JP3099003B2 - Image forming device - Google Patents

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, and more particularly, to an image forming apparatus having a structure in which a substrate on which a plurality of electron-emitting devices are formed and a front plate on which a luminescent material is formed face each other via a spacer. It is about.

[0002]

2. Description of the Related Art Flat-panel displays having a small depth are attracting attention as a replacement for cathode-ray tube displays because they are space-saving and lightweight. At present, there are flat type displays using a liquid crystal type, a plasma emission type, and a multi-electron source. Plasma emission type and multi-electron source displays have a large viewing angle and the image quality is comparable to that of a cathode ray tube, so that high quality images can be displayed.

[0003] Such an image forming apparatus includes a back plate provided with a large number of minute electron sources on a substrate, a front plate made of glass on which a phosphor is formed, and a vacuum container together with the back plate and the front plate. A supporting frame to be formed and a spacer for maintaining a space between the back plate and the front plate are provided. As the electron source, cold-cathode electron-emitting devices such as a field-emission electron device or a surface-conduction electron-emitting device that emits electrons from a conical or needle-like tip capable of achieving high density have been developed. .

[0004] As the display area of the display increases, it is necessary to increase the thickness of the substrate and the front glass plate in order to suppress the deformation of the substrate due to the difference between the internal vacuum and the external atmospheric pressure. This not only increases the weight of the display, but also causes distortion of the image when viewed at an angle. In order to support the atmospheric pressure using a relatively thin glass plate, a structural support called a spacer or a rib is used between the substrate and the front glass. The distance between the substrate on which the electron source is formed and the front glass on which the phosphor is formed is usually maintained at a sub-millimeter to several millimeters, and the inside is maintained at a high vacuum as described above. A high voltage of several hundred volts or more is applied between the electron source and the phosphor in order to accelerate electrons emitted from the electron source. That is, since a strong electric field exceeding 1 kV / mm in electric field strength is applied between the phosphor and the electron source, there is a concern about discharge at the spacer portion.

In addition, the spacer is charged by a part of the electrons emitted from the nearby electron source or by the positive ions ionized by the emitted electrons adhering to the spacer. Electrons emitted from the electron source due to the charging of the spacer are bent in their trajectories, reach a position different from the normal position on the phosphor, and when the display image is viewed through the front glass, the image near the spacer is It is distorted.

[0006] In order to solve this problem, it has been proposed to remove charging by causing a small current to flow through the spacer (Japanese Patent Application Laid-Open Nos. 57-118355 and 61-124031). In this technology, a high-resistance thin film is formed on the surface of an insulating spacer,
A minute electric current is made to flow on the spacer surface. The antistatic film used here is tin oxide or a mixed crystal thin film of tin oxide and indium oxide or a metal film.

[0007]

The semiconductor type thin film such as tin oxide used in the above conventional example is so sensitive to gas such as oxygen as to be applied to a gas sensor, and its resistance value is liable to change in an atmosphere. In addition, since these materials and metal films have low specific resistance, they need to be formed in an island shape or extremely thinned in order to increase the resistance. That is, the conventional high-resistance film has drawbacks in that the reproducibility of film formation is difficult, and the resistance value is easily changed in a heat process such as frit sealing or baking in a display manufacturing process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device using a spacer provided with an antistatic film having high stability and good reproducibility, overcoming the above-mentioned disadvantages of the conventional spacer.

[0009]

SUMMARY OF THE INVENTION The present invention provides an image 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.
In the forming apparatus , the spacer includes an insulating base material,
A first layer made of an oxide of a transition metal covering the surface thereof, and niobium oxide and oxide oxide provided outside the first layer.
Funiumu, tungsten oxide or Bei example and a second layer consisting of a mixture thereof, the film thickness of the second layer 5nm~3
0 nm . In addition, the present invention
The substrate on which the electron-emitting device was formed and the luminescent material were formed
It has a structure in which a transparent substrate is opposed via a spacer.
In the image forming apparatus, the spacer has an insulating property.
Consists of a substrate and a transition metal oxide that covers the surface
A first layer, and niobium oxide provided outside the first layer;
Hafnium oxide, tungsten oxide, or a mixture of these
A second layer made of a compound, wherein the insulating base material contains Na.
The insulating substrate and the first layer
Silicon oxide film and zirconium oxide
Blocks made of aluminum film or aluminum oxide film
It is characterized in that a layer is provided .

In an image forming apparatus, an antistatic film removes charges accumulated on the surface of an insulating material by coating the surface of the insulating material with a conductive film.
It is necessary that the surface resistance (sheet resistance Rs) of the antistatic film is 10 ¹² Ω or less. Furthermore, in order to obtain a sufficient antistatic effect, a lower resistance value is sufficient and 10 ¹¹ Ω.
It is preferable that the value be as follows, and if the resistance is lower, the static elimination effect is improved.

When the antistatic film is applied to the spacer of the display, the surface resistance Rs of the spacer is set to a desirable range from the viewpoint of the antistatic and power consumption. The lower limit of the sheet resistance is limited by the power consumption of the spacer. The lower the resistance, the quicker the charge accumulated in the spacer can be removed, but the more power is consumed by the spacer. The antistatic film used for the spacer is preferably a semiconductive material rather than a metal film having a low specific resistance. The reason is that when a material having a small specific resistance is used, the thickness of the antistatic film must be extremely thin in order to make the surface resistance Rs a desired value. Although it depends on the surface energy of the thin film material, the adhesion to the substrate, and the substrate temperature, a thin film of 10 nm or less generally has an island shape, has an unstable resistance and has poor film reproducibility.

Therefore, semiconductive materials having a specific resistance value larger than that of a metal conductor and smaller than that of an insulator are preferable, but these materials often have a negative temperature coefficient of resistance. If the temperature coefficient of resistance is negative, the resistance value decreases due to the temperature rise due to the power consumed on the surface of the spacer, and furthermore, heat is generated and the temperature continues to rise, causing an excessive current to flow, so-called thermal runaway. However, thermal runaway does not occur in a situation where the calorific value, that is, power consumption and heat radiation are balanced. If the absolute value of the temperature coefficient of resistance TCR of the antistatic film material is small, it is difficult to cause thermal runaway.

The power consumption per 1 cm ² of the spacer is about 0.1 under the condition that an antistatic film having a TCR of -1% is used.
Experiments have shown that when W exceeds W, the current flowing through the spacer continues to increase, resulting in a thermal runaway state.
This depends, of course, on the shape of the spacer, the voltage Va applied between the spacers, and the temperature coefficient of resistance of the antistatic film. From the above conditions, the value of Rs whose power consumption does not exceed 0.1 W / cm ² is 10%. × Va ² Ω or more. That is, the sheet resistance Rs of the antistatic film formed on the spacer needs to be set in the range of 10 × Va ² Ω to 10 ¹¹ Ω.

As described above, the thickness t of the antistatic film formed on the insulating spacer is desirably 10 nm or more. On the other hand, when the film thickness t is 1 μm or more, the film stress increases, and the risk of peeling or cracking increases. Therefore, it is desirable that the film thickness be 10 nm to 1 μm, and more preferably 20 to 500 nm.

The specific resistance ρ is the product of the sheet resistance Rs and the film thickness t. From the preferable range of Rs and t described above, the specific resistance ρ of the antistatic film is 10 ⁻⁵ × Va ² to 10 ⁷ Ωcm. Desirably. Further, in order to realize more preferable ranges of the sheet resistance and the film thickness, ρ is (2 × 10 ⁻⁵ ) Va.
^It is preferable to set it to ^{2 to} 5 × 10 ⁶ Ωcm.

The acceleration voltage Va of electrons in the display
Is 100 V or more, and 1 k
V voltage is required. Under the condition of Va = 1 kV, the specific resistance of the antistatic film is preferably in the range of 10 to 10 ⁷ Ωcm.

As a result of intensive studies on materials for realizing the above-described characteristics of the antistatic film, the first layer was formed of a semiconductive oxide film of a transition metal in order to quickly release the charged electric charges.
The second layer, the secondary electron emission coefficient is less likely to charge small, transition
It has been found that a two-layered antistatic film composed of a metal oxide film is extremely excellent.

In particular, the first layer is made of iron oxide, cobalt oxide,
Copper oxide, ruthenium oxide, or a mixture of these with other transition metals is preferred, but from the viewpoint of the temperature coefficient of resistance that is an indicator of thermal runaway, more preferably, iron oxide, cobalt oxide, copper oxide, ruthenium oxide, and Chromium oxide, zirconium oxide, niobium oxide, hafnium oxide,
A mixture of tantalum oxide, tungsten oxide, ruthenium oxide and yttrium oxide is preferred.

The second layer is composed of niobium oxide, hafnium oxide,
Preference is given to tungsten oxide and mixtures thereof. Although the second layer is an insulator, the second layer may be a semiconductor whose specific resistance combined with the first layer achieves the preferable range described above.

The spacer coated with a metal oxide is also described in Japanese Patent Application Laid-Open No. 8-508846, but the first layer is formed of a transition metal oxide in order to quickly release the charged charges. There is no description of an antistatic film in which the second layer is a transition metal film having a small secondary electron emission coefficient and being difficult to be charged.

In the present invention, the first antistatic film,
The metal oxide thin film of the layer and the second layer can be formed by a vacuum evaporation method, a sputtering method, or a CVD method, but the insulating property is obtained by a simple thin film forming means such as a dipping method, a spinner method, a spray method, and a potting method. It can be formed on a member. For example, metal oxide fine particles, preferably 200
A dispersion of fine particles having a particle size of μm or less, or a solution of a sol such as a metal alkoxide, a metal salt of an organic acid, and a derivative thereof is first mixed and coated according to the application, dried, and then baked at 400 to 1000 ° C. Thus, the desired antistatic film is obtained. However, considering the stability of the solution, it is preferable not to use a mixture of the metal alkoxide and the organic acid metal salt.

The metal oxide thin films of the first and second layers, which are the antistatic films of the present invention, have a stable antistatic function without oxidizing and reducing reactions during the assembly process of the image display device. realizable.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A display device to which the antistatic film of the present invention is applied will be specifically described.

FIG. 1 is a cross-sectional view schematically showing a portion around a spacer 10 of the image forming apparatus of the present invention. In FIG. 1, reference numeral 1 denotes a number of minute electron sources, 2 denotes a rear plate which is a substrate, and 3 denotes a side wall. 4 is a glass substrate on which the phosphor 5 is formed, 6 is a metal back,
Thus, the face plate 7 is formed. The rear plate 2, the side walls 3, and the face plate 7 form an airtight container (enclosure 8) for maintaining the inside of the display panel at a vacuum.

The spacer 10 has an antistatic film 10c of the present invention formed on the surface of an insulating substrate 10a. The spacer 10 is provided to prevent the vacuum envelope 8 from being damaged or deformed by receiving the atmospheric pressure by evacuating the interior of the envelope 8. The material, shape, arrangement, and number of the spacers 10 are determined in consideration of the shape of the envelope 8, the coefficient of thermal expansion, the atmospheric pressure, heat, and the like that the envelope receives. Examples of the shape of the spacer include a flat plate type, a cross shape, and an L-shape. The effect of using the spacer 10 becomes significant as the size of the image forming apparatus increases.

The insulating base material 10a is provided with a face plate 7
Further, since it is necessary to support the atmospheric pressure applied to the rear plate 2, a material having high mechanical strength and high heat resistance, such as glass and ceramics, is suitable. When glass is used as the material of the face plate 7 and the rear plate 2, the insulating base material 10 a of the spacer 10 is made of the same or similar material as possible in order to suppress thermal stress during the display device manufacturing process. It is desirable that the material has a coefficient of thermal expansion.

When glass containing alkali ions such as soda glass is used for the insulating base material 10a, for example, the conductivity of the antistatic film 10c may be changed by Na ions. By forming a Na block layer 10b of Si nitride, Al oxide, Zr oxide or the like between the insulating base material 10a and the antistatic film 10c, it is possible to suppress the penetration of alkali ions such as Na into the antistatic film 10c. .

The spacer 10 is electrically connected to the metal back 6 and the X-directional wiring 9, so that substantially the acceleration voltage Va is applied to both ends of the spacer 10. In this example, the spacer 10 is connected to the X-directional wiring 9, but may be connected to an electrode formed separately. Further, in a configuration in which an intermediate electrode plate (grid electrode or the like) is formed between the face plate 7 and the rear plate 2 to form an electron beam or to prevent electrification of a substrate insulating portion, the spacer 10 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.

When electrodes 11 of good conductivity such as Al and Au are formed at both ends of the spacer 10, the antistatic film 10c is formed.
This is effective in improving the electrical connection between the electrode 11 on the face plate 7 and the electrode 11 on the rear plate 2.

Next, a display device using the above-described spacer will be described.

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

In the drawing, reference numeral 2 denotes a rear plate, 3 denotes a side wall, and 7 denotes a face plate, and forms an airtight container (enclosure 8) for maintaining the inside of the display panel at a vacuum by 2, 3, and 7. ing. When assembling the envelope 8, 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 the joints are exposed to air or a nitrogen atmosphere. So, 400 ~
Sealing is performed by baking at 500 ° C. for 10 minutes or more. A method of evacuating the inside of the envelope 8 to a vacuum will be described later.

A substrate 13 is fixed to the rear plate 2, and N × M cold cathode devices 1 are formed on the substrate. N and M are positive integers of 2 or more, and are appropriately set according to the target number of display pixels. For example, in a display device for displaying high-definition television, it is desirable to set N = 3000 and M = 1000 or more.

The N × M cold cathode devices are arranged in a simple matrix by M X-directional wirings 9 and N Y-directional wirings 12. The portion constituted by the elements 1, 9, 12, and 13 is called a multi-electron beam source. In addition, regarding the manufacturing method and structure of the multi-electron beam source,
I will elaborate later.

In this embodiment, the substrate 13 of the multi-electron beam source is fixed to the rear plate 2 of the envelope 8. 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 2 of the envelope 8.

On the lower surface of the face plate 7, a fluorescent film 5 is formed. Since this example is a color display device, phosphors 5a 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. As shown in FIG. 3A, the phosphors of each color are separately applied in stripes, and black conductors 5b are provided between the stripes of the phosphors. The purpose of providing the black conductor 5b is to prevent the display color from being shifted even if the electron beam irradiation position is slightly shifted;
This includes preventing reflection of external light to prevent a reduction in display contrast, and preventing charge-up of a fluorescent film by an electron beam. For the black conductor 5b, graphite can be used as a main component, but any other material may be used as long as it is suitable for the above purpose.

The method of applying the three primary color phosphors 5a is not limited to the stripe arrangement shown in FIG. 3A, but may be, for example, a delta arrangement as shown in FIG. , Or any other array.

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

On the surface of the fluorescent film 5 on the rear plate 2 side, a metal back 6 known in the field of CRT is provided. The purpose of providing the metal back 6 is to improve a light utilization rate by mirror-reflecting a part of the light emitted from the fluorescent film 5, to protect the fluorescent film 5 from the collision of negative ions, and to apply an electron beam accelerating voltage. Acting as an electrode for
And making the fluorescent film 5 act as a conductive path for the excited electrons. 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 5, and vacuum-depositing Al thereon. When a fluorescent material for low voltage is used for the fluorescent film 5, the metal back 6 is not used.

Although not used in this embodiment, a transparent electrode made of, for example, ITO is provided between the face plate 7 and the fluorescent film 5 for the purpose of applying an acceleration voltage and improving the conductivity of the fluorescent film 5. You may.

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 electrically connected to the X-directional wiring 9 of the multi-electron beam source, Dy1 to Dyn are electrically connected to the Y-directional wiring 12 of the multi-electron beam source, and Hv is electrically connected to the metal back 6 of the face plate 7.

In order to evacuate the inside of the airtight container (envelope 8), after assembling the envelope 8, an exhaust pipe (not shown) and a vacuum pump are connected, and the inside of the envelope 8 is 10 ^{−. 7} [torr]
Evacuate to a degree of vacuum. Thereafter, the exhaust pipe is sealed, but a getter film (not shown) is formed at a predetermined position in the envelope 8 immediately before or after the sealing in order to maintain the degree of vacuum in the envelope 8. I do. The getter film is, for example, Ba
Is a film formed by heating and evaporating a getter material mainly composed of .gamma. By a heater or high-frequency heating, and the inside of the envelope 8 is 1 × 10 ⁻⁵ or 1 × 10 ⁻⁷ [torr] due to the adsorbing action of the getter film. ] Is maintained.

Next, a method for manufacturing a multi-electron beam source used for the above display panel will be described. The material, shape, and manufacturing method of the cold cathode device are not limited as long as the multi-electron beam source used for the image display device of the present invention is an electron source in which cold cathode devices are arranged in a simple matrix. Therefore, for example, a surface conduction type emission element, an FE type, or M
A cold cathode device such as an IM type can be used.

However, in a situation where a display device having a large display screen and an inexpensive display device is required, among these cold cathode devices, a surface conduction type emission device is particularly preferable. 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. In addition, the inventors have 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 display device.

Therefore, in the above display panel, a surface conduction electron-emitting device having an electron-emitting portion or its peripheral portion formed of a fine particle film was 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 Emission Device) Representative configurations of a surface conduction electron-emitting device in which an electron-emitting portion or its peripheral portion is formed of a fine particle film include a flat type and a vertical type. Kinds are given.

(Flat-type surface conduction electron-emitting device)
An element configuration and a manufacturing method of the planar type surface conduction electron-emitting device will be described.

FIGS. 4A and 4B are views for explaining the structure of a planar surface conduction electron-emitting device, wherein FIG. 4A is a plan view and FIG. 4B is a cross-sectional view. In the figure, 13 is a substrate, 14 and 15 are device electrodes, 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 stacked 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 Any of the materials may be appropriately selected and used. An electrode can be easily formed by using a combination of a film forming technique such as vacuum deposition and a patterning technique such as photolithography and etching. However, the electrode can be formed by other methods (for example, printing technique). I can't wait.

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 interval L is usually designed by selecting an appropriate numerical value from the range of several tens of nm to several tens of 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 spaced 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 using the fine particle film is several hundred p
Although it is included in the range of m to several hundreds of nm, particularly preferred is the one 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 to the device electrode 14 or 15, conditions necessary for good energization forming described below,
Conditions necessary for setting the electric resistance of the fine particle film itself to an appropriate value described later, and the like. Specifically, it is set in the range of several hundreds of pm to several hundreds of nm, and particularly preferably, it is in the range of 1 to 50 nm.

Also, it can be used to form a fine particle film.
As the material, for example, Pd, Pt, Ru, Ag, A
u, Ti, In, Cu, Cr, Fe, Zn, Sn, T
a, W, Pb and other metals, PdO, Sn
O_Two, In_TwoO_Three, PbO, Sb_TwoO_ThreeAnd others
Oxide or HfB_Two, ZrB_Two, LaB₆, CeB
₆, YB_Four, GdB_FourBorides such as T
iC, ZrC, HfC, TaC, SiC, WC, etc.
Carbide, TiN, ZrH, HfN, etc.
Nitride and semi-finished materials such as Si and Ge
Conductors, carbon, etc.
It is appropriately selected.

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 [Ω / sq].

Since it is desirable that the conductive thin film 16 and the device electrodes 14 and 15 are electrically connected well, a structure is adopted in which a part of each of them overlaps.
In the example shown in FIG.
3, the device electrodes 14, 15 and the conductive thin film 16 were laminated in this order.
6, the device electrodes 14 and 15 may be stacked in this order.

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 16 and has a higher electrical property than the surrounding conductive thin film 16.
The cracks are formed by performing a later-described energization forming process on the conductive thin film 16. In the crack,
Fine particles having a particle size of several hundred pm to several tens nm may be arranged. Note that it is difficult to accurately and accurately illustrate the actual position and shape of the electron-emitting portion, and therefore, it is schematically illustrated 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 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.
It is more preferable that the thickness be not more than nm.

Since it is difficult to accurately show the actual position and shape of the thin film 18, it is schematically shown in FIG. FIG. 4A shows an element from which a part of the thin film 18 has been removed.

The basic structure of the preferred element has been described above.
Here, an example using the following elements is shown.

Blue glass was used for the substrate 13, and Ni thin films were used for the device electrodes 14 and 15. The thickness d of the device electrode was 100 nm, and the electrode interval L was 2 μm.

As a main material of the fine particle film, Pd or P
Using dO, the thickness of the fine particle film is about 10 nm, and the width W is 10
nm.

Next, a description will be given of a preferred method of manufacturing a planar type surface conduction electron-emitting device. FIGS. 5 (a) to 5 (d)
FIG. 4 is a cross-sectional view for explaining a manufacturing process of the surface conduction electron-emitting device, in which notation of each member is the same as FIG.

1) First, device electrodes 14 and 15 are formed on a substrate 13 as shown in FIG.

In forming, the substrate 1
After sufficiently cleaning 3 with a detergent, pure water and an organic solvent, the material of the device electrode is deposited. (As a deposition method, for example, a vacuum film forming technique such as a vapor deposition method or a sputtering method may be used.) Then, the deposited electrode material is patterned by using a photolithography / etching technique.
A pair of device electrodes (14 and 15) shown in FIG.

2) Next, as shown in FIG. 5B, a conductive thin film 16 is formed.

In the formation, first, an organic metal solution is applied to the substrate (a), dried, heated and baked to form a fine particle film, and then patterned into a predetermined shape by photolithography and etching. . here,
The organic metal solution is a solution of an organic metal compound whose main element is a material of fine particles used for the conductive thin film 16. (Specifically, in this example, Pd was used as a main element.
In the embodiment, the dipping method is used as a coating method, but other methods such as a spinner method and a spray method may be used. As a method for forming the conductive thin film formed of the fine particle film 16, other than the method of applying the organometallic solution used in this embodiment, for example, a vacuum evaporation method, a sputtering method, or a chemical vapor deposition method In some cases, such as is used.

3) Next, as shown in FIG. 5C, an appropriate voltage is applied between the element electrodes 14 and 15 from the forming power supply 19 to perform the energizing forming process, and the electron emitting portion 17 is turned on. Form.

The energization forming treatment 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 An appropriate crack is formed in the thin film 18 in a portion of the conductive thin film 16 made of a fine particle film whose structure has been changed to a structure suitable for emitting electrons (that is, the electron emitting portion 17). 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. 6 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. Conductive thin film 16 made of fine particle film
Is preferable, a pulsed voltage is preferable. In the case of this example, a triangular wave pulse having a pulse width T1 is continuously applied at a pulse interval T2 as shown in FIG. 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 between triangular-wave pulses at appropriate intervals, and the current flowing at that time was measured by the ammeter 20.

In this example, for example, 10 ^-5 torr
Under a vacuum atmosphere of a degree, for example, the pulse width T1 is 1 millisecond, the pulse interval T2 is 10 milliseconds, and the peak value V
pf was raised by 0.1 V for each pulse. And
The monitor pulse Pm is inserted once every five pulses of the triangular wave are applied. The monitor pulse voltage Vpm was set to 0.1 V so as not to adversely affect the forming process. 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 becomes 1 × 10 ⁻⁷ A or less, The energization related to the forming process has been completed.

The above method is a preferable method for the surface conduction electron-emitting device of this embodiment, and for example, the design of the surface conduction electron-emitting device is changed such as the material and thickness of the fine particle film or the element electrode interval L. In such a case, it is desirable to appropriately change the energization conditions accordingly.

4) Next, as shown in FIG. 5D, an appropriate voltage is applied between the element electrodes 14 and 15 from the activating power supply 21 to carry out an energizing activation process, thereby obtaining an electron emission characteristic. Make improvements.

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 the figure, a deposit made of carbon or a carbon compound is schematically shown as a thin film 18.) By performing the activation process, the emission current at the same applied voltage is typically smaller than that before the activation. Specifically, it can be increased by 100 times or more.

Specifically, 10 ^-4 to 10 ^-5 torr
By applying a voltage pulse periodically in a vacuum atmosphere within the range, carbon or a carbon compound originating from an organic compound existing in the vacuum atmosphere is deposited. The thin film 18 is 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 30 nm or less.

FIG. 7A shows an example of an appropriate voltage waveform applied from the activation power supply 21 in order to explain 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, and the pulse width is T3.
Is 1 ms, and the pulse interval T4 is 10 ms. The above-mentioned 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, it is desirable to appropriately change the conditions accordingly.

Reference numeral 22 shown in FIG. 5D denotes an anode electrode for capturing an emission current Ie emitted from the surface conduction electron-emitting device, to which a DC high voltage power supply 23 and an ammeter 24 are 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 source 21, the current is The emission current Ie is measured by the total 24 to monitor the progress of the energization activation process, and the operation of the activation power supply 21 is controlled. An example of the emission current Ie measured by the ammeter 24 is shown in FIG. 7B. 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 the present embodiment. If the design of the surface conduction electron-emitting device is changed, the conditions should be changed accordingly. desirable.

As described above, the planar surface conduction electron-emitting device shown in FIG. 5E was manufactured.

(Vertical Type Surface Conduction Emission Element) FIG.
Another typical configuration of a surface conduction electron-emitting device 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 is shown. This FIG.
Is a schematic cross-sectional view for explaining a basic structure of a vertical type. In the figure, reference numeral 25 denotes a substrate, 26 and 27 denote device electrodes, 28 denotes a step forming member, and 29 denotes a conductive film using a fine particle film. A thin film 30 is an electron-emitting portion formed by an energization forming process, and 31 is a thin film formed by an energization activation process.

The difference between the vertical type and the flat type described above is that one (26) of the device electrodes is formed with a step forming member 28.
The conductive thin film 29 is provided on the step forming member 2.
8 is covered. Therefore, the element electrode interval L in the planar type shown in FIG. 4 is set as the step height Ls of the step forming member 28 in the vertical type. In addition,
For the substrate 25, the device 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 used in the same manner. The step forming member 28 is made of an electrically insulating material such as SiO ₂ .

(Characteristics of Surface Conduction Emission Device Used in Display Device) The device configuration and manufacturing method of the planar and vertical surface conduction electron-emitting devices have been described above. Next, the characteristics of the device used in the display device will be described. Is described.

FIG. 9 shows typical examples of (emission current Ie) versus (element applied voltage Vf) characteristics and (element current If) versus (element applied voltage Vf) characteristics of the elements used in the display device. 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, each of the two graphs is shown in arbitrary units.

The element used for the display device has the following three characteristics regarding the emission current Ie.

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, the non-linear element has 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 depends on the voltage Vf.
The magnitude of e can be controlled.

Third, since the response speed of the current Ie emitted from the device is faster than 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.

Because of the characteristics described above, the surface conduction electron-emitting device can be suitably used for a display device. For example, in a display device in which a large number of elements are provided corresponding to pixels of a display screen, if the first characteristic is used, display can be performed by sequentially scanning the display screen. That is,
The driving element has a threshold voltage Vth according to a desired light emission luminance.
The above voltage is appropriately applied, and a voltage lower than the threshold voltage Vth is applied to the non-selected elements. By sequentially switching the elements to be driven, the display screen can be sequentially scanned and displayed.

In addition, by using the second characteristic or the third characteristic, the light emission luminance can be controlled, so that gradation display can be performed.

(Structure of a multi-electron beam source in which a large number of elements are arranged in a simple matrix) Next, the structure of a multi-electron beam source in which the above-described surface conduction electron-emitting elements are arranged on a substrate and arranged in a simple matrix will be described.

FIG. 10 is a plan view of the multi-electron beam source used for the display panel of FIG. On the substrate, surface conduction type emission elements similar to those shown in FIG. 4 are arranged, and these elements are wired in a simple matrix by X-direction wiring electrodes 12 and Y-direction wiring electrodes 9. An insulating layer (not shown) is formed between the X-direction wiring electrodes 12 and the Y-direction wiring electrodes 9 at the intersections thereof to maintain electrical insulation.

FIG. 11 shows a cross section along the line AA 'in FIG.

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

[0097]

EXAMPLES In Reference Example 1 This reference example, first, to form a plurality of surface conduction electron source 1 not yet forming the rear plate 2. A cleaned blue plate glass was used as the rear plate 2, and 240 × 960 surface-conduction electron-emitting devices shown in FIG. The device electrodes 14 and 15 are Pt sputtered films, and the X-direction wires 9 and the Y-direction wires 12 are Ag wires formed by a screen printing method. The conductive thin film 16 is a PdO fine particle film obtained by firing a Pd amine complex solution.

As shown in FIG. 5B, 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 conductive material 5b is formed between the color phosphors 5a. In addition, a shape in which a portion for separating the pixels in the Y direction and providing a spacer 10 was added was used. First, a black conductive material 5b was formed, and a phosphor 5a of each color was applied to a gap portion between the black conductive material 5b to form a fluorescent film 5. As a material for the black stripe, a material mainly containing graphite, which is generally used, was used. Phosphor 5a on glass substrate 4
Was applied by a slurry method.

After the fluorescent film 5 is formed, the metal back 6 provided on the inner surface side of the fluorescent film 5 is subjected to a smoothing process (usually called filming) of the inner surface of the fluorescent film 5 and then to an Al film. Was prepared by vacuum evaporation. The face plate 7, to further enhance the conductivity of the fluorescent film 5, there is a case where the transparent electrode on the outer surface side of the fluorescent film 5 is provided, sufficient conductivity in only the metal back 6 is obtained in this reference example Omitted.

The spacer 10 is made of a first layer of cobalt oxide as an antistatic film 5c on an insulative substrate 10a (2.8 mm high, 200 μm thick, 40 mm long) made of cleaned soda lime glass. Two layers of yttrium oxide were formed by dipping.

The film of iron oxide and yttrium oxide used in the present reference example is a coating agent SYM of Kojundo Chemical Laboratory Co., Ltd.
Films were formed using FE05 and SYM-Y01, respectively. First, SYM-FE05 is applied on the spacer by dipping (pulling speed: 2 mm / sec),
After drying the first layer by drying at 120 ° C. and firing at 450 ° C., SYM-Y01 was diluted 4 times during dipping, and the insulating substrate 10a was pulled up at a speed of 0.4 mm / sec. Formed a second layer using the same method.

The spacer 10 is provided with an electrode 11 made of Al at a connection portion thereof in order to ensure connection with the X-direction wiring 9 or the metal back. This electrode 11 is X
50μ from direction wiring 9 to face plate 7
m, 30 from metal back 6 to rear plate 2
Four surfaces of the spacer 10 exposed in the envelope 8 in a range of 0 μm were completely covered. Spacers 10 on which a first layer of cobalt oxide and a second layer of yttrium oxide were formed as the antistatic film 10c were fixed on the X-directional wiring 9 at equal intervals.

Thereafter, the face plate 7 is arranged 2.8 mm above the electron source 1 via the side wall 3, and the rear plate 2, the face plate 7, the side wall 3 and the spacer 10
Was fixed.

The joint between the electron source 1 and the rear plate 2, the joint between the rear plate 2 and the side wall 3, and the face plate 7
A frit glass is applied to the joint between the side wall 3 and 430 ° C.
For 10 minutes or more for sealing.

The spacer 10 is made of a conductive frit glass containing silica spheres coated with Au on the black conductive material 5b (line width 300 μm) on the face plate 7 side. The continuity was secured.

The atmosphere in the envelope 8 completed as described above is exhausted by a vacuum pump through an exhaust pipe, and after reaching a sufficient degree of vacuum, the outer terminals Dx1 to Dxm and Dy1 to Dx1
A voltage was applied between the device electrodes 14 and 15 of the electron-emitting device 1 through yn, and the electron-emitting portion 18 was formed by conducting (forming) the electron-emitting portion forming thin film 16. The forming process was performed by applying a voltage having a waveform shown in FIG.

Next, 10 ^-3 ton of acetone was passed through the exhaust pipe.
rr is introduced into the vacuum container, and the external terminal Dx1
ＤDxm and Dy1 to Dyn were periodically applied with a voltage pulse to perform an activation process for depositing carbon or a carbon compound. The energization was activated by applying a waveform as shown in FIG.

Next, while heating the entire container to 200 ° C.,
After evacuating for 0 hour, the envelope was sealed by heating the exhaust pipe with a gas burner at a degree of vacuum of about 10 ^-6 torr.

Finally, gettering was performed to maintain the degree of vacuum after sealing.

In the image forming apparatus completed as described above, each electron-emitting device 1 has external terminals Dx1 to Dx
m, a scanning signal and a modulation signal are applied from a signal generating means (not shown) through Dy1 to Dyn to emit electrons, and a high voltage is applied to the metal back 6 through a high voltage terminal Hv to accelerate the emitted electron beam. Then, an image was displayed by causing electrons to collide with the fluorescent film 5 to excite and emit light from the phosphor. The voltage Va applied to the high voltage terminal Hv was 1 kV to 5 kV, and the voltage Vf applied between the device electrodes 14 and 15 was 14 V.

Regarding the spacer 10, the antistatic film 10c
Are shown in Table 1. Almost no change in the resistance value was observed even after passing through the steps of assembling, sealing to the face plate 7, sealing to the rear plate 2, evacuation, and energizing the element electrodes 14 and 15. This indicates that the film of iron oxide and yttrium oxide on iron oxide is very stable and suitable as an antistatic film. Table 1 shows the results.

[0112]

[Table 1] The iron oxide of the first layer had a temperature coefficient of resistance of -0.4, and there was no thermal runaway under the above driving conditions.
Spacer with yttrium oxide film as second layer
In (1), under the above driving conditions, the emission spot due to the electrons emitted from the electron-emitting device 1 was hardly displaced near the spacer, and was in a range where there was no problem as a television image. From the electron source closest to the
A phenomenon of shifting to the spacer side by about 4 to 1/5 occurred, and there was a problem as a television image.

[0113] (Reference Example 2) instead of iron oxide in the first layer of Example 1, referring to the film made of indium oxide (using SYM-in02) Example 1
A spacer 10 ((3)) was formed in the same manner as in Reference Example 1 except that a film was formed by the same film forming method. Table 1 shows the results. The spacer (3) using indium oxide had a low specific resistance value after the assembling process, could not apply Va up to 1 kV, and could not be used as a display.

REFERENCE EXAMPLE 3 Instead of iron oxide in the first layer of Reference Example 1, a mixture of chromium oxide and cobalt oxide (SYM-CR015, SYM
-CO04), hafnium oxide (SYM-HF0)
4 and mixing section for use) and cobalt oxide, except that was formed a film from the mixture in the same film forming method as in Reference Example 1 of tin oxide and hafnium oxide (using SYM-SN05) as in Reference Example 1 The spacer 10 ((4), (5), (6)) was prepared by the method described above.

[0115]

[Table 2] Under the above driving conditions, the spacers (4) and (5) hardly displaced the luminescent spot due to the electrons emitted from the electron-emitting device 1 near the spacer, and were in a range where there was no problem as a television image.

The spacer (6) has a temperature coefficient of resistance of-
The absolute value of 2.9 was large and thermal runaway occurred at Va = 5 kV. That is, when the spacer (6) is used, it is not practical as a display.

Reference Example 4 In the first layer of Reference Example 1, a mixture of zirconium oxide and zinc oxide (SYM-ZR04, S) was used instead of the iron oxide film.
YM-ZN20) at 5:95 and a second membrane
The yttrium oxide of the layer is not dipped but spinnered (500 rpm, 5 sec + 2000 rpm, 2 rpm).
A spacer 10 ((7)) was prepared in the same manner as in Reference Example 1 except that the coating was performed at 0 sec). Table 2 shows the results. Under the above-mentioned driving conditions, the spacer (7) had almost no shift of the luminescent spot near the spacer due to the electrons emitted from the electron-emitting device 1, and was in a range where there was no problem as a television image.

( Reference Example 5 ) The difference from Reference Example 3 (4) is that the spacer 10
Insulating substrate 10 made of cleaned soda-lime glass
a 0.5 μm zirconium oxide film is formed as a Na block layer 10 b on the substrate a, and an antistatic film 10 c is formed thereon.
Under the same conditions as in Reference Example 1, a spacer 10 ((8)) on which the first layer and the second layer were formed was formed. Table 3 shows the results. Spacer (8) is almost no deviation of the spacer near the light-emitting spot by electrons emitted from an electron-emitting device 1 of the above drive conditions, a range with no problem as a television image, Na blocking layer of Reference Example 3 (4) The same result as in the case without 10b was obtained.

[0119] (Reference Example 6) Reference Example 3 is different from (4), in the spacer 10,
Alumina was used in place of the insulating base material 10a made of soda lime glass, and a spacer 10 ((9)) having a first layer and a second layer was formed under the same conditions as in Reference Example 1. Table 3 shows the results. Spacer (9) is the deviation of the spacer near the light-emitting spot by electrons emitted from an electron-emitting device 1 in the above driving conditions little ranges no problem as a television image, Reference Example 3 of soda lime glass (4) Similar results were obtained as in the case.

[0120]

[Table 3] (Example 1 and Reference Example 7 ) In the second layer of Reference Example 1 (1), niobium oxide (using SYM-NB05), hafnium oxide, tungsten oxide (using SYM-W05), using a film made of a mixture of chromium and bismuth oxide (using SYM-B 105), reference example 3 this example in a manner similar to the spacer 10 ((10), (11), (12), (1
3), (14) ) and the spacer 10 ( (15)) of Reference Example 7 were prepared.

[0121]

[Table 4] The spacers (10), (11), (13), (14), and (15) have almost no displacement of the light emitting spot near the spacer due to the electrons emitted from the electron-emitting device 1 under the above-described driving conditions, which is a problem as a television image. There was no range, but spacer (12)
Since the thickness of niobium oxide in the second layer is large, the charge is not quickly released, the beam is attracted to the charged spacer, and electrons emitted from the nearest electron source from the spacer are reduced to about 1/1 / scanning line interval. About three times, a phenomenon of being sucked toward the spacer side occurred, and there was a problem as a television image.

( Reference Example 8 ) The difference from Reference Example 1 (1) is that a mixture of yttrium oxide and copper oxide (using SYM-CU04) (formed by dipping) is used instead of iron oxide in the first layer. The spacer 10 ((16)) was formed in the same manner as in Reference Example 1 (1) except that a film made of germanium oxide (using SYM-GE03) was formed to a thickness of 10 nm in place of yttrium oxide in the second layer by a spray method. )made. Table 5 shows the results. In the spacer (16), under the above-mentioned driving conditions, the emission spot due to the electrons emitted from the electron-emitting device 1 was hardly displaced near the spacer, and was in a range where there was no problem as a television image.

[0123]

[Table 5] ( Reference Example 9 ) The difference from Reference Example 1 (1) is that in the second layer, aluminum oxide (SYM-A104) was used instead of yttrium oxide.
Was used, and a spacer 10 ((17)) was formed in the same manner as in Reference Example 1. Table 5 shows the results. The spacer (17) was disturbed in an image near the spacer because the electron beam from the electron-emitting device 1 was attracted to the spacer (17) under the above driving conditions, and could not be used as a television image.

[0124]

As described above, according to the image forming apparatus of the present invention, the charge charged in the first layer is quickly released to the surface of the insulating member disposed between the element substrate and the face plate. A semiconductive transition metal oxide film, the second layer having insulating or semiconducting properties, a small secondary electron emission coefficient, and being difficult to be charged, and a transition metal oxide, bismuth oxide, or germanium oxide film Since the antistatic film has a two-layer structure made of an oxide, the disturbance of the potential of the beam near the spacer is suppressed, and the position where the beam collides with the phosphor and the phosphor that should emit light are Is prevented from occurring. As a result, luminance loss can be prevented, and clear television image display has become possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a part of an image forming apparatus of the present invention.

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

3A and 3B illustrate a phosphor array of a face plate of a display panel, wherein FIG. 3A is a plan view and FIG. 3B is an enlarged plan view of a part thereof.

FIGS. 4A and 4B schematically show a configuration of a planar surface conduction electron-emitting device, wherein FIG. 4A is a plan view and FIG.

FIG. 5 is a process chart showing a process of forming a planar surface conduction electron-emitting device.

FIG. 6 is a diagram showing an application pulse waveform for forming of an electron beam source.

FIGS. 7A and 7B are graphs showing waveforms of applied pulses in an energization activation step, wherein FIG. 7A is a graph showing an activation power supply output voltage, and FIG.

FIG. 8 is a sectional view of a vertical surface conduction electron-emitting device.

FIG. 9 is a graph showing the relationship between the device voltage, the device current, and the emission current of the surface conduction electron-emitting device.

FIG. 10 is a plan view showing a configuration of a multi-electron source arranged in a simple matrix.

11 is a sectional view taken along line A-A 'in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electron source 2 Rear plate 3 Side wall 4 Glass substrate 5 Fluorescent film 6 Metal back 7 Face plate 8 Enclosure 9 X direction wiring 10 Spacer 11 Electrode 12 Y direction wiring 13 Substrate 14, 15 Element electrode 16 Conductive thin film 17 Electron emission Part 18 Thin film formed by energization activation process 19 Forming power source 20 Ammeter 21 Activation power source 22 Discharge current Ie emitted from surface conduction type emission element
Anode electrode 23 for capturing electric current 23 DC high voltage power supply 24 Ammeter 25 Substrate 26, 27 Device electrode 28 Step forming member 29 Conductive thin film using fine particle film 30 Electron emitting portion formed by energization forming process 31 Energization activation process Thin film formed by

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 31/12 H01J 29/87 H01J 31/15 H01J 29/86 H01J 9/24 H01J 9/02

Claims (11)

(57) [Claims] A substrate on which a plurality of electron-emitting devices are formed;
The transparent substrate on which the luminescent material is formed
In the image forming apparatus having a structure facing each other,
Pacer is made of insulating base material and transition gold
A first layer made of a metal oxide and a layer provided outside the first layer
Niobium oxide, hafnium oxide, tungsten oxide
Or a second layer comprising a mixture thereof.
The image forming apparatus, wherein the thickness of the second layer is 5 nm to 30 nm . 2. A substrate having a plurality of electron-emitting devices formed thereon,
The transparent substrate on which the luminescent material is formed
In the image forming apparatus having a structure facing each other,
Pacer is made of insulating base material and transition gold
A first layer made of a metal oxide and a layer provided outside the first layer
Niobium oxide, hafnium oxide, tungsten oxide
Or a second layer made of a mixture thereof, wherein the insulating base is made of glass containing Na, and between the insulating base and the metal oxide film of the first layer, image forming apparatus characterized by silicon oxide film, zirconium oxide film or aluminum oxide film blocking layer, is provided. Wherein the metal oxide constituting the first layer of iron oxide, cobalt oxide, copper oxide, ruthenium oxide, and an image forming according to claim 1 or 2 a mixture thereof with other transition metals apparatus. 4. The image forming apparatus according to claim 1, wherein the first layer has a thickness of 10 nm to 1 μm. Wherein said second layer to claim 1 which is an insulator
The image forming apparatus according to any one of the three. 6. The method according to claim 1, wherein the insulating substrate is glass.
The image forming apparatus according to any one of claims 1 to 5 , wherein Wherein said insulating base, an image forming apparatus according to any one of claims 1 to 6, which is a ceramic of the alumina as a component. Wherein said spacer is an image forming apparatus according to any one of claims 1 to 7 is electrically connected to the arranged electron source drive wires in a matrix. 9. The image forming apparatus according to any one of the spacer emission electron acceleration claim electrodes are electrically connected to 1-8. 10. An image forming apparatus according to any one of the cold cathode electron-emitting devices are surface conduction electron-emitting claims 1 to 9 which is an element. 11. The first layer is dried and fired after applying a dispersion of metal oxide fine particles or a solution of a sol composed of metal alkoxides, organic acid metal salts, and derivatives thereof to the substrate. Wherein the second layer is a dispersion of fine particles of niobium oxide, hafnium oxide, tungsten oxide, or a mixture thereof, or a metal alkoxide, an organic acid metal salt, and a mixture thereof. The image forming apparatus according to any one of claims 1 to 10 , wherein a film of a sol solution including a derivative is applied to the substrate and then dried and fired to form a film.