124 shift register 125 line memory 126 Synchronous signal separation circuit 127 Modulation signal generator

Claims (12)

[Claims] 1. A first conductive layer formed on an insulating substrate or a first insulating layer, a second insulating layer laminated on the first conductive layer, and a first conductive layer formed on the first conductive layer. A second conductive layer laminated on the second insulating layer, and a substantially circular opening formed on the first conductive layer from the second insulating layer to the second conductive layer And an electron emission layer that includes an electron emission material and is laminated on the first conductive layer in the opening, the first conductive layer and the second conductive layer. An electron-emitting device that emits electrons from the electron-emitting layer in the circular opening when a voltage is applied between the electron-emitting layer and the conductive layer, the plurality of electron-emitting portions having the opening in one pixel. And the distance between the openings in the second direction perpendicular to the first direction is larger than the distance between the openings in the first direction. An electron-emitting device characterized by the following. 2. The distance between openings in the first direction is one or more, and the distance between openings in the second direction is also one or more, and the distance between openings in the first direction. 2. The electron-emitting device according to claim 1, wherein the maximum distance is less than the minimum distance between the openings in the second direction. 3. The electron-emitting device according to claim 1, wherein the distance between the openings in the first direction is not larger than the diameter of the openings. 4. The electron-emitting device according to claim 1, wherein the diameter of the opening is smaller than 5 μm. 5. The electron emitting device according to claim 1, wherein the electron emitting layer is separated between the openings. 6. The electron emitting device according to claim 1, wherein the electron emitting layer contains carbon. 7. The electron-emitting device according to claim 6, wherein the electron-emitting layer contains amorphous carbon, diamond-like carbon or diamond. 8. A first conductive layer, an insulating layer arranged on the first conductive layer and having a plurality of openings, and arranged on the insulating layer and arranged on the first conductive layer. A second conductive layer having a plurality of openings communicating with each of the plurality of openings formed, and a first conductive layer located in each opening arranged in the insulating layer. An electron emission layer, and a voltage is applied between the first conductive layer and the second conductive layer to emit electrons from the electron emission layer in the opening. An electron emitting device, wherein the plurality of inter-aperture distances in a second direction perpendicular to the first direction are larger than the plurality of inter-aperture distances in the first direction. 9. An electron source, wherein the electron-emitting devices according to claim 1 are arranged in a matrix. 10. The electron source according to claim 9, wherein the first direction and the second direction are along the matrix wiring. 11. An image forming apparatus, comprising: the electron source according to claim 9 or 10; and an image forming member that forms an image by electrons emitted from the electron source. 12. The image forming member is a phosphor that emits light upon collision of electrons.
The image forming apparatus according to item 1.