JP2000123764A - Image forming device using electron emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the orbit of an electron beam by preventing the center of a luminescent spot by the radiation of the electron beam on a phosphor target from being located in the normal line direction of the insulation face on an electron substrate. SOLUTION: The drift quantity ΔX1 to the tip section of a luminescent spot 78, the drift quantity ΔX2 to the tail section of the luminescent spot 78 and the size in the direction Y of an electron beam spot on an image forming member face can be expressed by parameters of Va, Vf and H based on the study of the shape and size of the luminescent spot 78 and the position drift in the direction X from the vertical above of an electron emission section 74 (Va is an electron accelerating power supply, Vf is an element driving power supply and H is the distance of an electron source substrate). When Vf, Va and H are properly selected or the electron source substrate is formed so that the coordinates ΔX of the center of the obtained base point are not located in the normal line direction of the insulation face of the electron source substrate, the disturbance of an image or the deterioration of an element caused by an electric discharge can be prevented. The orbit of an electron beam can be stabilized by properly determining Va, Vf, H or the structure of the electron source substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as an image display apparatus using an electron source having a plurality of surface conduction electron-emitting devices.

[0002]

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

[0003] As an example of the FE type, W. P. Dyke
& W. W. Dolan, "Field emissi
on ", Advance in Electron P
physics, 8, 89 (1956) or C.I. A.
Spindt, “PHYSICAL Propertyi
es of thin-film field emi
session cathodes with mollyb
denium cones ", J. Appl. Phys.
s. , 47, 5248 (1976).

As an example of the MIM type, C.I. A. M
ead “Operation of Tunnel-Em
issue Devices ", J. Apply. P.
hys. , 32, 646 (1961).

Further, as an example of the surface conduction type electron-emitting device type, M.S. I. Elinson, Recio Eng.
Electron Phys. , 10, 1290, (1
965).

[0006] The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows through 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 and the like and a device using an Au thin film [G. Dittmer: "Thin SolidFi
lms ", 9,317 (1972)] , In 2 O 3 / S
nO ₂ thin film [M. Hartwell and
C. G. FIG. Fonstad: "IEEE Trans.
ED Conf. "519 (1975)], using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1,
22 (1983)].

As a typical example of these surface conduction electron-emitting devices, the above-mentioned M.P. Figure 1 shows the device configuration of Hartwell
Is shown schematically in FIG. In FIG. 1, reference numeral 1 denotes a substrate,
Reference numeral 4 denotes a conductive thin film, which is formed of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern, and the electron emission portion 5 is formed by an energization process called energization forming described later. Note that the element electrode interval L in the figure is 0.5 to 1
mm and W are set to 0.1 mm.

Conventionally, in these surface conduction electron-emitting devices, an electron-emitting portion 5 is formed by performing an energization process called energization forming on the conductive thin film 4 before performing electron emission. Was common. That is, the energization forming means a DC voltage or a very slowly increasing voltage, for example, 1 V /
This means that the conductive thin film is locally destroyed, deformed or deteriorated by applying a current for about a minute to form the electron emitting portion 5 in an electrically high resistance state. Note that the electron-emitting portion 5 is a part of the conductive thin film 4 in which a crack has occurred, and emits electrons from the vicinity of the crack. The surface conduction type electron-emitting device that has been subjected to such an energization forming process is one in which a voltage is applied to the above-described conductive thin film 4 and a current is caused to flow through the device to cause the electron-emitting portion 5 to emit electrons.

The above-mentioned surface conduction electron-emitting device has a simple structure and is easy to manufacture.
There is an advantage that a large number of elements can be arranged and formed. Therefore, various applications that can take advantage of this feature are being studied. For example, there are a charged beam source and a display device. In particular, in an image forming apparatus such as an image display apparatus, a flat panel display apparatus using a liquid crystal has been widely used in place of a CRT in recent years. However, since it is not a self-luminous type, it is necessary to have a backlight. Therefore, development of a self-luminous display device has been desired. In this regard, a self-luminous display device is a combination of the above-described electron source having a large number of surface conduction electron-emitting devices and a phosphor that emits visible light by electrons emitted from the electron source. An image forming apparatus which is an image display apparatus is advantageous (see, for example, US Pat. No. 5,066,883).

FIG. 7 is a basic configuration diagram of an image forming apparatus using a surface conduction electron-emitting device. 7, reference numeral 21 denotes an electron source substrate on which an electron-emitting device is formed, 31 denotes a rear plate to which the electron source substrate 21 is fixed, and 36 denotes a face on which a fluorescent film 34 and a metal back 35 are formed on the inner surface of a glass substrate 33. Reference numeral 32 denotes a support frame, and the rear plate and the face plate constitute an envelope 37 at a distance H. Also, in FIG.
Reference numeral 24 corresponds to the electron-emitting portion in FIG. 1, and reference numerals 22 and 23 are X-direction wiring and Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device.

In the above-described image forming apparatus, when an acceleration voltage Va is applied to the metal back 35 and a predetermined voltage Vf is applied between the electrodes 2 and 3 at the same time, an electron beam is emitted from the electron emission portion 24 and the phosphor target Emits light.

[0012]

However, in the case of an image forming apparatus using a surface conduction electron-emitting device, the trajectory of the electron beam is not always stable, and the shape of the luminescent spot of the phosphor changes. The quality of the displayed image deteriorates, which is inconvenient. This is because the potential of the insulating substrate 1 provided with the surface conduction electron-emitting device is unstable, and the electron beam is affected by the unstable potential.

Although the cause of the potential instability is still unknown, it is caused by charging by electrons emitted from the surface conduction electron-emitting device, or generated by members constituting the surface conduction electron-emitting device. It is considered that the charge is caused by ions. to solve this problem,
On the insulating substrate surface around the electron-emitting device, a potential regulating means for regulating the surface potential is provided to stabilize the potential of the substrate surface,
A method for stabilizing the trajectory of an electron beam has already been proposed (see Japanese Patent Application Laid-Open No. 1-283735).

However, in the case of an image forming apparatus using an electron source substrate on which a large number of surface conduction electron-emitting devices are arranged, insulation between wirings is maintained, or positional accuracy in manufacturing technology is increased by forming the wiring in a large area. From the limit, it was practically difficult to provide the potential regulating means on the entire insulating surface. For this reason, exposure of the insulating surface on the electron source substrate is unavoidable, and the trajectory of the electron beam may become unstable.

When the face plate is irradiated with electrons, the positively ionized molecules are released in the electric field by the electron acceleration power supply Va due to gas release and ionization by the impurity molecules adsorbed on the face plate. Accelerated. It has been observed that the positive ions charge the insulating surface on the electron source substrate. This charge amount is extremely large on the insulating surface in the direction normal to the electron irradiation position of the face plate, and rapidly decreases depending on the distance from this position. If the bright spot on the face plate due to the electron irradiation is located near the normal direction of the electron emitting portion, the electron source substrate in the normal direction is covered with a conductive material such as an electrode or a thin film for forming the electron emitting portion. Therefore, charging of the electron source substrate is suppressed.

However, in the surface conduction electron-emitting device, the electric field generated by the potential accelerating power supply Va is distorted by the electric field generated by the device driving power supply Vf. Not formed in the line direction. Therefore, if the position of the luminescent spot due to electron irradiation is located in the normal direction of the insulating surface of the electron source substrate, the charging of the insulating surface becomes remarkable, and the trajectory of the electron beam becomes unstable. Particularly, in a thin image forming apparatus, since the distance H between the face plate and the electron source substrate is extremely close, the potential rise due to charging is remarkable, and in the worst case, the element is deteriorated by the discharge.

The present invention has been made on the basis of the above circumstances, and an object thereof is to focus on the fact that the position of a luminescent spot on a face plate by electron irradiation is determined by Va, Vf, and H. It is an object of the present invention to provide an image forming apparatus having a stable electron beam trajectory.

[0018]

Therefore, in the present invention,
1. An image forming apparatus comprising: an electron source substrate having a plurality of surface conduction electron-emitting devices provided on a substrate; and a face plate having opposing phosphor targets to be irradiated with electron beams from the surface conduction electron-emitting devices. At
The luminance center of a luminescent spot on the phosphor target due to the irradiation of the electron beam is not located in a direction normal to an insulating surface on the substrate.

[0019]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic view showing a configuration of a surface conduction electron-emitting device to which the present invention can be applied. FIG. 1 (a) is a plan view and FIG. 1 (b) is a cross-sectional view.
In FIG. 1, reference numeral 1 denotes a substrate, 2 and 3 denote device electrodes, 4 denotes a conductive thin film, and 5 denotes an electron emitting portion. The substrate 1 is made of quartz glass, glass having a reduced impurity content such as Na, blue plate glass, a glass substrate formed by laminating SiO ₂ on a blue plate glass by sputtering, ceramics such as alumina, and Si. A substrate or the like can be used.

The material of the opposing device electrodes 2 and 3 is
In this case, a general conductor material can be used. this
Is, for example, Ni, Cr, Au, Mo, W, Pt, T
metals such as i, Al, Cu, Pd or alloys thereof, and
And Pd, Ag, Au, RuO _Two, Pd-Ag, etc.
Consists of metal or its metal oxide and glass
Printed conductor, In_TwoO_Three-SnO_TwoSuch as transparent conductors
And semiconductor materials such as polysilicon.
Can be

The element electrode interval L, the element electrode length W, the shape of the conductive thin film 4, and the like are designed in consideration of the form to be applied. The element electrode interval L can be preferably in the range of several hundred nm to several hundred μm, more preferably,
It can be in the range of several μm to several tens μm.

The length W of the device electrode can be in the range of several μm to several hundred μm in consideration of the resistance value of the electrode and the electron emission characteristics. The film thickness d of the device electrodes 2 and 3 is several tens n.
m to several μm. In addition, not only the configuration shown in FIG. 1 but also a configuration in which the conductive thin film 4 and the opposing element electrodes 2 and 3 are laminated on the substrate 1 in this order.

As the conductive thin film 4, a fine particle film composed of fine particles is preferably used in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of the step coverage to the device electrodes 2 and 3, the resistance value between the device electrodes 2 and 3, the forming conditions described later, and the like.
Usually, it is preferably in the range of several times 0.1 nm to several hundred nm, more preferably in the range of 1 nm to 50 nm. The resistance value of Rs is 102 to 1
It is a value of 07Ω / □. Rs has a thickness t and a width w.
This is the amount that appears when the resistance R of the thin film having a length of 1 is R = Rs (l / w). Here, the forming process has been described using the energizing process as an example, but the forming process is not limited to this.
It includes a process for forming a high resistance state by causing a crack in the film.

The material constituting the conductive thin film 4 is Pd, P
t, Ru, Ag, Au, Ti, In, Cu, Cr, F
e, Zn, Sn, Ta, W, Pd and other metals, PdO,
SnO_Two, In_TwoO_Three, PbO, Sb_TwoO_ThreeSuch as oxidation
Object, HfB_Two, ZrB_Two, LaB ₆, CeB₆, Y
B_Four, GdB_FourBoride such as TiC, ZrC, Hf
Carbides such as C, Ta, C, SiC, WC, TiN, Z
nitrides such as rN and HfN, semiconductors such as Si and Ge,
It is appropriately selected from carbon and the like.

The fine particle film described here is a film in which a plurality of fine particles are aggregated, and has a fine structure in a state in which the fine particles are individually dispersed or arranged, or in a state in which the fine particles are adjacent to each other or overlap each other (some fine particles). Gather together to form an island-like structure as a whole). The particle size of the fine particles is from several times 0.1 nm to several hundred nm.
, Preferably in the range of 1 nm to 20 nm.

Here, since the word "fine particles" is frequently used, its meaning will be described. That is, small particles are called “fine particles”, and smaller ones are called “ultra fine particles”. In general, it is widely known that a particle having a size smaller than that of the “ultra-fine particles” and having a number of atoms of about several hundreds or less is referred to as a “cluster”.

However, the boundaries are not strict and differ depending on what kind of property is focused on. Also, “fine particles” and “ultra fine particles”
May be collectively referred to as “fine particles”, and the description herein is in line with this. This is described in detail in "Experimental Physics Course 14: Surfaces and Particles" (edited by Yoshio Kinoshita, published by Kyoritsu Shuppan, September 1, 1986). In other words, "the term" fine particles "used herein means a diameter of about 2 to 3 μm to about 10 nm, and especially the term" ultrafine particles "means a particle size of about 10 nm to about 2 to 3 nm. Since both are collectively written as particles, they are not exact and are only a rough guide.If the number of atoms constituting a particle is from 2 to several tens to several hundreds, It is referred to as a cluster. "(Pages 195 to 226).

Further, in addition, in the definition of "ultra fine particles" in the "Hayashi / Ultra Fine Particle Project" of the New Technology Development Corporation, the lower limit of the particle size is specified to be smaller, as follows. That is, in the “Ultrafine Particle Project” of the Creative Science and Technology Promotion System (1981 to 1986), particles having a size (diameter) in the range of about 1 to 100 nm are referred to as “ultrafine particles”.
e). Then, one ultrafine particle is an aggregate of about 100 to 108 atoms. In terms of atomic scale, ultrafine particles are large to giant particles. ("Ultra Fine Particles-Creative Science and Technology-" Hayashi Tax, Ryoji Ueda, Akira Tazaki, ed., Mita Publishing, 1988, page 2
(4th line) “A particle smaller than ultrafine particles, that is, a single particle composed of several to several hundred atoms is usually called a cluster” (p. 2, lines 12 to 13 of the same book).
It is described.

[0029] Based on the general notation as described above,
In this specification, the term "fine particles" refers to an aggregate of a large number of atoms and molecules, and the lower limit of the particle size is from several times 0.1 nm to about 1 nm, and the upper limit is about several μm.

The electron-emitting portion 5 is constituted by a high-resistance crack formed in a part of the conductive thin film 4 and is formed by a method such as the film thickness, film quality and material of the conductive thin film 4 and energization forming which will be described later. Depends. In some cases, conductive fine particles having a particle diameter in the range of several times 0.1 nm to several tens of nm are present inside the electron-emitting portion 5. The conductive fine particles contain some or all of the elements of the material constituting the conductive thin film 4. The electron emitting portion 5 and the conductive thin film 4 in the vicinity thereof can also contain carbon and a carbon compound.

There are various methods for manufacturing the above-mentioned surface conduction electron-emitting device. One example is schematically shown in FIG. In FIG. 2, the same parts as those shown in FIG. 1 are denoted by the same reference numerals.

1) The substrate 1 is sufficiently washed with a detergent, pure water, an organic solvent, and the like, and an element electrode material is deposited by a vacuum evaporation method, a sputtering method, or the like. Device electrodes 2 and 3 are provided on a substrate 1.
(See FIG. 2A).

2) An organic metal solution is applied to the substrate 1 provided with the device electrodes 2 and 3 to form an organic metal thin film. As the organic metal solution, a solution of an organic metal compound containing the metal of the material of the conductive film 4 as a main element can be used. Then, the organic metal thin film is heated and baked, and is patterned by lift-off, etching, or the like to form a conductive thin film 4 (see FIG. 2B). Here, the method of applying the organometallic solution has been described, but the method of forming the conductive thin film 4 is not limited thereto, but may be a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion method, or the like. A coating method, a dipping method, a spinner method, or the like can also be used.

3) Subsequently, a forming process is performed. As an example of a method of the forming process, a method by an energization process will be described. When a current is applied between the device electrodes 2 and 3 using a power supply (not shown), an electron-emitting portion 5 having a changed structure is formed at a portion of the conductive thin film 4 (FIG. 2C).
See). According to the energization forming, a portion of the conductive thin film 4 having a locally changed structure such as destruction, deformation or alteration is formed. This portion constitutes the electron emission portion 5.

FIG. 3 shows an example of the voltage waveform of the energization forming. The voltage waveform is preferably a pulse waveform. For this purpose, a method shown in FIG. 3A in which a pulse with a constant pulse peak value is applied continuously and a method shown in FIG. 3B in which a voltage pulse is applied while increasing the pulse peak value are used. There are the methods shown.

T1 and T2 in FIG.
The pulse width and pulse interval of the voltage waveform. Normally T1 is 1
μsec to 10 msec, and T2 is 10 μs
ec is set in the range of 10 msec. The peak value of the triangular wave (peak voltage at the time of energization forming) is appropriately selected according to the form of the surface conduction electron-emitting device. Under such conditions, for example, a voltage is applied for several seconds to several tens minutes. Note that the pulse waveform is not limited to a triangular wave, and a desired waveform such as a rectangular wave can be adopted. T1 and T2 in FIG. 3B can be the same as those shown in FIG. 3A. The peak value of the triangular wave (peak voltage at the time of energization forming) is, for example, 0.
It can be increased by about 1 V step.

The end of the energization forming process can be detected by applying a voltage that does not locally destroy or deform the conductive thin film 2 during the pulse interval T2, and measuring the current. For example, an element current flowing by applying a voltage of about 0.1 V is measured, and a resistance value is obtained. When the resistance shows 1 MΩ or more, the energization forming is terminated.

4) It is preferable to perform a process called an activation process on the element after the forming. The activation process means that the device current If and the emission current Ie are
This is a step that changes significantly (to be described later, see FIG. 4). The activation treatment can be performed, for example, by repeatedly applying a pulse under an atmosphere containing a gas of an organic substance, similarly to the energization forming. This atmosphere is
For example, when the inside of a vacuum vessel is evacuated using an oil diffusion pump or a rotary pump, the organic gas can be formed using the organic gas remaining in the atmosphere, and once sufficiently evacuated by an ion pump or the like. It can also be obtained by introducing a gas of an appropriate organic substance into a vacuum.

The preferable gas pressure of the organic substance at this time varies depending on the above-mentioned application form, the shape of the vacuum vessel, the type of the organic substance, and the like, and is appropriately set according to the case. Suitable organic substances include organic acids such as alkanes, alkenes, aliphatic hydrocarbons of alkynes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxylic acids and sulfonic acids. And specifically, C such as methane, ethane, and propane
saturated hydrocarbons represented by _n H _{2n + 2} , unsaturated hydrocarbons represented by a composition formula such as C _n H _2n such as ethylene and propylene, benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, Methylamine, ethylamine, phenol, formic acid, acetic acid, propionic acid and the like, or a mixture thereof can be used.

By this treatment, carbon or a carbon compound is deposited on the device from organic substances existing in the atmosphere,
As described above, the element current If and the emission current Ie significantly change. The end of the activation process is appropriately determined while measuring the element current If and the emission current Ie. Here, the pulse width, pulse interval, pulse crest value, and the like are set as appropriate.

Carbon and carbon compounds include, for example, graphite (including so-called HOPG ', PG, and GC;
OPG is a crystal structure of almost perfect graphite, PG is a crystal having a crystal grain of about 200 angstroms and a little disordered, and GC is a crystal having a crystal grain of about 20 angstroms and a disorder of the crystal structure is further increased.) ,
Amorphous carbon (refers to amorphous carbon and a mixture thereof with the microcrystals of graphite);
The film thickness is preferably within a range of 50 nm or less.
It is more preferable to set the range to 0 nm or less.

5) It is preferable that the electron-emitting device obtained through such a process is subjected to a stabilization process. This process is a step of exhausting the organic substance in the vacuum container.
It is preferable to use a vacuum exhaust device that does not use oil so that the oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum exhaust device such as a sorption pump or an ion pump can be used.

In the above-described activation process, when an oil diffusion pump or a rotary pump is used as an exhaust device, and an organic gas derived from an oil component generated from the oil diffusion pump is used, the partial pressure of this component is kept as low as possible. There is a need. The partial pressure of the organic component in the vacuum vessel is preferably 1.3 × 10 ⁻⁶ Pa or less, particularly 1.3 × 10 ⁻⁸ Pa or less, at a partial pressure at which the above-mentioned carbon and carbon compounds are not newly deposited. More preferred.

When the inside of the vacuum vessel is further evacuated, it is preferable to heat the entire vacuum vessel so that the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device can be easily evacuated.
The heating condition at this time is 80 to 250 ° C., preferably 1 to
It is desirable to perform the treatment at 50 ° C. or higher for as long as possible, but the treatment is not particularly limited to this condition, and the treatment is performed under conditions appropriately selected from various conditions such as the size and shape of the vacuum vessel and the configuration of the electron-emitting device. . The pressure in the vacuum vessel needs to be as low as possible, and is preferably 1 × 10 ⁻⁵ Pa or less, more preferably 1.3 × 10 ⁻⁶ Pa or less.

The driving atmosphere after the stabilization process is as follows.
It is preferable to maintain the atmosphere at the end of the stabilization process,
The present invention is not limited to this, and if the organic substance in the atmosphere is sufficiently removed, sufficiently stable characteristics can be maintained even if the degree of vacuum itself is slightly reduced. By employing such a vacuum atmosphere, the deposition of new carbon or a carbon compound can be suppressed, and H ₂ O, O _2, etc. adsorbed on a vacuum vessel or a substrate can be removed. As a result, the device current If , The emission current Ie is stabilized.

Next, basic characteristics of the electron-emitting device of the present invention obtained through the above-described processing steps will be described with reference to FIGS. FIG. 5 is a schematic diagram showing an example of a vacuum processing apparatus, and this vacuum processing apparatus also has a function as a measurement evaluation apparatus. In FIG. 5, the same parts as those shown in FIG. 1 are denoted by the same reference numerals. In FIG. 5, 55 is a vacuum vessel, and 56 is an exhaust pump. An electron-emitting device is provided in the vacuum vessel 55.

That is, reference numeral 1 denotes a substrate constituting an electron-emitting device, reference numerals 2 and 3 denote device electrodes, reference numeral 4 denotes a conductive thin film, and reference numeral 5 denotes an electron-emitting portion. 51 is a device voltage V applied to the electron-emitting device.
f, an ammeter for measuring an element current If flowing through the conductive thin film 4 between the element electrodes 2 and 3, and 54 an emission current I emitted from an electron emission portion of the element.
This is an anode electrode for capturing e. Reference numeral 53 denotes a high-voltage power supply for applying a voltage to the anode electrode 54, and reference numeral 52 denotes an ammeter for measuring an emission current Ie emitted from the electron emission section 5 of the device. For example, the measurement can be performed with the voltage of the anode electrode in the range of 1 kV to 10 kV and the distance H between the anode electrode and the electron-emitting device in the range of 2 mm to 8 mm.

A vacuum gauge (not shown) is provided in the vacuum vessel 55.
Such devices as those required for measurement in a vacuum atmosphere are provided so that measurement and evaluation in a desired vacuum atmosphere can be performed. The exhaust pump 56 includes a normal high vacuum device system including a turbo pump and a rotary pump, and an ultrahigh vacuum device system including an ion pump and the like. The entire vacuum processing apparatus provided with the electron source substrate shown here can be heated up to 250 ° C. by a heater (not shown). Therefore, if this vacuum processing apparatus is used, the steps after the energization forming described above can also be performed.

FIG. 4 shows emission current Ie, element current If and element voltage V measured in the vacuum processing apparatus shown in FIG.
It is the figure which showed the relationship of f typically. In FIG.
Since the emission current Ie is significantly smaller than the element current If, it is shown in arbitrary units. The vertical and horizontal axes are linear scales. As is clear from FIG. 4, the surface conduction electron-emitting device to which the present invention can be applied has three characteristic properties with respect to the emission current Ie. That is, (i) the emission current Ie increases sharply when an element voltage higher than a certain voltage (referred to as a threshold voltage, Vth in FIG. 4) or more is applied, whereas when the element voltage is lower than the threshold voltage Vth, the emission current Ie is increased. Ie is hardly detected. That is, the emission current Ie
Is a non-linear element having a clear threshold voltage Vth.

(Ii) Since the emission current Ie depends monotonically on the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf.

(Iii) The emission charge captured by the anode electrode 54 depends on the time during which the device voltage Vf is applied. That is, the amount of charge captured by the anode electrode 54 can be controlled by the time during which the device voltage Vf is applied.

As understood from the above description, the surface conduction electron-emitting device to which the present invention can be applied can easily control the electron emission characteristics in accordance with the input signal. Utilizing this property enables application to various fields such as an electron source and an image forming apparatus configured by disposing a plurality of electron-emitting devices.

In FIG. 4, an example in which the element current If monotonically increases with respect to the element voltage Vf (hereinafter referred to as "MI characteristic") is shown by a solid line. The element current If may exhibit a voltage-controlled negative resistance characteristic (hereinafter, referred to as “VCNR characteristic”) with respect to the element voltage Vf. These characteristics can be controlled by controlling the aforementioned steps.

Next, application examples of the electron-emitting device according to the present invention will be described below. Here, a plurality of the above-described surface conduction electron-emitting devices are arranged on a substrate to form, for example, an electron source or an image forming apparatus. Various arrangements of the electron-emitting devices can be adopted.

As an example, the electron-emitting device is set in the X direction and the Y direction.
One of the electrodes of the plurality of electron-emitting devices arranged in a matrix in the direction, and one of the electrodes of the plurality of electron-emitting devices arranged in the same row is commonly connected to the wiring in the X direction, and the electrodes of the plurality of electron-emitting devices arranged in the same column Is commonly connected to the wiring in the Y direction.
Such is a so-called simple matrix arrangement, which will be described in detail below.

As described above, the surface conduction electron-emitting device according to the present invention has the following characteristics (i) to (iii). That is, the electrons emitted from the surface conduction electron-emitting device are
Above the threshold voltage, it can be controlled by the peak value and width of the pulse voltage applied between the opposing element electrodes. On the other hand, when the voltage is equal to or lower than the threshold voltage, it is hardly emitted. According to this characteristic, even when a large number of electron-emitting devices are arranged, if a pulse-like voltage is appropriately applied to each of the devices, a surface-conduction electron-emitting device is selected according to an input signal to emit electrons. You can control the amount.

Hereinafter, based on this principle, an electron source substrate obtained by arranging a plurality of electron-emitting devices to which the present invention can be applied will be described. In FIG. 6, reference numeral 21 denotes an electron source substrate,
22 is an X-direction wiring, and 23 is a Y-direction wiring. Reference numeral 24 denotes a surface conduction electron-emitting device, and reference numeral 25 denotes a connection.

The m X-directional wirings 22 are Dx1, Dx
2,... Dxm, and can be formed of a conductive metal formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The material, thickness and width of the wiring are appropriately designed. The Y-direction wiring 23 includes n wirings Dy1, Dy2,... Dyn, and is formed in the same manner as the X-direction wiring 22. These m
An interlayer insulating layer (not shown) is provided between the X-directional wirings 22 and the n-directional wirings 23 to electrically separate them (m and n are both positive). Integer).

This interlayer insulating layer is formed by a vacuum deposition method, a printing method,
It is composed of a material such as SiO ₂ formed by using a sputtering method or the like. For example, a film having a desired shape is formed on a part of the entire surface of the substrate 21 on which the X-directional wiring 22 is formed. In particular, the film is formed so as to withstand the potential difference at the intersection of the X-directional wiring 22 and the Y-directional wiring 23. The thickness, material, and manufacturing method are appropriately set. Note that the X-direction wiring 22 and the Y-direction wiring 23
Each is drawn out as an external terminal.

A pair of electrodes (not shown) constituting the surface conduction electron-emitting device 24 are electrically connected by m X-directional wires 22, n Y-directional wires 23, and a connection 25 made of a conductive metal or the like. Connected. Wiring 22 and Wiring 23
, The material forming the connection 25, and the material forming the pair of device electrodes may have some or all of the same or different constituent elements. These materials are appropriately selected, for example, from the above-described materials for the device electrodes. In the case where the material forming the element electrode is the same as the wiring material, the wiring connected to the element electrode can be called an element electrode, in other words.

A scanning signal applying means (not shown) for applying a scanning signal for selecting a row of the surface conduction electron-emitting devices 24 arranged in the X direction is connected to the X-direction wiring 22. On the other hand, a modulation signal generating means (not shown) for modulating each column of the surface conduction electron-emitting devices 24 arranged in the Y direction according to an input signal is connected to the Y-direction wiring 23. . The driving voltage applied to each electron-emitting device is supplied as a difference voltage between a scanning signal and a modulation signal applied to the device. In the above configuration, individual elements can be selected and driven independently using a simple matrix wiring.

FIGS. 7 and 8 show an image forming apparatus constructed using such an electron source having a simple matrix arrangement.
This will be described with reference to FIG. FIG. 7 is a schematic diagram illustrating an example of a display panel of the image forming apparatus, and FIG. 8 is a schematic diagram of a fluorescent film used in the image forming apparatus of FIG.

In FIG. 7, reference numeral 21 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged, 31 denotes a rear plate on which the electron source substrate 21 is fixed, and 36 denotes a glass substrate 33 on which an inner surface of a fluorescent film 34 and a metal back 35 are provided. It is a formed face plate. Reference numeral 32 denotes a support frame, and the rear plate 31 and the face plate 36 are joined to the support frame 32 by using low melting point frit glass or the like as a sealing material.
Reference numeral 24 corresponds to the electron-emitting portion in FIG.
Reference numerals 22 and 23 are an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device.

The envelope 37 is composed of the face plate 36, the support frame 32, and the rear plate 31, as described above. Since the rear plate 31 is provided mainly for the purpose of reinforcing the strength of the substrate 21, if the substrate 21 itself has sufficient strength, the separate rear plate 31 becomes unnecessary.
That is, the support frame 32 may be sealed directly to the substrate 21, and the face plate 36, the support frame 32 and the substrate 21 may constitute the entire envelope.

On the other hand, a support (not shown) called a spacer is provided between the face plate 36 and the rear plate 31.
, The envelope 37 having sufficient strength against the atmospheric pressure can be configured.

FIG. 8 is a schematic diagram showing the fluorescent film 34.
The fluorescent film 34 can be composed of only a phosphor in the case of monochrome, but in the case of a color phosphor film, a black stripe (FIG. 8A)
) Or a black matrix (see FIG. 8B) and a phosphor 39. The purpose of providing the black stripes and the black matrix is to make the color separation between the phosphors 39 of the necessary three primary color phosphors black in the case of color display, thereby making the color mixture and the like inconspicuous.
4 is to suppress a decrease in contrast due to external light reflection. As a material for the black stripe, a material having conductivity and having little light transmission and reflection can be used in addition to a material mainly containing graphite which is generally used.

As a method of applying the phosphor 34 on the glass substrate 33, a precipitation method, a printing method, or the like can be adopted regardless of monochrome or color. On the inner surface of the fluorescent film 34,
Usually, a metal back 35 is provided. The purpose of providing the metal back is to improve the brightness by reflecting the light toward the inner surface side of the light emitted from the phosphor to the face plate 36 side, thereby improving the brightness and acting as an electrode for applying an electron beam acceleration voltage. And protecting the phosphor from damage due to collision of negative ions generated in the envelope 37. In addition, the metal back, after the fluorescent film is made,
The fluorescent film can be formed by performing a smoothing process (usually called “filming”) on the inner surface of the fluorescent film, and then depositing Al using vacuum deposition or the like. Further, in the face plate 36, a transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 34 in order to further increase the conductivity of the fluorescent film 34. Furthermore, when performing the above-mentioned sealing, in the case of color display, it is necessary to make each color phosphor correspond to the electron-emitting device, and sufficient alignment is indispensable.

Next, an example of a method for manufacturing the image forming apparatus shown in FIG. 7 will be described with reference to FIG. FIG. 9 schematically shows an outline of an apparatus used for a process in this manufacturing method. Here, the image forming apparatus 131 is connected to a vacuum chamber 133 via an exhaust pipe 132 and further connected to an exhaust apparatus 135 via a gate valve 134. The vacuum chamber 133 has a pressure gauge 136 to measure the internal pressure and the partial pressure of each component in the atmosphere.
A quadrupole mass analyzer 137 and the like are attached. Since it is practically difficult to directly measure the pressure inside the envelope of the image display device 131, the pressure inside the vacuum chamber 133 is measured and controlled as processing conditions.

The vacuum chamber 133 is further connected to a gas introduction line 138 for introducing a necessary gas to control the atmosphere. An introduction substance source 140 is connected to the other end of the gas introduction line 138. The substance to be introduced is stored in an ampoule or a cylinder. In the middle of the gas introduction line, there is provided an introduction control means 139 for controlling the rate at which the introduced substance is introduced. As a specific example of the introduction amount control means, a valve such as a slow leak valve capable of controlling a flow rate to be released, a mass flow controller, or the like can be used according to the type of the substance to be introduced.

With the apparatus shown in FIG. 9, the inside of the envelope 37 is evacuated and forming is performed.
0, the Y-directional wiring 23 is connected to the common electrode 141, and the elements 24 connected to one of the X-directional wirings 22 are connected.
Then, a voltage pulse can be simultaneously applied by the power supply 142 to perform forming. Note that conditions such as the shape of the pulse and the determination of the end of the processing may be selected according to the method described above for the forming of the individual elements. In addition, by sequentially applying (scrolling) a pulse with a phase shifted to a plurality of X-direction wirings, it is possible to form elements connected to the plurality of X-direction wirings collectively. In the figure, reference numeral 143 denotes a current measuring resistor, and 144 denotes a current measuring oscilloscope.

After the forming is completed, an activation step is performed.
After exhausting sufficiently, the organic substance is introduced into the envelope 37 from the gas introduction line 138. Alternatively, as described in the method of activating individual exhaust, first, exhaust may be performed by an oil diffusion pump or a rotary pump, and thereby, an organic substance remaining in a vacuum atmosphere may be used. In addition, a substance other than the organic substance may be introduced as necessary.
By applying a voltage to each electron-emitting device in an atmosphere containing an organic substance formed in this way, carbon or a carbon compound, or a mixture of both, is deposited on the electron-emitting portion, and the electron emission amount is reduced. The movement to the stick is similar to that of the individual element. At this time, the voltage may be applied by applying the same voltage pulse to the elements 24 connected to one direction wiring by the same connection as in the above-described forming.

After the end of the activation process, it is preferable to carry out the stabilization process as in the case of the individual elements.
While the envelope 37 is heated and maintained at 80 to 250 ° C., the exhaust is exhausted through an exhaust pipe 132 by an exhaust device 135 that does not use oil, such as an ion pump and a sorption pump, to obtain an atmosphere containing a sufficiently small amount of organic substances. . Thereafter, the exhaust pipe is heated with a burner, melted, and sealed.

Note that a getter process can be performed to maintain the pressure after the envelope 37 is sealed. This is to heat a getter disposed at a predetermined position (not shown) in the envelope by heating using resistance heating or high-frequency heating immediately before or after sealing the envelope. This is a process for forming a deposited film. The getter usually contains Ba or the like as a main component, and maintains the atmosphere in the envelope by the adsorption action of the deposited film.

Next, an example of the configuration of a drive circuit for performing television display based on NTSC television signals on a display panel configured using electron sources in a simple matrix arrangement will be described with reference to FIG. I do. In FIG. 11, reference numeral 101 denotes an image display panel, 102 denotes a scanning circuit,
103 is a control circuit, and 104 is a shift register. Reference numeral 105 denotes a line memory, 106 denotes a synchronization signal separation circuit, 107 denotes a modulation signal generator, and Vx and Va denote DC voltage sources.

The display panel 101 has terminals Dox1 to Dox
xm, terminals Doy1 to Doyn, and a high voltage terminal Hv are connected to an external electric circuit. These terminals D
In ox1 to Doxm, electron sources provided in the display panel, that is, a group of surface conduction electron-emitting devices arranged in a matrix of M rows and N columns are sequentially driven one row (N element) at a time. Scan signal is applied.

The terminals Doy1 to Doyn are connected to one row of the surface conduction electron-emitting devices selected by the scanning signal.
A modulation signal for controlling each output electron beam is applied. The high-voltage terminal Hv is supplied with a DC voltage of, for example, 10 kV from a DC voltage source Va, which is sufficient to excite the phosphor into an electron beam emitted from the surface conduction electron-emitting device. It is an accelerating voltage for applying energy.

Next, the scanning circuit 102 will be described. The circuit includes m switching elements (schematically indicated by S1 to Sm in the figure). Each switching element is connected to the output voltage of the DC voltage source Vx or 0
One of V (ground level) is selected, and is electrically connected to the terminals Dox1 to Doxm of the display panel 101. Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 103, and can be configured by combining switching elements such as FETs, for example.

The DC voltage source Vx is, in this case,
Based on the characteristics (electron emission threshold voltage) of the surface conduction electron-emitting device, a constant voltage is output so that the driving voltage applied to the unscanned device is equal to or lower than the electron emission threshold voltage. Is set.

The control circuit 103 has a function of matching the operation of each unit so that appropriate display is performed based on an image signal input from the outside. The control circuit 103 controls the synchronization signal Tsync sent from the synchronization signal separation circuit 106.
, Tscan, Tsft, and Tmry control signals are generated for each unit.

The synchronizing signal separating circuit 106 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and uses a general frequency separating (filter) circuit or the like. Can be configured. The synchronizing signal separated by the synchronizing signal separating circuit 106 includes a vertical synchronizing signal and a horizontal synchronizing signal. Here, for the sake of explanation, it is illustrated as a Tsync signal. The luminance signal component of the image separated from the television signal is referred to as a DATA signal for convenience. This DATA signal is input to the shift register 104.

The shift register 104 is for serial-to-parallel conversion of a DATA signal input serially in time series for each line of an image.
It operates based on the control signal Tsft sent from the control register 03 (that is, it can be said that the control signal Tsft is a shift clock of the shift register 104). The data for one line of the image that has been subjected to the serial / parallel conversion (corresponding to drive data for N electron-emitting devices) is output from the shift register 104 as N parallel signals Id1 to Idn.

The line memory 105 is a storage device for storing data for one line of an image for a required time only, and stores the contents of Id1 to Idn as appropriate according to a control signal Tmry sent from the control circuit 103. . The stored contents are output as I'd1 to I'dn and input to the modulation signal generator 107.

The modulation signal generator 107 outputs the image data I'd
1 to I′dn are signal sources for appropriately driving and modulating each of the surface conduction electron-emitting devices in accordance with each of the surface conduction electron-emitting devices. Applied to the electron-emitting device.

As described above, the electron-emitting device to which the present invention is applied has the following basic characteristics with respect to the emission current Ie. That is, a clear threshold voltage V is required for electron emission.
and electron emission occurs only when a voltage equal to or higher than Vth is applied. For a voltage equal to or higher than the electron emission threshold, the emission current also changes according to the change in the voltage applied to the device. From this, when a pulse-like voltage is applied to the element, for example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur, but when a voltage higher than the electron emission threshold is applied, the electron beam is not emitted. Is output. At that time, the intensity of the output electron beam can be controlled by changing the peak value Vm of the pulse. Further, by changing the pulse width Pw, it is possible to control the total amount of charges of the output electron beam.

Therefore, as a method for modulating the electron-emitting device in accordance with the input signal, a voltage modulation method, a pulse width modulation method, or the like can be adopted. When implementing the voltage modulation method, a circuit of a voltage modulation method that generates a voltage pulse of a fixed length and appropriately modulates the peak value of the pulse according to input data is used as the modulation signal generator 107. Can be used.

In implementing the pulse width modulation method, the modulation signal generator 107 generates a voltage pulse having a constant peak value and modulates the width of the voltage pulse appropriately according to input data. A pulse width modulation type circuit can be used.

The shift register 104 and the line memory 10
5 can be a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed. When the digital signal type is used, the output signal DATA of the synchronization signal separation circuit 106 needs to be converted into a digital signal.
A converter may be provided. In this connection, the circuit used for the modulation signal generator 107 differs slightly depending on whether the output signal of the line memory 105 is a digital signal or an analog signal. That is, in the case of the voltage modulation method using a digital signal, the modulation signal generator 107 includes, for example,
A D / A conversion circuit is used, and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation method, the modulation signal generator 1
In 07, for example, a high-speed oscillator, a counter (counter) for counting the number of waves output from the oscillator, and a circuit combining a comparator (comparator) for comparing the output value of the counter with the output value of the memory are provided. Used. If necessary, an amplifier for amplifying the voltage of the pulse-width-modulated signal output from the comparator to the drive voltage of the surface-conduction electron-emitting device can be added.

In the case of the voltage modulation method using an analog signal, for example, an amplification circuit using an operational amplifier or the like can be used as the modulation signal generator 107, and a level shift circuit or the like can be added as necessary. . In the case of the pulse width modulation method, for example, a voltage-controlled oscillation circuit (VO
C) can be adopted, and if necessary, an amplifier for amplifying the voltage up to the driving voltage of the surface conduction electron-emitting device can be added.

In the image display apparatus to which the present invention is applied, which can take such a configuration, by applying a voltage to each of the electron-emitting devices via the terminals Dox1 to Doxm and Doy1 to Doyn outside the container, the electron-emitting device can emit electrons. Occurs. In addition, via a high voltage terminal Hv, a metal back or
A high voltage is applied to a transparent electrode (not shown) to accelerate the electron beam. The accelerated electrons collide with the fluorescent film, thereby emitting light and forming an image.

The configuration of the image forming apparatus described here is an example of the image forming apparatus according to the present invention, and various modifications are possible based on the technical idea of the present invention. Although the NTSC system has been described as the input signal, the input signal is not limited to this, and PAL, SEC
In addition to the AM system, a TV signal composed of a larger number of scanning lines (for example, a high-quality T
V) system can also be adopted.

FIG. 12A shows a schematic configuration and an electron beam corresponding to one pixel of an image forming apparatus as shown in FIG. 7 using an electron source in which a plurality of surface conduction electron-emitting devices are arranged in a matrix. Shows the flying state of. Here, reference numeral 75 denotes a high-potential-side device electrode, 76 denotes a low-potential-side device electrode, and 78 denotes a bright spot. FIG. 12B is an enlarged schematic view of the luminescent spot 78 of the phosphor observed by the present inventors in the device as shown in FIG.

As shown in FIG. 12A, the entire luminescent spot of the phosphor is in the direction of applying voltage to the device electrode (X direction in the figure) and in the direction perpendicular to it (Y direction). It was confirmed that it had spread. The reason why such a bright spot is formed, that is, the reason why the electron beam reaches the image forming member with a certain spread, is not clearly understood because the electron emission mechanism of the surface conduction electron-emitting device has not been completely elucidated. Although it cannot be explained, the present inventors believe that electrons having an initial velocity are emitted so as to be scattered in all directions from many experiments. Also, of the electrons emitted in all directions, the electrons emitted in the direction of the high-potential element electrode (in the figure, the X plus direction) reach the tip of the luminescent spot, and are directed in the direction of the low-potential element electrode (in the figure) , X
It is estimated that the amount of electrons emitted in the negative direction) is very small.

Further, according to the experiment of the present inventors, FIG.
In (a) and (b), it was found that the luminescent spot 78 was displaced from vertically above the electron-emitting portion 74 in the X-plus direction, that is, toward the high-potential-side device electrode 75. The reason for this is that the potential distribution in the space above the surface conduction electron-emitting device is such that the equipotential surface is not parallel to the surface of the image forming member 86 near the electron-emitting portion 74 as shown in FIG. The emitted electrons are accelerated by the acceleration voltage Va, and not only fly in the Z direction in the figure, but also
The present inventors believe that acceleration is also performed in five directions.
That is, it is considered that it is inevitable that electrons are subjected to a deflecting action immediately after they are emitted due to the applied voltage Vf necessary for emitting electrons.

The shape and size of the luminescent spot 78 and the electron emitting portion 74
From the examination of the value of the positional deviation in the X direction from above vertically, the amount of deviation (ΔX1 in (b) of FIG.
The amount of shift to the bright spot tail (ΔX2 in FIG. 12B),
Also, it can be understood that the size (ΔY) of the electron beam spot in the Y direction on the image forming member surface can be represented by using Va, Vf, and H as parameters (Japanese Patent Laid-Open No. 6-342636).
Reference).

Further, as a result of measuring the bright spot distribution within the bright spots, it was found that the amount of electrons reaching the face plate had the distribution shown in FIG. That is, in FIG.
It was required that 50% or more of the emitted electrons were concentrated on the luminescent spot 79. Vf is 10 to 20 V, Va is 1 kV to 10 k
V, the distance H between the face plate and the electron source substrate is 2 mm
In the range of ８8 mm, the coordinate ΔX of the luminance center 79 of this luminescent spot could be expressed by the following equation. ΔX = K1 × H × √ (Vf / Va) + K2 where K1 and K2 are constants, and K1 is approximately 2, K2
Is almost zero.

Vf, Va, and H are appropriately selected so that the coordinate ΔX of the luminance center of the base point thus obtained does not coincide with the normal direction of the insulating surface of the electron source substrate. Alternatively, by forming the electron source substrate, an image forming apparatus can be obtained in which the image is not disturbed or the elements are not deteriorated by the discharge.

[0097]

The present invention will be specifically described below with reference to examples. This embodiment is an example of an image forming apparatus in which many surface conduction electron-emitting devices are arranged in a simple matrix. First,
FIG. 15 shows a partial plan view of the electron source. Here, reference numeral 41
Denotes a substrate, 42 denotes an X-direction wiring (also referred to as a lower wiring) corresponding to Doxm in FIG. 7, 43 denotes a Y-direction wiring (also referred to as an upper wiring) corresponding to Doyn in FIG. 7, 44 denotes a thin film including an electron emitting portion, 45 and 46 are device electrodes, and 47 is an interlayer insulating layer.

Next, the manufacturing method will be described with reference to FIGS.
, And will be specifically described in the order of the steps.

[Step-a] The glass substrate 41 is washed. The substrate used was blue plate glass.

[Step-b] The device electrodes 45 and 46 are formed. A thick film printing method was used as a film forming method. The thick film paste material used here is MOD paste (D
U-2110, manufactured by Noritake Co., Ltd.), and the metal component is gold. The printing method is a screen printing method.
After printing, drying is performed at 110 ° C. for 20 minutes, and then main firing is performed. The firing temperature is 580 ° C. and the peak retention time is about 8 minutes. The film thickness after printing and baking was 0.3 μm.
The distance between the device electrodes was 50 μm.

[Step-c] Next, the Y-direction wiring 43 is formed. Thick film screen printing was used. The paste material is Noritake Co., Ltd. product (NP-4028A), and the metal component is silver. The firing is the same as in [Step-b]. The film thickness after printing and baking was 10 μm. In addition,
The Y-direction wiring is connected to one side of the element electrode 45.

[Step-d] Next, an interlayer insulating layer 47 is formed. Thick film screen printing was used. The paste material used was a mixture of PbO as a main component and a glass binder. The firing is the same as in [Step-b]. The film thickness after printing and baking was 30 μm. In addition,
The configuration is such that the X-direction wiring and the element electrode 46 can be connected.

[Step-e] Next, the X-direction wiring 42 is
It is formed in the same procedure as the Y-direction wiring 43. The film thickness after printing and baking was 10 μm. Further, a part of the X-direction wiring 42 is connected to the element electrode 46.

[Step-f] Next, a conductive thin film 44 is formed. An organic palladium-containing solution was applied so as to have a width of 80 μm by using a bubble jet type inkjet ejecting apparatus. A heat treatment was performed at 300 ° C. for 10 minutes to obtain a fine particle film composed of fine palladium oxide particles.

Through the above steps, X on the insulating substrate 41
The directional wiring 42, the interlayer insulating layer 47, the Y-directional wiring 43, the device electrodes 45 and 46, and the thin film 44 for forming the electron emission portion were formed. The shape of the device electrodes 45 and 46 and the dimensions of each member are shown in FIG.
5 is shown.

Next, an electron source and a display device were constructed using the electron source substrate prepared as described above. This will be described with reference to FIGS. That is, after fixing the substrate 21 on which the element is formed as described above on the rear plate 31, the face plate 36 (the fluorescent film 34 and the metal back on the inner surface of the glass substrate 33) is placed above the distance H (4 mm) of the substrate 21. 35 is formed via the support frame 32, frit glass is applied to the joint between the face plate 36, the support frame 32, and the rear plate 31, and baked at 400 ° C. for 10 minutes or more in the atmosphere. It was sealed. The fixing of the substrate 21 to the rear plate 31 was also performed with frit glass. In this embodiment, 24 in FIG.
Are the electron-emitting devices before the formation of the electron-emitting portion;
Reference numeral 3 denotes element wirings in the X and Y directions, respectively.

The fluorescent material of the fluorescent film 24 adopts a stripe shape (see FIG. 8). First, a black stripe 38 is formed.
4 was created. As a material for the black stripe, a material mainly containing graphite, which is commonly used, was used.
A slurry method was used as a method of applying the phosphor on the glass substrate 33. A metal back 35 is usually provided on the inner surface side of the fluorescent film 34.
After the formation of the fluorescent film, a smoothing treatment (usually called filming) of the inner surface of the fluorescent film is performed.
1 was prepared by vacuum evaporation.

In the face plate 36, a transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 34 in order to further increase the conductivity of the fluorescent film 34, but in this embodiment, a metal back is provided. Alone, sufficient conductivity was obtained, and was omitted. In addition, when performing the above-described sealing, sufficient alignment was performed so that the phosphors of each color and the electron-emitting devices had to correspond to each other.

The atmosphere in the glass container completed as described above is exhausted by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, a terminal Dox outside the container.
A voltage was applied between the electrodes 45 and 46 of the electron-emitting device 24 through 1 to Doxm and Doy1 to Doyn to form the electron-emitting portion forming thin film 24. FIG. 3 shows a voltage waveform of the forming process.

Here, T1 was set to 1 msec and T2 was set to 10 msec, and the test was performed in a vacuum atmosphere of about 1 × 10 ⁻⁵ torr.
The electron-emitting portion thus prepared was in a state in which fine particles mainly composed of palladium element were dispersed and arranged, and the average particle diameter of the fine particles was 3 nm. Next, the same rectangular wave as the forming, a wave height of 7 V and a degree of vacuum of 2 × 10 ⁻⁵ to
At a degree of vacuum of rr, a high resistance activation process was performed while measuring the device current If and the emission current Ie.

After performing such forming and activation processes to form an electron-emitting portion and to form an electron-emitting device,
Evacuation was performed to a degree of vacuum of about 10 ⁻⁶ torr, and an exhaust pipe (not shown) was heated and welded with a gas burner to seal the envelope. Finally, gettering was performed by a high-frequency heating method in order to maintain the degree of vacuum after sealing.

In the image display device of the present invention completed as described above, each of the electron-emitting devices has a terminal Dox1 outside the container.
To Doxm and Doy1 to Doyn, respectively, to apply a voltage Vf, thereby outputting a scanning signal and a modulation signal by a signal generation means (not shown) to emit electrons, and a metal back 35 through a high voltage terminal Hv. High voltage V
a, the electron beam is accelerated to collide with the fluorescent film 34 to excite and emit light.
A bright spot was formed on the top and the image was displayed.

The device current If and the emission current Ie are both shown by solid lines in FIG. Further, at this time, the emission current was able to correspond to the luminance of 100 fL to 150 fL required for the television.

In the present embodiment, the center coordinate ΔX of the above-mentioned bright spot can be expressed by the following equation. ΔX = K1 × H × √ (Vf / Va) + K2 where K1 = 2.0 and K2 = −6.25e−5.

(Embodiment 1) Next, a first embodiment of the present invention will be specifically described. This embodiment is an example of preventing the deterioration of the quality of the displayed image and the deterioration of the element due to discharge by appropriately selecting Va. In the above configuration, the image forming apparatus was configured with H = 4 mm. The voltage Vf is applied between the element electrodes 45 and 46 by the element driving power supply 81.
When = 10 V was applied, electrons were emitted from the electron emission section 44. Metal back 3 from power supply 82 for electron beam acceleration
When the acceleration voltage Va is applied to the phosphor 34 through 5,
The electrons are accelerated and collide with the phosphor 34 to emit light, thereby forming a bright spot on the face plate 33.

In the electron source substrate of this embodiment, the direction from the electron emission portion to the high potential side electrode (X plus direction) is 175 to 175.
The insulating surface is exposed at a position of 225 μm. And H
= 4 mm and Vf = 10 V, if Va is 8 kV or more, the luminance center of the luminescent spot is 220 μm or less according to the above equation, and it is located in the normal direction of the insulating surface. Therefore, in this embodiment, Va is used at 8 kV.

By using under the above conditions, a stable luminescent spot was formed and a high quality image was obtained. But,
When Va was used at 8 kV or more, the shape of the luminescent spot changed, the formed image became unstable, and deterioration of the element due to discharge was observed (see FIG. 17A). At this time, the luminance required for the television is 100 fL to 15 fL.
The emission current was able to handle 0 fL.

(Embodiment 2) In the second embodiment of the present invention, by appropriately selecting Vf, even at a higher Va, deterioration of display image quality and deterioration of the element due to discharge can be prevented. This is a case where a high-brightness image forming apparatus is obtained.

Here, in the configuration similar to that of the first embodiment, when Va is 10 kV, the deviation of the luminance center of the bright spot is 19
It is calculated to be 0 μm. On the other hand, the insulating surface is exposed at a position of 75 to 125 μm in the X minus direction on the electron source substrate. Therefore, if an image is formed at Vf = 10 V, it is considered that a stable bright spot is formed at Va of 10 kV.

By using the above conditions, 10 k
A stable bright spot was formed at V, and a high-quality image was obtained. Further, when the luminance of the obtained image is 8 kV,
It was 160 fL, but by making it 10 kV, 2
It was 70 fL (see FIG. 17B).

(Embodiment 3) In this embodiment, based on the results of Embodiments 1 and 2, when Va is 10 kV or less, the luminance center of the bright spot is always located in the normal direction of the insulating surface of the electron source substrate. Not designed. That is, when Va is 10 kV or less, the luminance center of the luminescent spot is formed at a position of 190 μm or more. Therefore, the direction from the electron-emitting portion to the high-potential-side electrode is set to Y
In the plus direction, the brightness center of the bright spot is X
It will be located in the direction normal to the direction wiring. Here, the electron source substrate having the configuration of FIG. 18 was formed in the same manner as in Example 1.

As a result of forming an image in the same manner as in Example 1, when Va was 10 kV or less, a stable bright spot was always formed (see FIG. 19).

[0123]

As described above, the present invention relates to an image forming apparatus using a surface conduction electron-emitting device.
By appropriately determining Va, Vf, H or the configuration of the electron source substrate, the trajectory of the electron beam could be made extremely stable.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one example of a surface conduction electron-emitting device of the present invention.

FIG. 2 is a schematic view showing one example of a method for manufacturing a surface conduction electron-emitting device according to the present invention.

FIG. 3 is a schematic diagram showing an example of a voltage waveform in an energization forming process that can be employed in manufacturing the surface conduction electron-emitting device.

FIG. 4 is a graph showing an example of the relationship between the emission current Ie, the device current If, and the device voltage Vf for the surface conduction electron-emitting device.

FIG. 5 is a schematic diagram illustrating an example of a vacuum processing apparatus having a measurement evaluation function.

FIG. 6 is a schematic diagram showing an example of an electron source having a simple matrix arrangement to which the present invention is applied.

FIG. 7 is a schematic diagram illustrating an example of a display panel of an image forming apparatus to which the present invention has been applied.

FIG. 8 is a schematic view showing an example of the fluorescent film.

FIG. 9 is a schematic view of a vacuum evacuation apparatus for performing a forming and activating process of the image display device of the present invention.

FIG. 10 is a schematic diagram showing a connection method for forming and activating processing steps of the image forming apparatus of the present invention.

FIG. 11 is a block diagram showing an example of a drive circuit for performing display in accordance with an NTSC television signal as the image forming apparatus of the present invention.

FIG. 12 is a perspective view showing a configuration of one pixel of the image forming apparatus of the present invention and a diagram showing a bright spot shape observed by a surface conduction electron-emitting device.

FIG. 13 is an equipotential diagram for explaining the trajectory of an electron beam of an image display device using a surface conduction electron-emitting device.

FIG. 14 is a diagram showing a distribution of the charge amount of a bright spot observed in the surface conduction electron-emitting device.

FIG. 15 is a schematic view showing an example of an electron source having a simple matrix arrangement to which the present invention is applied.

FIG. 16 is a diagram illustrating a manufacturing process of the electron source substrate according to the embodiment of the present invention.

FIG. 17 is a diagram for explaining an embodiment of the present invention.

FIG. 18 is a diagram for explaining the embodiment.

FIG. 19 is a view for explaining characteristics of the surface conduction electron-emitting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2, 3 Element electrode 4 Conductive thin film 5 Electron emission part 21 Electron source substrate 22 X direction wiring 23 Y direction wiring 24 Surface conduction type electron emitting element 31 Rear plate 32 Support frame 33 Glass substrate 34 Fluorescent film 35 Metal back 36 Face plate 37 envelope 38 black conductive material 39 phosphor 41 electron source substrate 42 X-direction wiring 43 Y-direction wiring 44 surface conduction electron-emitting device 45 device electrode 46 device electrode 47 interlayer insulating layer 50, 52 ammeter 51 electron emission Power supply 53 for applying device voltage Vf to the device 53 High-voltage power supply for applying voltage to anode electrode # 54 54 Anode electrode for capturing emission current Ie 55 Ammeter 56 Vacuum device 57 Exhaust pump 71 Electron source substrate 74 Surface conduction electron-emitting device 75 High-potential-side device electrode 76 Low-potential-side device electrode 78 Bright point 79 Main component of bright point 81 Power supply for applying element voltage Vf to electron-emitting device 82 Voltage power supply for applying voltage to anode electrode 86 Face plate 93 Glass substrate 101 Display panel 102 Scanning circuit 103 Control circuit 104 Shift register 105 Line memory 106 Synchronous signal separation circuit 107 Modulation signal generator 131 Image display device 132 Exhaust pipe 133 Vacuum chamber 134 Gate valve 135 Exhaust device 136 Pressure gauge 137 Quadrupole mass analyzer 138 Gas introduction line 139 Introducing amount control means 140 Source substance 141 Common electrode 142 Power supply 143 Resistance for current measurement 144 Oscilloscope Vx and Va DC voltage source

Continued on front page F term (reference) 5C031 DD09 DD17 5C036 EE02 EE09 EF01 EF06 EF09 EG12 EG24 EG45 EG50 EH01 EH02 5C058 AA11 AB01 BA01 BA06 BB01 BB20 5C080 AA08 BB05 CC03 DD05 FF10 GG08 KK02

Claims (1)

[Claims] 1. An electron source substrate having a plurality of surface conduction electron-emitting devices provided on a substrate, and a face plate having opposing phosphor targets receiving irradiation of electron beams from the surface conduction electron-emitting devices. An image forming apparatus comprising: an electron-emitting device, wherein a luminance center of a luminescent spot due to irradiation of an electron beam on the phosphor target is not located in a normal direction of an insulating surface on the electronic substrate. Image forming apparatus used.