JP2003100200A - Electron emission element, electron source, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emission element capable of obtaining a sufficient emission current, reducing scattering of an electron beam on a side wall of an opening, reducing a beam diameter of an emission electron, and maintaining a beam diameter as a pixel to be small, and enabling to manufacture easily. SOLUTION: The electron emission element is structured by forming a gate electrode 14 and a cathode electrode 12 on a substrate 11, and a focusing electrode 16 on the same plane with the cathode electrode 12 or closer to the substrate 11. A space W2 between the cathode electrode 12 and the focusing electrode 16 is narrower at a pixel end part than at a pixel center part.

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, as this type of technology, two types of electron-emitting devices are known, which are a thermoelectron-emitting device and a cold cathode electron-emitting device. The cold cathode electron-emitting device includes a field emission type (hereinafter referred to as “FE type”), metal /
There are an 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, WP Dyke & W.W.
Dolan, "Field Emission", Advancein Electron Physic
s, 8,89 (1956) and CA Spindt, "PHYSICAL Propertie
s ofthin-film field emission cathodes with molybd
enium cones ", J. Appl. Phys., 47, 5248 (1976), etc.
Alternatively, JP-A-8-96703 and JP-A-8-967
04, JP-A-8-115654, and JP-A-10-12.
Those disclosed in 5215 and the like are known.

As an example of preventing the spread of the electron beam emitted from the electron emitting portion, a focusing electrode is provided above the electron emitting portion and between the electron emitting portion and the anode.
No. 266787 and Japanese Patent Laid-Open No. 11-3
The one disclosed in 29308 is known.

[0005]

In order to apply the electron-emitting device to an image forming apparatus such as a display, it is necessary to have an emission current that causes the phosphor to emit light with sufficient brightness. Further, in order to increase the definition of the display, it is necessary that the diameter of the electron beam with which the phosphor is irradiated is small. And it is important to be easy to manufacture.

CA Spind, which is an FE type electron-emitting device
t, "PHYSICAL Properties of thin-film field emissio
n cathodes with molybdenium cones ", J. Appl. Phy
In the example disclosed in s., 47, 5248 (1976), etc., a microchip is generally formed as an emission point and electrons are emitted from the tip of the microchip. Therefore, the electrons emitted from the tip of the microchip may fly out radially, and when they are irradiated on the anode, the diameter of the electron beam may increase. Further, since it is difficult to uniformly manufacture the devices, it is difficult to make the electron emission characteristics uniform among the devices. 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 strongly emit light, thermal destruction of the electron emission portion is induced and the life of the device is limited. Could be. In addition, the ions existing in a vacuum may sputter the tip of the microchip intensively to shorten the life of the device.

In order to improve the performance of such an FE type electron-emitting device, various examples have been proposed as individual solutions.

As an example of reducing the spread of the electron beam, there is an example in which a focusing electrode is arranged above the electron emitting portion and between the electron emitting portion and the anode. In this example, the emitted electron beam is narrowed down by the negative potential of the focusing electrode, but it is very difficult to maintain an accurate distance between the electron emitting portion and the focusing electrode, and the electron emitting portion and the focusing electrode are Positioning is difficult. In addition, the manufacturing process becomes more complicated and the manufacturing cost increases.

Another example of reducing the spread of the electron beam is disclosed in Japanese Patent Laid-Open No. 5-266787. In this example, one or more control electrodes insulated from the gate electrode are provided on the same layer as the gate electrode, and a voltage is applied to the control electrode to generate minute point electrons on the same plane as the gate electrode. The electron beam emitted from the source is controlled to have a desired shape.

As another example of reducing the spread of the electron beam, there are JP-A-8-96703 and JP-A-8-9.
There is one disclosed in Japanese Patent No. 6704.

An example disclosed in Japanese Patent Laid-Open No. 8-96704 is shown in FIG. In this example, a cathode electrode 302 and a gate electrode 304 are laminated on a substrate 301 with an insulating layer 303 interposed therebetween, and openings penetrating the gate electrode 304 and the insulating layer 303 are formed, and an electron emission film is formed in the openings. 305 is an electron-emitting device. Electrons are emitted from the electron emission film 305 by applying a voltage higher than that of the cathode electrode 302 to the gate electrode 304.

At this time, since the equipotential surface formed inside the opening becomes substantially flat on the electron emission film, the diameter of the electron beam when it reaches the anode is reduced. In these examples, by using a material with a low work function as the electron emission film, it is possible to emit electrons even if the tip is not sharp like a microchip, and at the same time, it is relatively manufactured. easy. Further, since electrons are emitted from the entire surface of the electron emission film, there is an advantage that a problem such as chip breakage does not occur and the life is long.

Strictly speaking, however, the equipotential surface formed in the opening has a convex shape depending on the thickness of the electron emission film 305, and is most prominent at the peripheral portion of the opening on the surface of the electron emission film 305. A strong electric field is applied. For this reason, the electrons are mainly emitted from the peripheral portion of the opening in the surface of the electron emission film 305, and the equipotential surface in the opening has a convex shape.
Many electrons collide with the sidewall of the opening. As a result, electrons may enter the insulating layer, which may cause a problem such as discharge due to charge-up.

Further, as compared with the above example, examples in which the scattering of electrons on the side wall of the opening is suppressed and the diameter of the electron beam is made smaller are also disclosed in JP-A-8-115654 and JP-A-10-1252.
No. 15, for example.

FIG. 14 shows an example disclosed in Japanese Patent Laid-Open No. 8-115654. In this example, a cathode electrode 302 and a gate electrode 304 are laminated on a substrate 301 with an insulating layer 303 interposed therebetween, and the gate electrode 304 and the insulating layer 303 are respectively penetrated, and a part of the cathode electrode 302 is also dug, Forming an opening. An electron emission film 305 is provided in the opening such that the surface of the electron emission film 305 is deeper than the joint surface between the cathode electrode 302 and the insulating layer 303.
The electron emitting portion is formed. Also in this example, by applying a voltage higher than that of the cathode electrode 302 to the gate electrode 304, electrons are emitted from the electron emission film 305. At this time, the equipotential surface formed in the opening is the digging depth of the cathode electrode 302 and the electron emission film 3.
The film becomes concave depending on the film thickness of 05, etc., and the risk of charge-up of the insulating layer due to the incidence of electrons is reduced, and the electron beam diameter when reaching the anode is also reduced.

However, in order to arrange a plurality of electron-emitting devices shown in this example in one pixel so that the emitted electrons are more focused in the central portion of the pixel and the electron beam diameter as the pixel is made smaller, As approaching the end of the pixel, the bottom surface of the opening formed by engraving the cathode electrode 302 must be sloped, which may complicate the structure and make manufacturing difficult. .

Another example of reducing the spread of the electron beam is disclosed in Japanese Patent Application Laid-Open No. 11-329308.

An example disclosed in Japanese Patent Laid-Open No. 11-329308 is shown in FIG. In this example, the cathode electrode 302 and the gate electrode 304 are formed on the substrate 301 by the insulating layer 303a.
And a gate electrode 304 and an insulating layer 303 which are stacked with each other.
Apertures are formed so as to penetrate through each of a, and a focusing electrode 306 is stacked in the opening with an insulating layer 303b interposed therebetween, and an electron emission material 305 is provided so as to cover the focusing electrode 306 and the insulating layer 303b. It is an electron-emitting device. By applying a voltage higher than that of the cathode electrode 302 to the gate electrode 304,
Electrons are emitted from the electron emission material 305. At this time, the focusing electrode 306 is connected to the cathode electrode 302.
A voltage higher than the gate electrode 304 and lower than the gate electrode 304 is applied.

At this time, the equipotential surface formed in the opening is
The relationship between the magnitude of the voltage applied to the focusing electrode 306 and the magnitude of the voltage applied to the gate electrode 304, and the insulating layer 3
03b and the thickness of the focusing electrode 306 and the insulating layer 3
Depending on the thickness relation of 03a, etc., it becomes a concave shape, the risk of charge-up of the insulating layer due to the incidence of electrons is reduced, and the electron beam diameter when reaching the anode is also reduced.

However, in order to arrange the plurality of electron-emitting devices shown in this example in one pixel so that the emitted electrons are more concentrated in the central portion of the pixel and the electron beam diameter of the pixel is made smaller, As the position of the focusing electrode 306 is closer to the pixel end, the focusing electrode 306 must be provided in a position closer to the pixel end than in the opening, which may complicate the structure and make manufacturing difficult. .

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a sufficient emission current and reduce the scattering of electron beams on the side wall of the opening. An object of the present invention is to provide an electron-emitting device capable of reducing the beam diameter of emitted electrons and keeping the beam diameter of a pixel small and easily manufactured.

[0022]

In order to achieve the above object, a first aspect of the present invention is to provide a first electrode, a second electrode insulated from the first electrode, and a second electrode on a substrate. An electron-emitting material provided on the second electrode to form an electron-emitting portion, and a third electrode insulated from the first electrode and the second electrode. The voltage, which is provided on the same plane as the second electrode or closer to the substrate, and is applied when driving the electron-emitting device, is the voltage applied to the first electrode, the second electrode, and the third electrode. It is characterized in that the electrodes are larger in order.

A second invention is characterized in that the third electrode is insulated from the first electrode and the second electrode through an insulating layer.

A third invention is characterized in that a plurality of the electron emitting portions are arranged.

A fourth invention is the second electrode and the third electrode.
The distance between the electrode and the electrode differs depending on the electron emitting portion.

A fifth invention is that the second electrode and the third electrode.
In the direction in which the plurality of electron emitting portions are arranged among the plurality of electron emitting portions, the distance from the electrode becomes narrower toward the end portion.

A sixth aspect of the invention is characterized in that the electron emitting material is a thin film.

A seventh invention is characterized in that the electron emitting material is substantially flat.

The eighth invention is characterized in that the electron-emitting material contains carbon.

A ninth aspect of the invention is an electron source, wherein a plurality of the electron-emitting devices are arranged in parallel and connected to each other, and at least one line of the electron-emitting devices is provided.

A tenth aspect of the present invention has at least one row of the electron-emitting devices in which a plurality of the electron-emitting devices are arranged, and the first electrodes and the electric electrodes are connected to drive the electron-emitting devices. Electrically connected to each other and the second electrode electrically connected to the second electrode are arranged in a matrix, and electrically connected to the third electrode third electrode. It is an electron source characterized by the presence of wiring.

An eleventh invention is an electron source characterized in that the third wiring is arranged in parallel with the second wiring.

A twelfth aspect of the invention is provided with the electron source and an image forming member for forming an image by the electrons emitted from the electron source, wherein the electron amount of each electron-emitting device of the electron source is determined by an information signal. The image forming apparatus is characterized by being controlled.

A thirteenth invention is the image forming apparatus wherein the image forming member is a phosphor.

[0035]

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 electron-emitting device according to this embodiment is characterized in that the first electrode, the second electrode insulated from the first electrode, and the electron provided on the second electrode are provided on the substrate. And a third electrode having an emitting material and insulated from the first electrode and the second electrode on the same plane as the second electrode or on the substrate side.

In the electron-emitting device according to the present embodiment having such a configuration, the third electrode provided on the same plane as the second electrode which is the cathode electrode or on the substrate side of the second electrode is connected to the cathode electrode. By applying a low potential, the equipotential surface formed between the gate electrode, which is the first electrode, and the cathode electrode becomes concave, and the electrons emitted from the electron-emitting material enter the insulating layer, The risk of charging up the insulating layer can be reduced, and the beam diameter of electrons when reaching the anode, which is the anode, can be reduced.

When the place where the electrons are emitted is closer to the surface of the cathode electrode, that is, when the electron emitting material is a thin film, the third electrode which is the focusing electrode is on the same plane as the cathode electrode. Alternatively, when the position is closer to the substrate, electrons can be affected immediately after being emitted from the electron-emitting material, so that the effect is more effective than when the focusing electrode is on the same plane as the gate electrode. large.
In addition, the present invention can exert the influence of the focusing electrode on the emitted electrons more than when the focusing electrode is between the gate electrode and the anode.

By changing the distance between the focusing electrode and the cathode electrode within the pixel, that is, by narrowing the distance between the focusing electrode and the cathode electrode, whichever is closer to the end of the pixel. By this, the shape of the equipotential surface formed between the gate electrode and the cathode electrode becomes asymmetric, and the emitted electrons are more concentrated in the central portion of the pixel, and the diameter of the electron beam as the pixel can be made smaller. . Therefore, the pixel area that can be used for electron emission can be made wider, and more emission current can be obtained. When the focusing electrode is on the same plane as the cathode electrode, the focusing electrode and the cathode electrode can be produced in the same process, so that the distance between the focusing electrode and the cathode electrode can be produced with better control.

FIG. 1 is a schematic plan view of an electron-emitting device manufactured according to this embodiment, and FIG. 2 is a line A--A in FIG.
An example of the schematic perspective view by a line is shown.

In FIGS. 1 and 2, 11 is a substrate and 12 is
Is a cathode electrode, 13a and 13b are insulating layers, 14 is a gate electrode, 15 is an electron emission film, 16 is a focusing electrode, W1 is an opening width, and W2 is a distance between the cathode electrode and the focusing electrode.

The opening width W1 and the distance W2 between the cathode electrode and the focusing electrode depend on the work function of the material forming the device and the material of the electron emission film 15, the voltage for driving, the shape of the emitted electron beam required, and the like. It is set appropriately. Usually, it is set in the range of several tens nm to several tens of μm, preferably several hundreds n.
It is selected in the range of m to several μm. Further, the opening width W1 and the distance W2 between the cathode electrode and the focusing electrode may be different in size or the same in one pixel. Further, the thickness and width of each material forming the electron-emitting device can be arbitrarily selected to be suitable values depending on the intended use.

The element according to the present embodiment shown in FIG.
The cathode electrode and the gate electrode are laminated on the substrate with the insulating layer interposed therebetween, and the openings penetrating the gate electrode and the insulating layer are formed, and the electron emission film is provided in the opening. This is an electron-emitting device in which a focusing electrode is provided on the same plane via an insulating layer. By applying a voltage higher than that of the cathode electrode to the gate electrode, electrons are emitted from the electron emission film, and by applying a voltage lower than that of the cathode electrode to the focusing electrode,
The electrons emitted from the electron emission film 15 enter the insulating layer,
The risk of charge-up of the insulating layer is reduced, and the diameter of the electron beam is reduced.

FIG. 3 is a schematic view showing a state of an equipotential surface within a certain opening when a voltage is applied to the gate electrode and the focusing electrode to drive the same.

In FIG. 3, reference numeral 17 denotes an equipotential surface inside the opening.

The equipotential surface 17 changes depending on the relationship between the voltages applied to the gate electrode and the focusing electrode, the distance between the cathode electrode and the focusing electrode, and the thickness of the insulating layer. As shown in FIG. The electron is emitted from the electron emission film in the direction toward the center of the opening. Therefore, the risk of charge-up of the insulating layer due to the incidence of electrons can be reduced, and the beam diameter of the electrons when reaching the anode can be reduced.

2 and 3, only the electron emitting portion is shown, but when driving the electron emitting device of the present invention, the anode for attracting electrons emitted from the electron emitting portion faces the electron emitting portion. Set up.

The electron-emitting device of the present invention described above will be described in detail with reference to more preferable embodiments. Figure 4
FIG. 4 is a schematic cross-sectional view showing an example of a method for manufacturing an electron emitting portion of an electron emitting device according to this embodiment.

First, as shown in FIG. 4A, the substrate 11
An insulating layer 13a is laminated on top. The surface of which is thoroughly cleaned in advance, quartz glass, glass with a reduced content of impurities such as Na, soda lime glass, a laminated body in which SiO ₂ is laminated on a silicon substrate, etc. by a sputtering method, insulation of ceramics such as alumina One of the substrates is the substrate 11
The insulating layer 13a is laminated on the substrate 11.

The insulating layer 13a is formed by sputtering, CVD (C
(hemal vapor Deposition)
It is formed by a general vacuum film forming method such as a vapor deposition method or a vapor deposition method, and its thickness is set in the range of several tens nm to several μm, preferably selected from the range of several hundred nm to several μm. Preferred materials are SiO ₂ , SiN, Al
_A material having a high breakdown voltage capable of withstanding a high electric field such as ₂ O ₃ , Ta ₂ O ₅ , and CaF is desirable.

Next, as shown in FIG. 4B, the insulating layer 1
A mask pattern 18a is formed on 3a by a photolithography technique. The mask pattern 18a is formed except a portion which is etched to form an opening in the next process.

Then, as shown in FIG. 4C, an opening is formed in the insulating layer 13a. The opening is formed by etching, and the main etching process may be performed so as to penetrate the insulating layer 13a or may be stopped in the middle of the insulating layer 13a. The present etching method may be selected according to the material of the insulating layer 13a to be etched.

As shown in FIG. 4D, the mask pattern 18a is removed.

Then, as shown in FIG. 4E, the cathode electrode 12 and the focusing electrode 16 are laminated.

The cathode electrode 12 and the focusing electrode 16 are generally conductive and are formed by a general vacuum film forming technique such as a vapor deposition method and a sputtering method. The material of the cathode electrode line 12 is, for example, Be, Mg, Ti, Zr, H.
f, V, Nb, Ta, Mo, W, Al, Cu, Ni, C
Metal or alloy material such as r, Au, Pt, Pd, Ti
Carbides such as C, ZrC, HfC, TaC, SiC, WC, HfB ₂ , ZrB ₂ , LaB ₆ , CeB ₆ , YB ₄ , G
It is appropriately selected from borides such as dB ₄ , nitrides such as TiN, ZrN and HfN, semiconductors such as Si and Ge, organic polymer materials and the like. The thickness of the cathode electrode 12 is several tens of n
It is set in the range of m to several mm, and is preferably selected in the range of several hundred nm to several μm.

Then, as shown in FIG. 4F, a shape is formed in which the cathode electrode 12 and the focusing electrode 16 are insulated by the insulating layer 13a. CMP (Chemical
The excess cathode electrode 12 and the focusing electrode 16 deposited on the insulating layer 13a are removed by a mechanical polishing method or the like.

Subsequently, as shown in FIG. 4G, the insulating layer 1
3b and the gate electrode 14 are laminated. The insulating layer 13b is
It is formed by a general vacuum film forming method such as a sputtering method, a CVD method, or a vapor deposition method, and its thickness is several nm to several μm.
Is set in the range of, and preferably selected from the range of several tens nm to several hundreds nm. SiO ₂ is a preferable material,
A material having a high breakdown voltage capable of withstanding a high electric field such as SiN, Al ₂ O ₃ , Ta ₂ O ₅ , and CaF is desirable.

The insulating layer 13a and the insulating layer 13b may be made of the same material or different materials, and may be formed by the same method or different methods.

Further, following the insulating layer 13b, the gate electrode 1
4 is deposited. The gate electrode 14 has conductivity similarly to the cathode electrode 12 and the focusing electrode 16, and the vapor deposition method,
It is formed by a general vacuum film forming technique such as a sputtering method or a photolithography technique. The material of the gate electrode 14 is
For example, Be, Mg, Ti, Zr, Hf, V, Nb, T
a, Mo, W, Al, Cu, Ni, Cr, Au, Pt,
Metal or alloy material such as Pd, TiC, ZrC, Hf
Carbides such as C, TaC, SiC, WC, HfB2, Zr
It is appropriately selected from borides such as B2, LaB6, CeB6, YB4 and GdB4, nitrides such as TiN, ZrN and HfN, semiconductors such as Si and Ge, organic polymer materials and the like. The thickness of the gate electrode 14 is set in the range of several nm to several tens μm, and preferably selected in the range of several tens nm to several μm.

The gate electrode 14 and the cathode electrode 12
The focusing electrode 16 may be made of the same material or different materials,
Further, the same forming method or different methods may be used.

Next, as shown in FIG. 4H, a mask pattern 18b is formed on the gate electrode 14 by a photolithography technique. The mask pattern 18b is
It is formed except for a portion which is etched to form an opening in the next step. Here, in the next step, the insulating layer 13b is formed.
Also, when the opening penetrating the gate electrode 14 is formed, the shape is exactly aligned with the end of the cathode electrode 12, but it may be slightly shifted. In addition, in the next step, the insulating layer 1
When the opening penetrating 3b and the gate electrode 14 is formed, the insulating layer 13b and the gate electrode 14 may cover a part of the cathode electrode 12 or a part of the insulating layer 13a may be visible. . Preferably, in the next step, the insulating layer 1
When the opening penetrating 3b and the gate electrode 14 is formed, the center of the opening and the center of the cathode electrode 12 are preferably aligned with each other.

Then, as shown in FIG. 4I, an opening penetrating the insulating layer 13b and the gate electrode 14 is formed.

The opening is formed by etching,
This etching process may be stopped on the cathode electrode 12, or the cathode electrode 12 and, in some cases, the insulating layer 13a may be removed. The present etching method may be selected according to the materials of the insulating layer 13b and the gate electrode 14 and the cathode electrode 12 and the insulating layer 13a which are the etching targets.

Subsequently, as shown in FIG. 4J, the electron emission film 15 is deposited. The electron emission film 15 is formed by a general vacuum film forming technique such as a CVD method, a vapor deposition method, and a sputtering method. The material of the electron emission film 15 is, for example, graphite,
Fullerene, carbon nanotubes, amorphous carbon, diamond-like carbon, diamond-dispersed carbon and carbon compounds are appropriately selected. A carbon compound having a low work function is preferable. Electron emission film 1
The film thickness of 5 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.

Finally, as shown in FIG. 4K, the mask pattern 18b is removed and the electron-emitting device is completed.

An application example to which the electron-emitting device according to this embodiment is applied will be described below. By arranging a plurality of the electron-emitting devices according to the present embodiment on a substrate, for example, an electron source or an image forming apparatus can be configured.

An electron source obtained by arranging a plurality of electron-emitting devices of the present invention will be described with reference to FIG.

Reference numeral 120 is an electron source substrate, 121 is a focusing electrode wiring, 122 is a cathode electrode wiring, 123 is a gate electrode wiring, 124 is an electron-emitting device of the present invention, and 125 is a connection.

The focusing electrode wiring 121 includes Df1, Df2,
It can be formed of a conductive metal or the like, which is composed of m wirings and is 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 cathode electrode wiring 122 has Dc1 and Dc.
2, ... Consisting of m wirings of Dcn, focusing electrode wiring 12
It is formed similarly to 1.

The gate electrode wiring 123 has Dg1 and Dg
2, ... Dgn consisting of n wires and focusing electrode wire 12
It is formed similarly to 1.

These m focusing electrode wirings 121, m cathode electrode wirings 122, and n gate electrode wirings 1
An interlayer insulating layer (not shown) is provided between the electrodes 23 and 23 to electrically separate the two. Here, both m and n are positive integers.

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. The thickness, material, and manufacturing method of the interlayer insulating layer (not shown) are appropriately set so as to withstand the potential difference at the intersection of the focusing electrode wiring 121, the cathode electrode wiring 122, and the gate electrode wiring 123. The focusing electrode wiring 121, the cathode electrode wiring 122, and the gate electrode wiring 123 are drawn out as external terminals.

Focusing electrodes 16, cathode electrodes 12, and gate electrodes 14 (not shown), which are the electrode layers constituting the electron-emitting device 124, are respectively provided with m focusing electrode wirings 12.
The 1 and m cathode electrode wirings 122 and the n gate electrode wirings 123 are electrically connected to each other by connection lines 125 made of a conductive metal or the like.

Focusing electrode wiring 121, cathode electrode wiring 1
The constituent materials of 22, the gate electrode wiring 123, the connection 125, and the device electrode may be the same or different in some or all of their constituent elements.

These materials are appropriately selected, for example, from the materials of the cathode electrode 12, the gate electrode 14 and the focusing electrode 16 which are the device electrodes of the electron-emitting device 124 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. Further, the device electrode can be used as a wiring electrode.

The focusing electrode wiring 121 is connected to the cathode electrode 12.
Connected to a voltage application device that gives a lower voltage than
It is only necessary to apply a certain voltage. Further, the cathode electrode wiring 122 has electron emission devices 1 arranged in the X direction.
A scanning signal applying means (not shown) for applying a scanning signal is connected to select 24 rows. On the other hand, the gate electrode wiring 123 is connected with a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 124 arranged in the Y direction according to an input signal. The drive voltage applied to each electron-emitting device 124 is supplied as a difference voltage between the scanning signal and the modulation signal applied to the electron-emitting device 124.

In the above structure, individual electron-emitting devices 124 can be selected and driven independently by using simple matrix wiring.

An image forming apparatus constructed by using an electron source having such a simple matrix arrangement will be described with reference to FIG. FIG. 11 is a schematic view showing an example of the display panel of the image forming apparatus.

Reference numeral 120 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged, 131 denotes a rear plate to which the electron source substrate 120 is fixed, 136 denotes an inner surface of a glass substrate 133, and a fluorescent film 134 as a fluorescent substance which is an image forming member and a metal. Back 135
Etc. is a face plate on which are formed.

Reference numeral 132 denotes a support frame, and the rear plate 131 and the face plate 136 are connected to the support frame 132 by using frit glass or the like.

Reference numeral 137 denotes an envelope, which is, for example, in the atmosphere or nitrogen in a temperature range of 400 to 500 degrees.
By firing for more than a minute, it is sealed and configured.

The rear plate 131 is mainly used for the base 12.
Since it is provided for the purpose of reinforcing the strength of 0, the base 12
If 0 itself has sufficient strength, the separate rear plate 131 can be omitted. That is, the support frame 132 is directly sealed to the base 120, and the face plate 136,
The envelope 137 may be configured by the support frame 132 and the base body 120.

On the other hand, by installing a support member (not shown) called a spacer between the face plate 136 and the rear plate 131, it is possible to construct the envelope 137 having sufficient strength against atmospheric pressure. I can.

In the image forming apparatus using the electron-emitting device of the present invention, the phosphor (fluorescent film 134) is aligned and arranged above the electron-emitting device 124 in consideration of the emitted electron trajectory.

FIG. 12 is a schematic diagram showing the fluorescent film 134 used in the panel of the present case. In case of color fluorescent film,
A fluorescent film 134 is composed of a black conductive material 141 called a black stripe shown in FIG. 12A or a black matrix shown in FIG.

The image forming apparatus as described above is used as an image forming apparatus as an optical printer constituted by using a photosensitive drum or the like, in addition to a display apparatus for television broadcasting, a display apparatus such as a video conference system or a computer. Can also be used.

[0088]

EXAMPLES Examples of the present embodiment will be described in detail below.

[Embodiment 1] FIG. 1 is a schematic plan view of an electron-emitting device manufactured according to Embodiment 1, and FIG.
An example of a schematic perspective view taken along the line A'and FIG. 4 show an example of a method for manufacturing the electron-emitting device of this example.

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

(Step 1) First, as shown in FIG. 4A, quartz is used for the substrate 11, and after sufficient cleaning, a 1 μm thick insulating layer 13 a is formed on the substrate 11 by the sputtering method. SiO ₂ was deposited.

(Step 2) Next, as shown in FIG. 4B, spin coating of a positive photoresist (AZ1500 / made by Clariant) and exposure and development of a photomask pattern are performed by photolithography to form a mask pattern. 18a was formed. The mask pattern 18a is formed except for the portion which is dry-etched to form an opening in the next step.

(Step 3) Then, as shown in FIG. 4C, the insulating layer 13a is dry-etched by using CF4 with the mask pattern 18a as a mask.
An opening was formed through a. In this embodiment, the opening has a substantially rectangular shape, the opening width W1 is 1 μm, and the distance W2 between the cathode electrode 12 and the focusing electrode 16 is 400 nm.

(Step 4) Next, as shown in FIG. 4D, the mask pattern 18a was completely removed.

(Step 5) Subsequently, as shown in FIG. 4E, Ta having a thickness of about 1.5 μm was laminated as the cathode electrode 12 and the focusing electrode 16 by the sputtering method.

(Step 6) Then, as shown in FIG. 4F, the extra cathode electrode 12 and the focusing electrode 16 deposited on the insulating layer 13a were removed by the CMP method.

(Step 7) Next, as shown in FIG. 4G, the insulating layer 13a, the cathode electrode 12 and the focusing electrode 16 are formed.
An insulating layer 13b having a thickness of 1 μm is formed thereon by the sputtering method.
m of SiO ₂ and Ta having a thickness of 100 nm as the gate electrode 14 were deposited in this order.

(Step 8) Next, as shown in FIG. 4H, spin coating of a positive photoresist (AZ1500 / manufactured by Clariant), exposure and development of a photomask pattern are performed by photolithography, and a mask pattern is obtained. 18b was formed. The mask pattern 18b is formed except for a portion which is dry-etched to form an opening in the next step.

(Step 9) Then, as shown in FIG. 4I, Cl ₂ and C are used with the mask pattern 18b as a mask.
Insulating layer 1 using F ₄ , CHF ₃ , Ar, and O ₂ gas
3b and the gate electrode 14 were dry-etched, the etching was stopped at the cathode electrode 12, and an opening penetrating the insulating layer 13b and the gate electrode 14 was formed.

(Step 10) Next, as shown in FIG.
As shown in (j), as the electron emission film 15, a diamond-like carbon film was deposited on the bottom surface of the opening by about 50 nm. As the reaction gas, a mixed gas of CH ₄ , H ₂ and N ₂ was used.

(Step 11) Finally, as shown in FIG. 4K, the mask pattern 18b was completely removed to complete the electron-emitting device of this example.

The electron-emitting device manufactured as described above was arranged as shown in FIG. 5 to emit electrons. here,
19 is an anode, Va is a cathode electrode 12 and an anode 1
9 is a potential difference between the gate electrode 14 and the cathode electrode 1.
2 is the potential difference from V2, Vf is the focusing electrode 16 and the cathode electrode 12.
And D1 is the distance between the gate electrode 14 and the anode 19. The electrons emitted from the electron emission film 15 by the electric field formed by Vg are attracted to the anode 19 by Va.

In this embodiment, Va = 5 kV and Vg = 20.
V and D1 = 1 mm. A device capable of measuring a current was placed between the gate electrode 14 and the cathode electrode 12, and the gate current at the time of electron emission was measured. Further, an electrode coated with a phosphor was used as the anode 19, and the electron beam diameter was observed. The gate current mentioned here is a current flowing between the gate electrode 14 and the cathode electrode 12 at the time of electron emission. In addition, the electron beam diameter referred to here is a size up to 10% of the peak luminance of the phosphor that has emitted light.

Focusing electrode 1 having the same pixel size as that of this embodiment
Vf is 2V, 4V, 6 when compared with one that does not have 6 and has the cathode electrode 12 on one surface on the substrate 11 in the pixel.
The gate currents at V, 8V, and 10V decreased to about 97%, 41%, 27%, 3%, and 1% or less, respectively.

It is considered that the electrons emitted from the electron emission film 15 collide with the gate electrode 14 as the gate current increases, and therefore the insulating layer 13b between the gate electrode 14 and the cathode electrode 12 is formed. It is thought that it has collided with. If the gate current flows, power consumption increases, and if the emitted electrons collide with the insulating layer 13b, a problem such as discharge due to charge-up of the insulating layer may occur. It is desirable that the gate current is small.

Further, the electron beam diameters when Vf is 2 V, 4 V, 6 V, 8 V, and 10 V are about 99%, 93%, and 82, respectively, as compared with the case where the focusing electrode 16 is not provided.
%, 58%, and 29%. The smaller the electron beam diameter, the higher the definition becomes possible when used in an image forming apparatus or the like. Therefore, the smaller electron beam diameter is desirable.

[Embodiment 2] FIG. 6 is a schematic plan view of an electron-emitting device manufactured according to Embodiment 2, and FIG. 7 is a schematic perspective view taken along the line AA ′ in FIG.

This embodiment shows an example in which the focusing electrode is provided closer to the substrate than the cathode electrode. Here, only the characteristic part of the present embodiment will be described, and redundant description will be omitted.

(Step 1) First, as shown in FIG. 8A, after using quartz for the substrate 11 and performing sufficient cleaning, a focusing electrode 16 having a thickness of 1 μm was formed on the substrate 11 by a sputtering method. Ti was laminated. Then, by the sputtering method,
The insulating layer 13 has a thickness of 1 μm, SiN, and the gate electrode 14
As a result, 100 nm thick Al was deposited in this order.

(Step 2) Next, as shown in FIG. 8B, the spin coating of a positive photoresist (AZ1500 / Clariant) and the photomask pattern are exposed and developed by photolithography to form a mask pattern. 18 was formed. The mask pattern 18 is formed except for a portion which is dry-etched to form an opening in the next step. In this embodiment, the opening has a substantially rectangular shape, and the opening width W1 is 0.5 μm.

(Step 3) Then, as shown in FIG.
Then, using the mask pattern 18 as a mask, Cl _Two, CF
_Four, CHF_Three, Ar, and O_TwoInsulating layer 1 using gas
3 and the gate electrode 14 are dry-etched to form the insulating layer 1
Etching was stopped when 0.7 μm of 3 was dug.
Let

(Step 4) Next, as shown in FIG. 8D, a cathode electrode 12 having a thickness of 2 is formed by a sputtering method.
00 nm of Al was deposited. Then, by the CVD method,
As the electron emission film 15, a diamond-like carbon film was deposited on the bottom surface of the opening by about 50 nm. The reaction gas is C
A mixed gas of H ₄ , H ₂ and N ₂ was used.

(Step 5) Finally, as shown in FIG. 8E, the mask pattern 18 was completely removed, and the electron-emitting device of this example was completed.

The electron-emitting device manufactured as described above has the same structure as that shown in FIG. 5 with Va = 5 kV,
Electrons were emitted by driving at Vb = 20V, D1 = 1 mm and Vf = −40V.

Focusing electrode 1 having the same pixel size as that of this embodiment
6, the gate current and the electron beam diameter were reduced to about 54% and 83%, respectively, as compared with one having the cathode electrode 12 on one surface on the substrate 11 in the pixel.

Also in the electron-emitting device shown in this embodiment,
By applying a negative voltage to the focusing electrode 16, the effect of reducing the gate current and the electron beam diameter was obtained as in the first embodiment. The gate current and the electron beam diameter mentioned here are the same as those described in the first embodiment.

In this embodiment, the insulating layer 13 is composed of one layer, but it may be composed of a plurality of layers. In the case where the insulating layer is composed of a plurality of layers, the dielectric constant of the insulating layer of the insulating layer 13 on the substrate 11 side of the cathode electrode 12 is larger than that of the insulating layer on the gate electrode 14 side of the cathode electrode 12. It is preferably larger than the above.

[Embodiment 3] FIG. 9 shows an example of a schematic perspective view of an electron-emitting device manufactured according to Embodiment 3.

In this embodiment, an example is shown in which the distance between the cathode electrode and the focusing electrode is narrow at the pixel end. Here, only the characteristic part of the present embodiment will be described, and redundant description will be omitted.

The manufacturing process of the electron-emitting device of this embodiment is the same as the manufacturing process of the electron-emitting device of the first embodiment described above, but in the process 1 described in the first embodiment, the cathode close to both ends of the pixel is used. The distance W2 between the electrode and the focusing electrode is 0.4 μm
And the distance W2 between the other cathode electrode and the focusing electrode.
Was 1 μm.

The electron-emitting device manufactured as described above has the same structure as that shown in FIG. 5 with Va = 5 kV.
Driving with Vb = 20V, D1 = 1 mm, Vf = 10V,
Electrons were emitted.

A device capable of measuring a current was placed between the anode 19 and the cathode electrode 12, and the anode current at the time of electron emission was measured. The anode current mentioned here is a current flowing between the anode 19 and the cathode electrode 12 at the time of electron emission.

Electron emission manufactured in the same pixel size as in this embodiment, with the distance W2 between all the cathode electrodes and the focusing electrodes being 1 μm, and the electron beam diameter as a pixel being the same as that in this embodiment. The anode current was about 60% higher than that of the device. The electron-emitting device manufactured in this example has five rectangular openings in one pixel, and a comparison with this is one having three rectangular openings in one pixel.

This is because the distance between the cathode electrode and the focusing electrode is different between the left and right of the opening in the opening near the end of the pixel.
This is because the equipotential surface in the opening becomes asymmetric, and the electrons emitted from the electron emission film are emitted from the opening toward the central portion of the pixel. Further, in the present embodiment, only the distance W2 between the cathode electrode and the focusing electrode, which is close to the pixel end portion, is narrowed. However, the distance between the cathode electrode and the focusing electrode increases from the pixel center portion toward the pixel end portion. W2 may be narrowed continuously or discontinuously.

[Example 4] An image forming apparatus was produced using the electron-emitting devices of Examples 1 to 3.

The electron-emitting devices were arranged in a 100 × 100 MTX pattern. As for the wiring, as shown in FIG. 10, the x side was connected to the cathode electrode and the focusing electrode, and the y side was connected to the gate electrode. The elements were arranged at a pitch of 150 μm in the horizontal direction and 300 μm in the vertical direction. Phosphors were placed on the upper part of the device at a distance of 1 mm. A voltage of 5 kV was applied to the phosphor. A constant negative voltage of −10 V was applied to the focusing electrode. As a result,
A high-definition image forming apparatus capable of matrix driving was formed.

[0127]

As described above, in the electron-emitting device of the present invention, by applying a lower potential than that of the cathode electrode to the focusing electrode provided on the same plane as the cathode electrode or on the substrate side thereof, The equipotential surface formed between the gate electrode and the cathode electrode has a concave shape, which can reduce the risk that electrons emitted from the electron emitting material enter the insulating layer and charge up the insulating layer, and further reach the anode. The beam diameter of the electron at the time of doing can also be made small.

By changing the distance between the focusing electrode and the cathode electrode within the pixel, that is, by narrowing the distance between the focusing electrode and the cathode electrode closer to the end of the pixel. The shape of the equipotential surface formed between the gate electrode and the cathode electrode becomes asymmetric, and the emitted electrons are more concentrated in the central portion of the pixel, and the diameter of the electron beam as the pixel can be further reduced. . Therefore, the pixel area that can be used for electron emission can be made wider, and more emission current can be obtained. When the focusing electrode and the cathode electrode are on the same plane, the focusing electrode and the cathode electrode can be produced in the same process, so that the distance between the focusing electrode and the cathode electrode can be produced with good control.

In the electron-emitting device of the present invention, the gate electrode is used as a modulation electrode, and a high voltage can be applied to the anode. It collides with the body, and the phosphor provides sufficient brightness.

In the electron-emitting device of the present invention, the voltage applied between the gate electrode and the cathode electrode is reduced by reducing the thickness of the insulating layer or selecting a material having a small work function as the electron-emitting film. It can be driven at a low voltage.

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 schematic plan view showing a configuration of an electron-emitting device according to an embodiment.

FIG. 2 is a schematic perspective view showing an example of a configuration of an electron-emitting device according to an embodiment.

FIG. 3 is a schematic cross-sectional view showing an example of one opening of the electron-emitting device according to the embodiment.

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

FIG. 5 is a schematic cross-sectional view showing a configuration example when operating the electron-emitting device according to the embodiment.

FIG. 6 is a schematic plan view showing an electron-emitting device according to a second embodiment.

FIG. 7 is a schematic perspective view showing an electron-emitting device according to a second embodiment.

FIG. 8 is a diagram illustrating an example of a method for manufacturing the electron-emitting device according to the second embodiment.

FIG. 9 is a schematic perspective view showing an electron-emitting device according to a third embodiment.

FIG. 10 is a schematic configuration diagram showing an electron source having a simple matrix arrangement according to an embodiment.

FIG. 11 is a schematic configuration diagram showing an image forming apparatus using an electron source having a simple matrix arrangement according to an embodiment.

FIG. 12 is a diagram showing a fluorescent film used in the image forming apparatus according to the embodiment.

FIG. 13 is a schematic sectional view showing an example of a conventional FE type electron-emitting device.

FIG. 14 is a schematic cross-sectional view showing an example of a conventional FE type electron-emitting device in which a cathode electrode is dug.

FIG. 15 is a schematic cross-sectional view showing an example of a conventional FE type electron-emitting device having an electrode for focusing an electron beam in an opening.

[Explanation of symbols]

11 board 12 Cathode electrode 13 Insulation layer 13a insulating layer 13b insulating layer 14 Gate electrode 15 Electron emission film 16 Focusing electrode 17 equipotential surface 18 mask patterns 18a mask pattern 18b mask pattern 19 Anode 20 Orbits of emitted electrons 120 electron source substrate 121 Focused electrode wiring 122 Cathode electrode wiring 123 Gate electrode wiring 124 electron-emitting device 125 connections 131 Rear plate 132 Support frame 133 glass substrate 134 Fluorescent film 135 metal back 136 face plate 137 envelope 141 black conductive material 142 phosphor 301 substrate 302 cathode electrode 303 insulating layer 304 gate electrode 305 Electron emission film D1 Distance between gate electrode and anode W1 opening width W2 Distance between cathode electrode and focusing electrode Va Potential difference between cathode electrode and anode Vg Potential difference between gate electrode and cathode electrode Vf potential difference between focusing electrode and cathode electrode

Claims (13)

[Claims] 1. An electron having a first electrode, a second electrode insulated from the first electrode, and an electron-emitting material provided on the second electrode on a substrate. In an electron-emitting device forming an emission portion, a third electrode insulated from the first electrode and the second electrode is provided on the same plane as the second electrode or on the substrate side. And the voltage applied when driving the electron-emitting device is
An electron-emitting device characterized in that the first electrode, the second electrode, and the third electrode are larger in this order. 2. The electron emitting device according to claim 1, wherein the third electrode is insulated from the first electrode and the second electrode through an insulating layer. 3. The electron emitting device according to claim 1, wherein a plurality of the electron emitting portions are arranged. 4. The electron emitting device according to claim 3, wherein the distance between the second electrode and the third electrode is different depending on the electron emitting portion. 5. The distance between the second electrode and the third electrode becomes narrower toward the end in the direction in which the plurality of electron emitting portions are arranged among the plurality of electron emitting portions. The electron-emitting device according to claim 3 or 4, characterized in that. 6. The electron emitting device according to claim 1, wherein the electron emitting material is a thin film. 7. The electron emitting device according to claim 1, wherein the electron emitting material is substantially flat. 8. The electron emitting device according to claim 1, wherein the electron emitting material contains carbon. 9. An electron emitting device according to claim 1, wherein a plurality of electron emitting devices according to any one of claims 1 to 8 are arranged in parallel and are connected to each other. An electron source characterized by. 10. An electron-emitting device is driven by having at least one column of the electron-emitting device in which a plurality of the electron-emitting devices according to claim 1 are arranged. Therefore, a first wiring electrically connected to the first electrode and a second wiring electrically connected to the second electrode are arranged in a matrix, and the first wiring is connected to the third electrode. An electron source characterized in that there is a third wiring that is electrically connected. 11. The electron source according to claim 10, wherein the third wiring is arranged in parallel with the second wiring. 12. An electron source, comprising: the electron source according to claim 9; and an image forming member that forms an image with electrons emitted from the electron source. An image forming apparatus characterized by controlling the amount of electrons of each electron-emitting device. 13. The image forming apparatus according to claim 12, wherein the image forming member is a phosphor.