JPH10188855A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the dielectric withstand voltage, mechanical strength so as to enable application of a high acceleration voltage and visualization of clear image by supporting a substrate on which a plurality of electron radiation elements are formed and a transparent substrate in which a luminous material is formed by means of an aluminum nitride and a spacer covering its surface with the aluminum nitride. SOLUTION: A spacer 10 is fabricated on an aluminum nitride plate of 1.0mm in thickness by processing a hole of 0.25mm in diameter corresponding to an electron source by a carbonate gas laser. A face plate 7 is sufficiently aligned upwardly of a rear plate 2 and disposed via a side wall 3 and a spacer 10, and each bonding part is sealed with a flit glass. Thus, by forming the spacer 10 by the aluminum nitride, since a secondary electron emission rate is small, charge due to electron radiation is small, a creeping discharge is hardly generated, the dielectric withstand voltage is enhanced, and heat resistance and mechanical strength are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus using an electron-emitting device, an electron source substrate on which a large number of electron-emitting devices are formed and an anode substrate provided with a transparent electrode and a phosphor are arranged in parallel and evacuated to a vacuum. A flat type electron beam display panel is known.

[0003] Two types of electron-emitting devices are known: a thermionic type and a cold-cathode type. The cold-cathode-type electron-emitting devices include a field emission type (hereinafter abbreviated as FE type) and a surface conduction type. There are an electron-emitting device (hereinafter abbreviated as SCE) and a metal / insulating layer / metal-type electron-emitting device (hereinafter abbreviated as MIM type).

In an image forming apparatus such as an electron beam display panel, an apparatus using an FE type is disclosed, for example, in WPDyke & W.
W. Dolan, "Field emission", Advance in Electron Physi
cs, 8, 89 (1956) or CASpindt, "PHYSICAL Propert
ies of thin-film field emission cathodes with moly
bdenium cones ", J. Appl. Phys., 47, 5248 (1976) and I
Brodie, "Advanced technology: flat cold-cathode
CRTs ", Information Display, 1/89, 17 (1989) and the like are known.

As an example of the SCE type, MIElinso
n, Radio Eng. Electron Pys., 10, (1965). SC
The E type utilizes a phenomenon in which electron emission occurs when a current flows in a small area thin film formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using an SnO ₂ thin film by Elinson et al. And a device using an Au thin film [G. Dittmer: “Thin Solid Film”.
s ", 9,317 (1972)] , In 2 O 3 / SnO 2 by thin film [M.Hartwell and CGFonstad:". IEEE Trans ED Con
f. ", 519 (1975)], using a carbon thin film [Hisashi Araki
Others: Vacuum, Vol. 26, No. 1, p. 22 (1983)],
JP-A-7-45221 is known.

As an example of the MIM type, CAMead, "The tunn"
el-emission amplifier, J. Appl. Phys., 32, 646 (1961) and the like are known.

[0007] The flat type electron beam display panel can be made lighter and larger in size than a cathode ray tube (CRT) display device which is widely used at present, and uses a liquid crystal. As compared with other flat display panels such as a flat display panel, a plasma display, and an electroluminescent display, it is possible to provide higher brightness and higher quality images. FIGS. 13 and 14 are schematic configuration diagrams of a conventional flat electron beam display panel as an example of an image forming apparatus using an electron-emitting device. Here, FIG. 14 is a sectional view taken along the line AA ′ of FIG.

The structure of the conventional flat type electron beam display panel shown in FIGS. 13 and 14 will be described in detail.
Is a rear plate which is an electron source substrate, 102 is a face plate which is an anode substrate, and 103 is an outer frame, and these constitute a vacuum envelope. 104 is a glass substrate serving as a base of the rear plate, 105 is an electron-emitting device, and 106a and 106b are electrodes for applying a voltage to the electron-emitting device 105. 107a (scanning electrode) and 107b (signal electrode) are electrode wirings, which are connected to the electrodes 106a and 106b, respectively. Reference numeral 108 denotes a glass substrate which is a base of the face plate, 109 denotes a transparent electrode, and 110 denotes a phosphor. Reference numeral 111 denotes a spacer which holds the rear plate 101 and the face plate 102 at a predetermined interval and is arranged as a support member for atmospheric pressure.

In order to form an image on the electron beam display panel, a predetermined voltage is sequentially applied to the scanning wiring 107a and the signal wiring 107b arranged in a matrix, so that a predetermined electron emission position located at the intersection of the matrix is formed. The element 105 is selectively driven, and the emitted electrons are irradiated on the phosphor 110 to obtain a bright spot at a predetermined position. Note that the transparent electrode 109 is an element for accelerating the emitted electrons and obtaining a bright spot with higher luminance.
A high voltage is applied so as to be positive with respect to 105.
Here, the applied voltage depends on the performance of the phosphor,
It is a voltage of several hundred V to several tens kV. Therefore, the distance d between the rear plate 101 and the face plate 102 (more precisely, the distance between the wiring 107b and the transparent electrode 109) is set to 100% in order to prevent a vacuum dielectric breakdown (ie, discharge) from being caused by the applied voltage. Generally, it is set to be from μm to several mm.

As the display area of the display panel increases, the rear plate substrate 104 and the face plate substrate 108 need to be thickened in order to suppress the deformation of the substrate due to the difference between the vacuum inside the envelope and the atmospheric pressure outside. Have been. Increasing the thickness of the substrate not only increases the weight of the display panel, but also causes distortion when viewed from an oblique direction. Therefore, by arranging the spacer 111, the load on the strength of the substrates 104 and 108 can be reduced, and the weight, cost, and size of the screen can be reduced. Therefore, the advantages of the flat type electron beam display panel can be fully exhibited. You will be able to do it.

The material used for the spacer 111 is to have i) sufficient atmospheric pressure resistance (compression strength). ii) It has heat resistance enough to withstand the heating process in the manufacturing process and the high vacuum forming process, and has a matching thermal expansion coefficient with the display panel substrate, outer frame, and the like. iii) A high-resistance body (insulator) having a withstand voltage that can withstand high voltage application. iv) Outgassing rate should be low to maintain high vacuum. v) To be able to machine with high dimensional accuracy and to be excellent in mass productivity. Etc. are required, and a glass material is generally used.

On the other hand, "Advanced technology: flat cold-
cathode CRTs ”(17-19 of Information Display 1/89
Page) and US Patent No. 5,063,327.
Discloses a spacer using polyimide.
In this method, a photosensitive polyimide is applied to a substrate by a spin method, pre-baked, and then vacuum baked through a photolithography (mask exposure, development, washing) process, and finally applied to the cathode substrate surface. A polyimide spacer with a height of 100 μm is made. Further, U.S. Pat. No. 5,371,433 can be cited as an example utilizing photosensitive polyimide.

[0013]

However, when the above-mentioned spacer material is used, there are the following problems.

A general glass material is a material having relatively good mechanical strength, thermophysical properties, and emission gas characteristics.
In addition, the material is easy to use as a spacer because of good workability and mass productivity. However, with respect to the dielectric strength, creeping discharge is likely to occur particularly due to charging of the surface (which is considered to be due to secondary electron emission), so that a very high voltage cannot be applied, and a display with sufficient brightness is required. It is difficult to do.

On the other hand, when a spacer is formed from a polyimide resin by photolithography, the mechanical strength is inferior to that of a glass material, but the number of spacers to be arranged can be easily increased, so that atmospheric pressure resistance can be obtained. Although heat resistance and outgassing characteristics may be slightly inferior to those of glass materials, they can be used in glass envelopes without any problem by performing appropriate annealing treatment or the like. Regarding the electrical properties, the insulation resistance is good and the creepage withstand voltage is high. However, the workability has the following problems.

According to the photolithography process described above,
The height of the polyimide spacer formed in one process is at most several to several tens of μm, and it is necessary to repeat the process many times to obtain the desired height d. Therefore, the height of the spacer that can be actually used is at most about several hundred μm or less, and the voltage that can be applied to the face plate is limited. For this reason, high-acceleration electron phosphors (acceleration voltage several kV to several tens of kV) used in current CRTs are difficult to use, and low-acceleration electron phosphors with poor performance such as luminance and color purity are difficult to use. I had to use my body.

Further, since the spacer forming step is performed on the rear plate or the face plate, the residue of the polyimide remains on the rear plate or the face plate or damages the electron-emitting device during the step. There was also a concern. Further, if any trouble occurs during the process of forming the polyimide spacer, both the polyimide spacer and the rear plate or face plate must be discarded, resulting in an increase in cost and waste of resources.

[0018]

An image forming apparatus according to the present invention has a structure in which a substrate on which a plurality of electron-emitting devices are formed and a transparent substrate on which a luminescent material is formed are opposed to each other via a spacer. In the apparatus, the surface of the spacer is made of aluminum nitride.

Further, according to the image forming apparatus of the present invention, there is provided an image forming apparatus having a structure in which a substrate on which a plurality of electron-emitting devices are formed and a transparent substrate on which a luminescent material is formed are opposed to each other via a spacer. It is characterized by being made of aluminum or a base material coated with an aluminum nitride film.

That is, according to the present invention, a substrate (rear plate) and a phosphor substrate (face plate) in which a plurality of electron sources are formed by a spacer having a surface of aluminum nitride, particularly a spacer whose surface is coated with aluminum nitride or aluminum nitride. Are opposed to each other, and an image is displayed by accelerating the emitted electrons from the plurality of electron sources and irradiating the phosphor with the electrons.

In the present invention, the surface of the spacer may be made of aluminum nitride, and is not limited to the embodiments and examples described later.

As described above, two types of electron-emitting devices, thermionic type and cold-cathode type, are known. The cold-cathode type electron-emitting devices include a field emission type (hereinafter abbreviated as FE type), a surface conduction electron-emitting device (hereinafter abbreviated as SCE), and a metal / insulating layer / metal type (hereinafter MIM).
Abbreviated as type). The type of the electron-emitting device in the present invention is not particularly limited, but a cold cathode type is particularly preferably used.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the image forming apparatus of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an image forming apparatus centering on a spacer.
In the drawing, 1 is an electron source, 2 is a rear plate, 3 is a side wall, and 7 is a face plate. An airtight container (outside) for maintaining the inside of the display panel at a vacuum with the rear plate 2, the side wall 3, and the face plate 7 is provided. An enclosure 8) is formed. In assembling the airtight container, it is necessary to seal the joints of the members in order to maintain sufficient strength and airtightness. For example, frit glass is applied to the joints, and in a nitrogen atmosphere, 400 to 500 degrees Celsius. Seal by baking for 10 minutes or more.

Numeral 10 denotes a spacer made of aluminum nitride, which is set up on the X-direction wiring 9 in FIG. 1 so as not to block the electrons emitted from the electron source 1. The spacer 10 can be provided not only on the X-directional wiring 9 but also on other places on the Y-directional wiring. Further, in a configuration in which an intermediate electrode plate (grid electrode or the like) is provided between the face plate 7 and the rear plate 2 for the purpose of shaping an electron beam or preventing electrification of a substrate insulating portion, the spacer serves as an intermediate electrode plate or the like. It may penetrate or may be separately connected via an intermediate electrode plate or the like.

It is considered that the reason why aluminum nitride is excellent as a spacer is that the secondary electron emission rate is small, so that the charge due to electron irradiation is small and the surface discharge is unlikely to occur. Aluminum nitride has excellent heat resistance (melting point 22
00 ° C) and high mechanical strength.

The shape, arrangement and number of the spacers 10 are determined in consideration of the shape of the envelope 8 and the atmospheric pressure applied to the envelope. The shape of the spacer can be flat, cross, L
There are character shapes and the like, which are determined as appropriate. Alternatively, as shown in FIG. 3A, a shape in which holes corresponding to each electron source are formed in an aluminum nitride plate can be used. Further, the hole may include a plurality of electron sources (FIG. 3B). The number of spacers that can sufficiently support the atmospheric pressure is arranged. Even if the spacers are arranged in a straight line or in a lattice, they can be arranged in a staggered lattice. The effect of using the spacer 10 becomes remarkable as the size of the image forming apparatus increases.

The same effect can be obtained even if the spacer material is another insulating material and its surface is coated with an aluminum nitride film. The aluminum nitride film can be formed by a sputtering method, a reactive sputtering method, a sol-gel method, or the like. The aluminum nitride film may have a thickness sufficient to cover the base material almost completely, and may have a thickness of 10 nm or more.

For fixing the spacer, an adhesive having high heat resistance such as frit glass is used. Fig. 1
Alternatively, as shown in FIG. 2, frit glass 11 is used for the electrode and the face plate, and the electrode and the face plate are vertically set on the face plate and the rear plate.

FIG. 2 is a perspective view of a display panel used in this embodiment, in which a part of the panel is cut away to show the internal structure.

A substrate 13 is fixed to the rear plate 2, and N × M cold cathode type electron-emitting devices 1 are formed on the substrate 13 (N and M are two or more positive electrodes). This is an integer, and is appropriately set according to the target number of display pixels.
For example, in an image forming apparatus for displaying high-definition television, it is desirable to set N = 3000 and M = 1000 or more. In FIG. 2, the number of electron sources is shown in only four columns for simplification. ). N × M
The cold cathode type electron-emitting devices are composed of M X-directional wirings 9 and N
Simple matrix wiring is performed by the Y-directional wirings 12. The cold cathode type electron-emitting device 1, the X-directional wiring 9, the Y
The part constituted by the directional wiring 12 and the substrate 13 is called a multi-electron beam source. The manufacturing method and structure of the multi-electron beam source will be described later in detail.

In this embodiment, the substrate 13 of the multi-electron beam source is fixed to the rear plate 2 of the hermetic container. However, when the substrate 13 of the multi-electron beam source has a sufficient strength. The substrate 13 of the multi-electron beam source may be used as the rear plate of the hermetic container.

On the lower surface of the face plate 7, a fluorescent film 5 is formed. Since the present embodiment is a color image forming apparatus, phosphors of three primary colors of red, green and blue used in the field of CRT are separately applied to a portion of the fluorescent film 5. The phosphors of each color are separately applied in stripes as shown in FIG. 4A, for example, and black bodies 5b are provided between the stripes of the phosphors. The purpose of providing the black body 5b is to prevent the display color from being shifted even when the irradiation position of the electron beam is slightly shifted, to prevent reflection of external light, and to prevent a decrease in display contrast. It is. Although graphite was used as the main component for the black body 5b,
Other materials may be used as long as they are suitable for the above purpose. Further, the black body 5b may be made conductive.

The method of applying the phosphors of the three primary colors is not limited to the stripe arrangement shown in FIG. 4A, but may be, for example, a delta arrangement as shown in FIG. Other arrangements may be used.

When a monochrome display panel is formed, a monochromatic phosphor material may be used for the phosphor film 5, and a black body is not necessarily used.

On the surface of the fluorescent film 5 on the rear plate side, a metal back 6 known in the field of CRT is provided. The purpose of providing the metal back 6 is to improve the light utilization rate by mirror-reflecting a part of the light emitted from the fluorescent film 5,
Examples include protecting the fluorescent film 5 from collision with negative ions, acting as an electrode for applying an electron beam acceleration voltage, and acting as a conductive path for excited electrons of the fluorescent film 5. The metal back 6 was formed by forming the fluorescent film 5 on the face plate substrate 4, then smoothing the surface of the fluorescent film, and vacuum-depositing Al thereon. When a fluorescent material for low voltage is used for the fluorescent film 5, the metal back 6 may not be used.

Although not used in this embodiment,
A transparent electrode made of, for example, ITO may be provided between the face plate substrate 4 and the fluorescent film 5 for the purpose of applying an acceleration voltage or improving the conductivity of the fluorescent film.

Dx1 to Dxm, Dy1 to Dyn, and Hv are electric connection terminals having an airtight structure provided for electrically connecting the display panel to an electric circuit (not shown). Dx1 to Dxm are X-direction wirings 9 of the multi-electron beam source.
And Dy1 to Dyn are the Y-direction wirings 12 of the multi-electron beam source.
And Hv are electrically connected to the metal back 6 of the face plate.

In order to evacuate the inside of the airtight container including the face plate, the rear plate, and the frame, after assembling the airtight container, an exhaust pipe (not shown) and a vacuum pump are connected.
The inside of the airtight container is evacuated to a pressure of about 10 ⁻⁵ [Pa]. Thereafter, the exhaust pipe is sealed, but a getter film (not shown) is formed at a predetermined position in the airtight container immediately before or after the sealing in order to maintain the pressure in the airtight container. The getter film is, for example, a film formed by heating and depositing a getter material containing Ba as a main component by a heater or high-frequency heating, and the inside of the hermetic container is 10 ^{−3 to} 10 ⁻⁵ by the adsorption action of the getter film. Pa].

The basic configuration and manufacturing method of the display panel according to the embodiment of the present invention have been described above.

Next, a method of manufacturing the multi-electron beam source used for the display panel of the embodiment will be described. The multi-electron beam source used in the image forming apparatus of the present invention is not limited as long as it is an electron source in which cold-cathode electron-emitting devices are arranged in a simple matrix wiring. Therefore, for example, a cold cathode electron-emitting device such as a surface conduction electron-emitting device, an FE type, or an MIM type can be used.

However, in a situation where an inexpensive image forming apparatus having a large display screen is required, a surface conduction type electron-emitting device is particularly preferable among these cold cathode type electron-emitting devices. That is, in the FE type, since the relative position and shape of the emitter cone and the gate electrode greatly affect the electron emission characteristics, extremely high-precision manufacturing technology is required, but this achieves a large area and a reduction in manufacturing cost. Is a disadvantageous factor. In the case of the MIM type, it is necessary to make the thicknesses of the insulating layer and the upper electrode thin and uniform, which is also a disadvantageous factor in achieving a large area and a reduction in manufacturing cost. On the other hand, since the surface conduction electron-emitting device has a relatively simple manufacturing method, it is easy to increase the area and reduce the manufacturing cost. The present inventors have also found that among the surface conduction electron-emitting devices, those in which the electron-emitting portion or its peripheral portion is formed of a fine particle film have particularly excellent electron-emitting characteristics and can be easily manufactured. . Therefore, it can be said that it is most suitable for use in a multi-electron beam source of a high-luminance, large-screen image forming apparatus. Therefore,
In the display panel of the above embodiment, a surface conduction electron-emitting device in which the electron-emitting portion or its peripheral portion is formed of a fine particle film is used. Therefore, the basic configuration, manufacturing method, and characteristics of a suitable surface conduction electron-emitting device will be described first, and then the structure of a multi-electron beam source in which many devices are arranged in a simple matrix will be described. [Suitable device configuration and manufacturing method of surface conduction electron-emitting device] The surface-conduction electron-emitting device in which the electron-emitting portion or its peripheral portion is formed of a fine particle film has two typical types, a flat type and a vertical type. Is raised. (Flat-Type Surface-Conduction-Type Electron-Emitting Device) First, the device configuration and manufacturing method of a flat-type surface-conduction-type electron-emitting device will be described.

FIG. 5A is a plan view for explaining the structure of a plane type surface conduction electron-emitting device, and FIG. 5B is a sectional view of FIG. 5A. In the figure, 13 is a substrate, 14 and 1
5 is an element electrode, 16 is a conductive thin film, 17 is an electron-emitting portion formed by an energization forming process, and 18 is a thin film formed by an energization activation process.

As the substrate 13, for example, various glass substrates such as quartz glass and blue plate glass, various ceramics substrates such as alumina, or an insulating layer made of, for example, SiO ₂ is formed on the various substrates described above. A laminated substrate or the like can be used.

The device electrodes 14 and 15 provided on the substrate 13 in parallel with the substrate surface are formed of a conductive material. For example, Ni, Cr, A
Metals such as u, Mo, W, Pt, Ti, Cu, Pd, Ag and the like, alloys of these metals, metal oxides such as In ₂ O ₃ -SnO ₂ , and semiconductors such as polysilicon The material may be appropriately selected from the following. An electrode can be easily formed by using a combination of a film forming technique such as vacuum evaporation and a patterning technique such as photolithography and etching. However, other methods (eg, printing technique)
It can be formed by using the same.

The shapes of the device electrodes 14 and 15 are appropriately designed according to the application purpose of the electron-emitting device. Generally, the electrode spacing L is usually designed by selecting an appropriate value from the range of several tens of nm to several tens of μm. μm range. As for the thickness d of the device electrode, an appropriate numerical value is usually selected from the range of several tens nm to several μm.

Further, a fine particle film is used for the portion of the conductive thin film 16. The fine particle film described here refers to a film including a large number of fine particles as constituent elements (including an island-shaped aggregate). When the fine particle film is examined microscopically, usually, a structure in which the individual fine particles are arranged apart from each other, a structure in which the fine particles are adjacent to each other, or a structure in which the fine particles overlap each other is observed.

The particle size of the fine particles used for the fine particle film is several nm.
Although it is included in the range of 1/10 to several hundreds of nm, the preferable one is in the range of 1 to 20 nm. Further, the thickness of the fine particle film is appropriately set in consideration of various conditions described below. That is, conditions necessary for good electrical connection with the device electrode 14 or 15, conditions necessary for good energization forming described later, and electric resistance of the fine particle film itself to an appropriate value described later. Necessary conditions, etc. Specifically, it is set in the range of 1/10 to several hundred nm of several nm, but the range is preferably 1 nm to 50 nm.

Materials that can be used to form the fine particle film include, for example, Pd, Pt, Ru, Ag,
Au, Ti, In, Cu, Cr, Fe, Zn, Sn, T
a, W, Pb, and other metals, PdO, S
Oxides such as nO ₂ , In ₂ O ₃ , PbO, Sb ₂ O ₃ , etc .; HfB ₂ , ZrB ₂ , LaB ₆ , C
Borides such as eB ₆ , YB ₄ , GdB ₄ , etc., TiC, ZrC, HfC, TaC, SiC, WC,
And other carbides, TiN, ZrN, Hf
Nitrides such as N, etc., semiconductors such as Si, Ge, etc., carbon, and the like are listed, and are appropriately selected from these.

As described above, the conductive thin film 16 is formed of a fine particle film.
^It was set to be within the range of ³ to 10 ⁷ [Ohm / sq].

Since the conductive thin film 16 and the device electrodes 14 and 15 are desirably electrically connected well, they have a structure in which a part of each of them overlaps.
In the example of FIG. 5, the overlapping manner is as follows.
Although the device electrode and the conductive thin film are laminated in this order, the substrate, the conductive thin film and the device electrode may be laminated in this order from the bottom in some cases.

The electron emitting portion 17 is formed of a conductive thin film 16.
Is a crack-like portion formed in a part of the conductive thin film, and has a property of being higher in electrical resistance than the surrounding conductive thin film. The cracks are formed by performing a later-described energization forming process on the conductive thin film 16. Within a crack, a few nm
In some cases, fine particles having a particle diameter of 1/10 to several tens of nm are arranged. Since it is difficult to accurately and accurately show the actual position and shape of the electron-emitting portion, they are schematically shown in FIG.

The thin film 18 is a thin film made of carbon or a carbon compound, and covers the electron emitting portion 17 and its vicinity. After the energization forming process, the thin film 18
It is formed by performing an energization activation process described later.

The thin film 18 is made of any one of single-crystal graphite, polycrystalline graphite, and amorphous carbon, or a mixture thereof, and has a thickness of 50 nm or less.
More preferably, it is set to nm or less. The actual thin film 1
Since it is difficult to precisely illustrate the position and shape of the position 8 in FIG.
Is schematically shown.

Next, a description will be given of a method of manufacturing a suitable flat surface conduction electron-emitting device. 6 (a) to 6 (d)
Is a cross-sectional view for explaining a manufacturing process of the surface conduction electron-emitting device. In each of the constituent members, the same components as those in FIG. 5 are denoted by the same reference numerals. 1) First, device electrodes 14 and 15 are formed on a substrate 13 as shown in FIG. In the formation, the substrate 13 is sufficiently washed in advance with a detergent, pure water, and an organic solvent, and then the material of the element electrode is deposited (for example, vacuum deposition such as a vapor deposition method or a sputtering method). Technology can be used.) Thereafter, the deposited electrode material is patterned by using a photolithography and etching technique to form a pair of device electrodes 14 and 15. 2) Next, as shown in FIG.
To form In forming, first, the device electrode 1
An organic metal solution is applied to the substrate 13 on which the layers 4 and 15 are formed, dried, heated and baked to form a fine particle film, and then patterned into a predetermined shape by photolithography and etching. Here, the organometallic solution is a solution of an organometallic compound whose main element is a material of fine particles used for the conductive thin film. Specifically, in this embodiment, Pd was used as a main element. In the embodiment, the dipping method is used as the coating method, but other methods such as a spinner method and a spray method may be used.

As a method of forming a conductive thin film made of a fine particle film, other than the method of applying an organometallic solution used in this embodiment, for example, a vacuum deposition method, a sputtering method, or a chemical vapor deposition method In some cases, a deposition method or the like is used. 3) Next, as shown in FIG. 6C, an appropriate voltage is applied between the device electrodes 14 and 15 from the forming power supply 19 to perform the energization forming process, and
To form

The energization forming process is to energize the conductive thin film 16 made of a fine particle film and to appropriately break, deform, or alter a part of the conductive thin film 16 to change into a structure suitable for emitting electrons. This is the process that causes In a portion of the conductive thin film made of the fine particle film that has been changed to a structure suitable for emitting electrons (that is, the electron emitting portion 17), an appropriate crack is formed in the thin film. Note that the electrical resistance measured between the device electrodes 14 and 15 after the formation is significantly increased as compared with before the electron emission portion 17 is formed.

FIG. 7 shows an example of an appropriate voltage waveform applied from the forming power supply 19 in order to explain the energization method in more detail. When forming a conductive thin film made of a fine particle film, a pulsed voltage is preferable,
In the case of the present embodiment, as shown in FIG.
One triangular wave pulse was continuously applied at a pulse interval T2.
At that time, the peak value Vpf of the triangular wave pulse was sequentially increased. In addition, monitor pulses Pm for monitoring the state of formation of the electron-emitting portion 17 were inserted at appropriate intervals between the triangular-wave pulses, and the current flowing at that time was measured by the ammeter 20.

[0058] In the example embodiment, for example, in a vacuum atmosphere of about 10 ^-3 Pa, for example a pulse width T1 1
Milliseconds, the pulse interval T2 is 10 milliseconds, and the peak value Vpf
Was increased by 0.1 V for each pulse. Then, each time five triangular waves were applied, the monitor pulse Pm was inserted once. The monitor pulse voltage Vpm is set to 0. 1 so as not to adversely affect the forming process.
It was set to 1V. Then, when the electric resistance between the device electrodes 14 and 15 becomes 1 × 10 ⁶ ohms, that is, when the current measured by the ammeter 20 when the monitor pulse is applied is 1 × 10 ⁶ ohms.
When the current became 10 ⁻⁷ A or less, the energization related to the forming process was terminated.

The above method is a preferable method for the surface conduction electron-emitting device of this embodiment. For example, the material and film thickness of the fine particle film or the design of the surface conduction electron-emitting device such as the element electrode interval L If you change
It is desirable to appropriately change the energization conditions accordingly. 4) Next, as shown in FIG.
An appropriate voltage is applied between 1 and the device electrodes 14 and 15,
A current activation process is performed to improve electron emission characteristics.

The energization activation process is a process of energizing the electron-emitting portion 17 formed by the energization forming process under appropriate conditions to deposit carbon or a carbon compound in the vicinity thereof. In FIG. 6D,
A deposit made of carbon or a carbon compound is schematically shown as the member 18. Note that by performing the energization activation process, the emission current at the same applied voltage can be typically increased by 100 times or more as compared with before the energization activation process.

More specifically, by periodically applying a voltage pulse in a vacuum atmosphere within a range of 10 ^-1 to 10 ^-4 Pa, carbon or carbon originating from an organic compound existing in the vacuum atmosphere can be obtained. The carbon compound is deposited. The deposit 18
It is any one of single crystal graphite, polycrystal graphite and amorphous carbon, or a mixture thereof, and has a film thickness of 50 nm or less, more preferably 30 nm or less.

FIG. 8A shows an example of an appropriate voltage waveform applied from the activation power supply 21 in order to describe the energization method in more detail. In the present embodiment, the energization activation process is performed by applying a rectangular wave of a constant voltage periodically. Specifically, the voltage Vac of the rectangular wave is 14 V, the pulse width T3 is 1 millisecond, and the pulse width is 3 ms. The interval T4 was 10 milliseconds. The above-described energization conditions are preferable conditions for the surface conduction electron-emitting device of this embodiment, and when the design of the surface conduction electron-emitting device is changed, the conditions should be changed accordingly. desirable.

Reference numeral 22 shown in FIG. 6D denotes an anode electrode for capturing the emission current Ie emitted from the surface conduction electron-emitting device.
Is connected. When the activation process is performed after the substrate 13 is incorporated into the display panel, the phosphor screen of the display panel is used as the anode electrode 22.

While the voltage is applied from the activation power supply 21,
The emission current Ie is measured by the ammeter 24 to monitor the progress of the energization activation process, and the operation of the activation power supply 21 is controlled. FIG. 8B shows an example of the emission current Ie measured by the ammeter 24. When the pulse voltage is started to be applied from the activation power supply 21, the emission current Ie increases with the passage of time, but eventually saturates. And hardly increase. As described above, when the emission current Ie is substantially saturated, the application of the voltage from the activation power supply 21 is stopped, and the energization activation process ends.

The above-described energization conditions are preferable conditions for the surface conduction electron-emitting device of this embodiment.
When the design of the surface conduction electron-emitting device is changed, it is desirable to appropriately change the conditions accordingly.

As described above, the flat surface conduction electron-emitting device shown in FIG. 6E was manufactured. (Vertical Type Surface Conduction Electron Emitting Element) FIG. 9 shows another typical configuration of a surface conduction electron emitting element in which an electron emitting portion or its periphery is formed of a fine particle film, that is, a vertical surface conduction electron emitting device. Element. FIG. 9 is a schematic cross-sectional view for explaining the basic structure of the vertical type. In the figure, 25 is a substrate, 26 and 27 are device electrodes, 28 is a step forming member, and 29 is a conductive film using a fine particle film. Reference numeral 30 denotes an electron emitting portion formed by an energization forming process, and 31 denotes a thin film formed by an energization activation process.

The difference between the vertical type and the flat type described above is that one element electrode 26 is provided on the step forming member 28 and the conductive thin film 29 covers the side surface of the step forming member 28. On the point. Therefore, the element electrode interval L in the planar type shown in FIG. 5 is set as the step height Ls of the step forming member 28 in the vertical type. In addition, the substrate 2
5, the element electrodes 26 and 27, and the conductive thin film 29 using the fine particle film, the materials listed in the description of the flat type can be similarly used. For the step forming member 28, an electrically insulating material such as SiO ₂ is used. [Characteristics of Surface Conduction Electron-Emitting Device Used in Image Forming Apparatus] The element configuration and manufacturing method of the planar and vertical surface-conduction electron-emitting devices have been described above. The characteristics will be described.

FIG. 10 shows the elements used in the image forming apparatus.
Typical examples of (emission current Ie) versus (device applied voltage Vf) characteristics and (device current If) versus (device applied voltage Vf) characteristics are shown. Note that the emission current Ie is significantly smaller than the element current If, and it is difficult to show them on the same scale. In addition, these characteristics are changed by changing design parameters such as the size and shape of the element. Therefore, 2
The graphs in the book are shown in arbitrary units.

The device used in the image forming apparatus has an emission current I
e has three characteristics described below.

First, when a voltage higher than a certain voltage (hereinafter referred to as a threshold voltage Vth) is applied to the element, the emission current Ie sharply increases. On the other hand, when the voltage is lower than the threshold voltage Vth, the emission current Ie increases. Ie is hardly detected. That is, it is a non-linear element having a clear threshold voltage Vth with respect to the emission current Ie.

Secondly, since the emission current Ie changes depending on the voltage Vf applied to the element, the emission current Ie varies with the voltage Vf.
The magnitude of e can be controlled.

Third, since the response speed of the current Ie emitted from the device is fast with respect to the voltage Vf applied to the device, the amount of charge of the electrons emitted from the device depends on the length of time for applying the voltage Vf. Can control.

With the above characteristics, the surface conduction electron-emitting device can be suitably used in an image forming apparatus. For example, in an image forming apparatus in which a large number of elements are provided corresponding to pixels of a display screen, if the first characteristic is used, it is possible to sequentially scan the display screen to perform display. That is, a voltage equal to or higher than the threshold voltage Vth is appropriately applied to the element being driven, and a voltage lower than the threshold voltage Vth is applied to the element in a non-selected state. By sequentially switching the elements to be driven, the display screen can be sequentially scanned and displayed.

Further, by using the second characteristic or the third characteristic, the light emission luminance can be controlled, so that a gradation display can be performed. (Structure of a multi-electron beam source in which a large number of devices are arranged in a simple matrix) Next, a structure of a multi-electron beam source in which the above-described surface conduction electron-emitting devices are arranged on a substrate and arranged in a simple matrix will be described.

FIG. 11 is a plan view of the multi-electron beam source used for the display panel of FIG. On the substrate, surface conduction electron-emitting devices similar to those shown in FIG. 5 are arranged.
Wires are arranged in a simple matrix by the direction wiring electrodes 12. An insulating layer (not shown) is formed between the X-directional wiring electrodes 9 and the Y-directional wiring electrodes 12 at the intersections thereof to maintain electrical insulation. FIG. 12 shows a cross section along the line AA ′ in FIG.

The multi-electron source having such a structure is as follows.
After forming the X-direction wiring electrode 9, the Y-direction wiring electrode 12, the interelectrode insulating layer (not shown), the device electrode of the surface conduction electron-emitting device and the conductive thin film on the substrate in advance, the X-direction wiring electrode 9 and the It was manufactured by performing a power supply energization forming process and an energization activation process on each element via the Y-direction wiring electrode 12.

[0077]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. (Example 1) In this example, first, a plurality of unformed surface conduction electron sources 1 were formed on a rear plate 2.
A cleaned blue plate glass is used as the rear plate 2, and 240 surface conduction electron-emitting devices shown in FIG.
480 pieces were formed in a matrix. The device electrodes 14 and 15
The X direction wiring 9 and the Y direction wiring 12 are Ag wirings formed by a screen printing method. The conductive thin film 16 is a 10 nm thick PdO layer obtained by firing a Pd amine complex solution.
It is a fine particle film.

As shown in FIG. 4A, the fluorescent film 5 serving as an image forming member adopts a stripe shape in which each color phosphor 5a extends in the Y direction, and the black body 5b is only between the color phosphors 5a. However, a shape in which pixels are provided in the X direction to separate the pixels in the Y direction and a portion for installing the spacer 10 is added. First, a black body (conductor) 5b was formed, and the phosphor 5a of each color was applied to a gap between the black body 5b and the phosphor film 5 was formed. As a material of the black stripe (black body 5b), a material mainly containing graphite, which is generally used, was used. A slurry method was used to apply the phosphor 5a to the glass substrate 4.

The metal back 6 provided on the inner surface side (electron source side) of the fluorescent film 5 is subjected to a smoothing process (usually called filming) of the inner surface of the fluorescent film 5 after the fluorescent film 5 is formed. Then, Al was formed by vacuum evaporation. The face plate 7 may be provided with a transparent electrode on the outer surface side (between the glass substrate and the fluorescent film) of the fluorescent film 5 in order to further enhance the conductivity of the fluorescent film 5, but in this experimental example, only a metal back is provided. Was omitted because sufficient conductivity was obtained.

The rear plate 2 in which a plurality of electrons have been formed is:
The face plate 7 is disposed 2 mm above via the support frame 3 and the spacer 10, and the joint between the rear plate 2, the face plate 7, the support frame 3 and the spacer 10 is fired with frit glass at 430 ° C. for 10 minutes or more in nitrogen. It was sealed.

The spacer is a 1.0 mm thick aluminum nitride plate having a hole of 0.25 mmφ corresponding to the electron source.
The holes were formed by processing a sintered substrate of aluminum nitride with a carbon dioxide gas laser. At the time of sealing, the rear plate 2, the face plate 7, and the spacer 10 were sufficiently aligned because the phosphors of each color had to correspond to the electron-emitting devices.

The atmosphere in the envelope 8 completed as described above is exhausted by a vacuum pump through an exhaust pipe (not shown).
After reaching a sufficiently low pressure, terminals Dx1 to Dxm and Dy1
A voltage was applied between the device electrodes 14 and 15 of the electron-emitting device 1 through Do Doyn, and the conductive thin film 16 was subjected to an energization process (forming process) to form an electron-emitting portion 17. The forming process was performed by applying a voltage having a waveform shown in FIG.

Thereafter, the external terminals Dx to Dxm and Dy1 to Dyn
By the time, a voltage pulse is applied periodically to perform an activation process for depositing carbon or a carbon compound existing in a vacuum atmosphere. The energization was activated by applying a waveform as shown in FIG.

Next, at a pressure of about 10 ^-4 Pa, an exhaust pipe (not shown) was welded by heating with a gas burner, and the envelope 8 was sealed.

Finally, in order to maintain the pressure after sealing,
Getter processing was performed.

In the image forming apparatus completed as described above, the external terminals Dx1 to Dxm, Dy
Electrons are emitted by applying a scanning signal and a modulation signal through signal generation means (not shown) through 1 to Dyn, respectively, and the emitted electron beam is accelerated by applying a high voltage to the metal back 6 through a high voltage terminal Hv. An image was displayed by causing electrons to collide with the phosphor film 5 to excite and emit light from the phosphor. The voltage applied between the device electrodes 14 and 15
Vf was set to 14V.

In this embodiment, the acceleration voltage Va can be applied to 8 kV without discharging, and a practically sufficient luminance (100 ftL) as an image forming apparatus was obtained.

Example 2 An aluminum nitride film having a thickness of 0.1 μm was sputter-deposited on both sides of a washed 0.25 mm-thick soda-lime glass substrate using AlN as a target and then 1.3 m wide.
m, and cut to a length of 20 mm, which was used as a spacer. The film was formed in a mixed gas of 1 Pa of argon gas and 0.5 Pa of nitrogen gas under the condition of high frequency power of 500 W.

As shown in FIG. 1, the spacer manufactured as described above was fixed to the face plate and the X-direction wiring by frit glass. Spacers were arranged in a zigzag pattern every 20 wires in the X direction.

The electron source, the phosphor, and the like were the same as in Example 1, and the other steps of the spacer were the same as in Example 1 to produce an image forming apparatus.

In this embodiment, Va can be applied to 7 kV without discharging, and sufficient luminance was obtained.

In the above embodiment, the surface conduction electron-emitting device was used as the electron source. However, the present invention is not limited to this, and the same effect can be obtained by using a cold cathode electron source such as a field emission electron-emitting device. . (Comparative Example) An image forming apparatus similar to that of Example 2 was manufactured by using a spacer of soda lime glass without forming an aluminum nitride film instead of the spacer of Example 2, but discharge was performed at Va = 3.5 kV. However, no more voltage could be applied.

[0093]

As described above, the substrate on which a plurality of electron-emitting devices are formed and the transparent substrate on which a luminescent material is formed are
By supporting with a spacer whose surface is made of aluminum nitride, in particular, a spacer whose surface is coated with aluminum nitride or aluminum nitride, a high acceleration voltage can be applied, and a clearer image display can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view centering on a spacer of an image forming apparatus of the present invention.

FIG. 2 is a perspective view of the image forming apparatus according to the embodiment of the present invention, in which a part of a display panel is cut away.

FIG. 3 is a schematic view of a spacer shape applicable to the image forming apparatus of the present invention.

FIG. 4 is a plan view illustrating a phosphor array of a face plate of the display panel.

FIG. 5 is a plan view and a cross-sectional view of a substrate of the multi-electron beam source.

FIG. 6 is a process chart of forming a planar surface conduction electron-emitting device.

FIG. 7 is a waveform diagram of a forming application pulse of an electron beam source.

FIG. 8 is a waveform diagram of a pulse for applying an energization activation step.

FIG. 9 is a sectional view of a vertical surface conduction electron-emitting device.

FIG. 10 is a diagram showing the relationship between the device voltage, the device current, and the emission current of the surface conduction electron-emitting device.

FIG. 11 is a simple matrix wiring diagram.

FIG. 12 is a sectional view of a planar surface conduction electron-emitting device.

FIG. 13 is a schematic configuration diagram of a conventional flat electron beam display panel.

FIG. 14 is a sectional view taken along line AA ′ of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electron source (electron emitting element) 2 rear plate 3 side wall 4 glass substrate 5 fluorescent film 6 metal back 7 face plate 8 envelope 9 X-direction wiring 10 spacer 11 good conductive electrode 12 Y-direction wiring 13 substrate

Claims (4)

[Claims] 1. An image forming apparatus having a structure in which a substrate on which a plurality of electron-emitting devices are formed and a transparent substrate on which a light emitting material is formed are opposed to each other via a spacer, wherein the surface of the spacer is made of aluminum nitride. Characteristic image forming apparatus. 2. An image forming apparatus having a structure in which a substrate on which a plurality of electron-emitting devices are formed and a transparent substrate on which a luminescent material is formed are opposed to each other via a spacer, wherein the spacer is made of aluminum nitride. Image forming apparatus. 3. An image forming apparatus having a structure in which a substrate on which a plurality of electron-emitting devices are formed and a transparent substrate on which a light-emitting material is formed are opposed to each other via a spacer. An image forming apparatus characterized in that the spacer is a formed spacer. 4. The image forming apparatus according to claim 1, wherein said electron-emitting device is a surface conduction electron-emitting device.