JP2000243236A - Electron emission element, electron source substrate and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize superior electron emission characteristics and high brightness for a long time by comprising a pair of element electrodes formed on a glass base facing opposite to each another, and a conductive thin film connected to the element electrodes and including a clearance portion, and using the electron conductive glass as the glass base. SOLUTION: A surface conduction-type electron emission element comprises a base 1, element electrodes 2, 3, a conductive thin film 4 and a clearance portion (electron emission portion) 5. As the base 1, an electron conductive glass base is used, its surface resistance is preferably set equal to or larger than 1×108 Ω/(square), equal to or smaller than 1×1011 Ω/(square), and the electron conductivity of the electron conductive glass is set equal to or larger than 1×10-9 S/cm and equal to or smaller than 1×10-6 S/cm. Relative to the electron emission characteristics of the element, the elemental current is reduced as much as possible, and sufficient discharging effect can be obtained. The carriers contributing to conduction of the electron conductive glass are electrons or positive holes, and that of less movement of ions, that is, one having the lowest ion conductivity is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device, an electron source substrate, and an image forming apparatus such as a display device to which the electron-emitting device is applied, and more particularly, to a surface-conduction type electron-emitting device having a novel structure and using the same. The present invention relates to an electron source substrate and an image forming apparatus such as a display device as an application thereof.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a thermionic electron source and a cold cathode electron source, are known. The cold cathode electron source includes a field emission type (hereinafter abbreviated as FE type), a metal / insulating layer / metal type (hereinafter abbreviated as MIM type), and a surface conduction type electron emission element.

As an example of the FE type, W. P. Dyke &
W. W. Dolan, "Fielddemissio
n ", Advance in Electron Ph
ysics, 8, 89 (1956) or C.I. A. S
pindt, "PhysicalProperties
of thin-film field emiss
ion cathodes with mollybde
nium cones ", J. Appl. Phys.,
47, 5248 (1976).

As an example of the MIM type, C.I. A. Mea
d, “Operation of Tunnel-Em
issue Devices ", J. Apply. P.
hys. 32, 646 (1961) and the like are known.

As an example of the surface conduction electron-emitting device,
M. I. Elinson, RadioEng. Elec
Tron Phys. , 10, 1290, (1965)
Etc.

[0006] The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using an SnO ₂ thin film by Elinson et al. And a device using an Au thin film [G. Dimmer, Thin Solid Fil
ms, 9,317 (1972)], In 2 O 3 / SnO
₂ Thin film [M. Hartwell and
C. G. FIG. Fonsted, IEEE Trans. ED
Conf. , 519 (1975)], and those using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, p. 22 (1983)] and the like have been reported.

As a typical device configuration of these surface conduction electron-emitting devices, the above-mentioned M.D. FIG. 14 shows a device configuration of the Hartwell. In FIG. 1, reference numeral 1 denotes an insulating 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 a linear electron emitting portion 5 is formed by an energization process called forming, which will be described later. Note that the element electrode interval L in the figure is 0.5 to 1 m.
m and W ′ are set at 0.1 mm.

Conventionally, in these surface-conduction electron-emitting devices, the electron-emitting portion 5 is generally formed before the electron emission by performing an energization process called forming on the conductive thin film 4. That is, forming means applying a DC voltage or a very slowly increasing voltage, for example, about 1 V / min, to both ends of the conductive thin film 4 and energizing the conductive thin film 4 to locally destroy, deform or alter the conductive thin film, thereby increasing the electrical conductivity. This is to form the electron-emitting portion 5 in a resistance state. In the electron emitting portion 5, a crack is generated in a part of the conductive thin film 4, and electrons are emitted from the vicinity of the crack. The surface conduction type electron-emitting device that has been subjected to the forming treatment is configured to apply a voltage to the above-described conductive thin film 4 and cause a current to flow through the device, thereby causing the above-described electron-emitting portion 5 to emit electrons.

On the other hand, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-235255, there is a case where a process called an activation process is performed on an element after forming. The activation process is a process in which the device current If and the emission current Ie are significantly changed by this process.

[0010] The activation step can be performed by repeatedly applying a pulse voltage to the element in an atmosphere containing an organic substance, as in the forming process. With this process,
From the organic substance present in the atmosphere, carbon or a carbon compound is deposited on at least the electron-emitting portion of the device, and the device current If and the emission current Ie are significantly changed, so that better electron-emitting characteristics can be obtained.

An image forming apparatus can be constructed by using an electron source substrate on which a plurality of electron emitting elements as described above are formed and combining it with an image forming member made of a phosphor or the like.

[0012]

However, with the rapid progress of multimedia with the advancement of information in recent years, higher performance is required for image forming apparatuses such as displays. That is, the screen size of the display device is increased, the power consumption is reduced, the definition is increased, the image quality is increased, and the space is saved.

Therefore, in the above-described electron-emitting device, a highly efficient and stable electron-emitting characteristic can be maintained for a longer time so that an image forming apparatus to which the electron-emitting device is applied can provide a bright display image stably. Technology is desired. Here, the efficiency refers to a current (hereinafter, emission current) emitted in a vacuum with respect to a flowing current (hereinafter, referred to as element current If) when a voltage is applied to a pair of opposing element electrodes of the surface conduction electron-emitting device. Ie). That is, it is desirable that the device current If be as small as possible and the emission current Ie be as large as possible.

If high-efficiency electron emission characteristics can be stably controlled over a long period of time, for example, in an image forming apparatus using a phosphor as an image forming member, a low-power, bright, high-quality image forming apparatus, for example, a flat panel TV can be realized.

However, in such an image forming apparatus, since the brightness is obtained by accelerating the electrons emitted from the electron-emitting device and making the electrons incident on the phosphor, the inside of the image forming apparatus is vacuum and high. It is necessary to apply an acceleration voltage (referred to as Va). In the conventional electron-emitting device, since a glass substrate having high insulating properties is used as a base, a portion where the electron-emitting device or wiring for supplying voltage to the device is not formed, that is, the substrate is exposed. There was a case where the potential of the surface was unstable. As a result, it is described in Japanese Patent Application Laid-Open No. 02-072534 that the electrons emitted from the electron-emitting device become unstable.

The mechanism of this charging is unknown in detail, but it has been found that the higher the Va, the higher the potential on the exposed surface of the substrate. When the potential of the exposed surface of the base increases due to the charging, a discharge may occur from the surface of the base toward the electron-emitting device or the wiring, possibly damaging the device.

Therefore, in particular, when the device is driven by applying a large Va, not only the instability of electron emission due to charging but also the above-mentioned discharge may affect the life of the electron-emitting device. This has been one of the causes for deteriorating the quality of an image display device using an electron-emitting device.

The present invention has been made in view of the above problems, and provides a surface conduction electron-emitting device which realizes good electron emission characteristics and high luminance for a long time, and an electron source and an image forming apparatus using the same. .

[0019]

Means for Solving the Problems The present invention has been made by intensive studies in order to solve the above-mentioned problems, and has the following configuration. That is, the electron-emitting device of the present invention is an electron-emitting device having a pair of opposing element electrodes formed on a glass substrate, and a conductive thin film including a gap connected to the element electrodes. The glass substrate is an electron conductive glass. Preferably, the electron conductivity of the electron conductive glass is 1 × 10
^-9 S / cm or more and 1 × 10 ^-6 S / cm or less. Also,
It is desirable that the surface resistance of the electron conductive glass is 1 × 10 ⁸ Ω / □ or more and 1 × 10 ¹¹ Ω / □ or less. As the electron-emitting device, a surface conduction electron-emitting device can be preferably used. Further, the invention includes an electron source substrate and an image forming apparatus.

An electron source substrate according to the present invention is an electron source substrate which emits electrons in response to an input signal, wherein a plurality of the above-mentioned electron-emitting devices are arranged on a substrate. Are characterized by having a plurality of rows of electron-emitting devices having both ends connected to wirings, and further having modulation means. More preferably, a plurality of electron-emitting devices in which a pair of device electrodes of the electron-emitting device are connected to m bases in the X direction and n routes in the Y direction that are electrically insulated from each other on the base. It is characterized by having done.

The image forming apparatus of the present invention is an apparatus for forming an image based on an input signal, and is characterized by comprising at least an image forming member and the above-mentioned electron source.

[0022]

According to the electron-emitting device of the present invention, since the glass substrate is made of an electron-conductive glass, the surface is hardly charged, and even when a high Va is applied, the device is not discharged. Degradation can be suppressed, and as a result,
An electron-emitting device that can maintain stable electron-emitting characteristics for a long time can be realized.

According to the image forming apparatus of the present invention, a stable and good image can be formed for a long time.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described. First, the basic configuration of the surface conduction electron-emitting device according to the present invention will be described. 1A and 1B are a plan view and a cross-sectional view, respectively, showing the configuration of a basic surface conduction electron-emitting device according to the present invention. The basic configuration of the device according to the present invention will be described with reference to FIG. In FIG. 1, 1 is a base, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is a gap (electron emission portion). As the substrate 1, an electron conductive glass substrate can be used. In particular, it is desirable that the surface resistance be 1 × 10 ⁸ Ω / □ or more and 1 × 10 ¹¹ Ω / □ or less. this is,
As will be described later, in the electron emission characteristics of the device, the device current is preferably as small as possible, and therefore, the surface resistance is preferably 1 × 10 ⁸ Ω / □ or more. Further, in order to obtain a sufficient static elimination effect, the surface resistance is 1 × 10 ¹¹ / □.
It is desirable that:

In order to obtain the above-mentioned surface resistance, the electron conductivity of the above-mentioned electron conductive glass must be 1 × 10 ⁻⁹ S / cm.
At least 1 × 10 ⁻⁶ S / cm may be used. In addition, if only a static elimination effect is expected, an ion conductive glass can be used. However, in the ion conductive glass, ion segregation may occur, which may adversely affect the electron-emitting device.

The glass of the electron conductive glass in the present invention is a glass in which the carrier that contributes to conduction is an electron or a hole, and it is desirable that the movement of ions, that is, the ionic conductivity is as small as possible.

The allowable value of the ion conductive component is a range in which segregation of ions during driving of the electron-emitting device and an electromotive force generated by the segregation do not affect the electron-emitting characteristics. It suffices if it is 10 ¹² Ω / □ or more. As a means for easily calculating the ionic conduction component from the total conductivity, a step voltage having a steep rise (for example, a rise time of 10 nsec) can be applied to estimate the ionic conduction component from the time change of the current value. That is, a constant current (electron conduction component) that rises following the rise of the voltage, and then
In general, a current (electron conduction component + ion conduction component) that slowly rises in the order of several hundred μsec to several hours and reaches a maximum value is measured, and the current difference (ion conduction component) is divided by an applied voltage to obtain an ion. The resistance due to conduction can be determined.

Here, the current that has reached the maximum value may gradually decrease thereafter (ie, the displacement current). In such a case, however, in the present invention, the resistance determined by the peak value of the displacement current is used. It is desirable that the value be 1 × 10 ¹² Ω / □ or more.

In order to examine the ion-conductive component in more detail, it is also possible to use a known method for measuring the amount of precipitates due to the application of a DC voltage or for measuring the electromotive force after the application of a DC voltage. I can do it.

The material of the opposing device electrodes 2 and 3 may be any material as long as it has conductivity. For example, Ni, Cr, Au, Mo, W, Pt,
Metals or alloys such as Ti, Al, Cu, Pd and Pd, A
g, Au, RuO ₂ , Pd-Ag or other metal or metal oxide and printed conductor made of glass, etc., In ₂ O ₃ −
Examples thereof include transparent conductors such as SnO ₂ and semiconductor conductor materials such as polysilicon.

The element electrode interval L, the element electrode length W, the shape of the conductive thin film 4 and the like are appropriately designed according to the application form of the element, and for example, in a display device such as a television to be described later, it corresponds to the screen size. In particular, high-definition televisions require a small pixel size and high definition. Therefore, in order to obtain a sufficient luminance even when the size of the electron-emitting device is limited, it is designed so that a sufficient emission current is obtained.

The distance L between the device electrodes is from several tens nm to several hundred μm.
Yes, photolithography technology that is the basis of the method for manufacturing device electrodes, that is, the performance of the exposure machine and the etching method,
And is set by the voltage applied between the device electrodes,
Preferably, it is from several μm to several tens μm.

The element electrode length W and the film thickness d of the element electrodes 2 and 3 are determined by the resistance value of the electrode, the connection with the XY wiring described above,
It is appropriately designed in consideration of the arrangement problem of a large number of electron sources. Usually, the length W of the device electrode is several μm to several hundred μm.
And the film thickness d of the device electrodes 2 and 3 is from several nm to several μm.

As the conductive thin film 4, it is preferable to use a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of the step coverage for the device electrodes 2 and 3, the resistance value between the device electrodes 2 and 3, a forming condition described later, and the like.

Examples of materials satisfying the above conditions include Ni,
Preferably, a conductive material such as Au, PdO, Pd, or Pt is formed with a film thickness showing a resistance value of Rs (sheet resistance) of 1 × 10 ² to 1 × 10 ⁷ Ω / □. Note that Rs
Is a resistance R, R = Rs (l / w) measured in the length direction of a thin film having a thickness t, a width w, and a length l, and assuming that the resistivity is ρ, Rs = ρ / t. The film thickness showing the above-mentioned resistance value is in the range of about 5 nm to 50 nm, and in this film thickness range, the thin film of each material has the form of a fine particle film.

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 and arranged or in a state in which the fine particles are adjacent to each other or overlap each other (when some fine particles are formed). To form an island-like structure as a whole).

The particle size of the fine particles is in the range of several hundred pm to several hundred nm, preferably in the range of 1 nm to 20 nm.
Among the materials exemplified above, PdO can be easily formed into a thin film by sintering an organic Pd compound in air, and since it is a semiconductor, it has a relatively low electric conductivity and a film thickness for obtaining a resistance value Rs in the above range. Wide process margin,
Since the metal Pd can be easily reduced to reduce the film resistance after the formation of the gap, the material is suitable because the film resistance can be reduced. However, the effects of the present invention are not limited to PdO, and are not limited to the materials exemplified above.

The gap 5 is a high-resistance portion, such as a crack, formed on a part of the conductive thin film 4. The gap 5 is formed by a deposit containing carbon as a main component through an activation step described later. , A structure having a narrower gap. When an electric field is applied to the gap 5, electrons are emitted, a part of which is emitted as an element current If, and a part is emitted into a vacuum, which becomes an emission current Ie.

Various methods are conceivable as a method of manufacturing the electron-emitting device having the gap 5, and an example is shown in FIG. Hereinafter, the manufacturing method will be described in order with reference to FIGS. (1) After sufficiently washing the substrate 1 with a detergent, pure water and an organic solvent, an element electrode material is deposited by a vacuum deposition method, a sputtering method or the like, and then the element electrodes 2 and 3 are formed by a photolithography technique (FIG. 2). (A)).

(2) An organic metal solution is applied between the device electrode 2 and the device electrode 3 provided on the base 1 and dried to form an organic metal film. The organic metal solution is a solution of an organic metal compound containing a metal such as Pd, Ni, Au, or Pt as a main element. Thereafter, the organic metal film is heated and baked, and is patterned by lift-off, etching, or the like to form a conductive thin film 4 (FIG. 2).
(B)). Here, the description has been made with reference to the application method of the organic metal solution, but the present invention is not limited to this, and is formed by a vacuum evaporation method, a sputtering method, a CVD method, a dispersion coating method, a dipping method, a spinner method, an inkjet method, or the like. In some cases.

(3) Subsequently, when an energization process called forming is performed by applying a pulsed voltage or a rising voltage between the element electrodes 2 and 3 using a power supply (not shown), a portion of the conductive thin film 4 is formed. A gap 5 having a changed structure is formed (FIG. 2C). By this energization process, electrons are emitted from the vicinity of the gap 5 formed in the conductive thin film 4.

The electrical processing after the forming processing is performed in the measurement and evaluation apparatus shown in FIG. The measurement evaluation device will be described below. FIG. 3 is a schematic configuration diagram of a measurement evaluation device for measuring the electron emission characteristics of the device having the configuration shown in FIG. In FIG. 3, 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is a gap. Reference numeral 31 denotes a power supply for applying a device voltage Vf to the device, reference numeral 30 denotes an ammeter for measuring a device current If flowing through the conductive thin film 4 between the device electrodes 2 and 3, and reference numeral 34 denotes a device which is emitted from an electron emission portion of the device. An anode electrode for capturing the emission current Ie, 33 is a high-voltage power supply for applying a voltage to the anode electrode 34,
Reference numeral 2 denotes an ammeter for measuring an emission current Ie emitted from the electron emission portion 5 of the device.

In measuring the device current If and the emission current Ie of the electron-emitting device, the device electrode 2, the power source 31 and the ammeter 30 are connected, and the power source 3 is located above the electron-emitting device.
An anode electrode 34 connecting the 3 and the ammeter 32 is arranged. Further, the electron-emitting device and the anode electrode 34 are installed in a vacuum device, and the vacuum device is provided with devices necessary for a vacuum device such as an exhaust pump (not shown) and a vacuum gauge. Can be measured and evaluated. The exhaust pump does not use oil,
It is composed of a high vacuum system such as a magnetic levitation turbo pump and a dry pump, and an ultrahigh vacuum system including an ion pump. The entire vacuum device and the electron-emitting device can be heated by a heater (not shown).

The voltage of the anode electrode is set to 5 kV to 10 kV.
kV, the distance H between the anode electrode and the electron-emitting device is 2 mm
It was measured in a range of ８8 mm.

The forming process includes a case where a pulse having a constant pulse peak value is applied and a case where a voltage pulse is applied while increasing the pulse peak value.

First, FIG. 4A shows a voltage waveform in a case where a pulse having a constant pulse height is applied. In FIG. 4A, T1 and T2 are the pulse width and pulse interval of the voltage waveform, T1 is 1 sec to 10 msec, and T2 is 1
The time is set to 0 μsec to 100 msec, and the peak value of the triangular wave (the peak voltage at the time of forming) is appropriately selected.

Next, FIG. 4B shows a voltage waveform when a voltage pulse is applied while increasing the pulse peak value. In FIG. 4B, T1 and T2 are the pulse width and pulse interval of the voltage waveform, and T1 is 1 sec to 10 msec.
c, T2 is set to 10 μsec to 100 msec, and the peak value of the triangular wave (the peak voltage at the time of forming) is increased by, for example, about 0.1 V steps.

It should be noted that the forming process ends when the conductive thin film 2 is locally destroyed during the forming pulse.
A voltage that does not deform, for example, a pulse voltage of about 0.1 V is inserted, and the element current is measured to obtain a resistance value.
When the resistance was 1 MΩ or more, the forming was terminated.

In forming the gap described above, the forming process is performed by applying a triangular wave pulse between the electrodes of the device. However, the waveform applied between the electrodes of the device is not limited to a triangular wave. A desired waveform such as a rectangular wave may be used, and the peak value, pulse width, pulse interval, and the like are not limited to the values described above. Select an appropriate value according to.

(4) Next, an activation process is performed on the element for which the forming has been completed. The activation process is performed in an atmosphere containing an organic substance. This atmosphere uses an organic substance remaining in the atmosphere when the inside of the vacuum vessel is evacuated using, for example, an oil diffusion pump or a rotary pump. In addition, it can be obtained by introducing an appropriate organic substance into a vacuum once sufficiently evacuated by an ion pump or the like. The preferable pressure of the organic substance at this time differs depending on the above-described 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 aliphatic hydrocarbons of alkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, nitriles, phenols, carboxyls, sulfonic acids and the like. Organic acids and the like, specifically, methane, ethane, propane such as saturated hydrocarbon represented by C _n H _{2n +2} , ethylene, propylene represented by a composition formula such as C _n H _2n Unsaturated hydrocarbons, benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methylamine,
Ethylamine, phenol, benzonitrile, acetonitrile, formic acid, acetic acid, propionic acid and the like can be used. By this treatment, carbon is deposited on the element from the organic substance existing in the atmosphere, and the element current If and the emission current Ie change significantly.

The end of the activation step is determined as appropriate while measuring the device current If and / or the emission current Ie. The pulse width, pulse interval, pulse crest value, and the like can be set as appropriate.

(5) In the electron-emitting device thus manufactured,
Preferably, a stabilization step is performed. This step is a step of exhausting the organic substance in the vacuum vessel. The pressure in the vacuum vessel is preferably 1 to 3 × 10 ⁻⁷ Torr or less, and more preferably 1 to 3 × 10 ⁻⁷ Torr.
It is particularly preferably at most 10 × 10 ⁻⁸ Torr. When the inside of the vacuum vessel is 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 conditions at this time are 80 to
It is desirable to carry out the treatment at 350 ° C., preferably 200 ° C. or more for as long as possible. However, the condition is not particularly limited, and the treatment is carried out under conditions appropriately selected according to various conditions such as the size and shape of the vacuum vessel and the configuration of the electron-emitting device. .

The atmosphere at the time of driving after performing the stabilizing step is preferably the same as the atmosphere at the end of the stabilizing treatment, but is not limited to this. If the organic substance is sufficiently removed, Even if the pressure itself increases somewhat, it is possible to maintain sufficiently stable characteristics.

By adopting such a vacuum atmosphere, the deposition of new carbon or carbon compound can be suppressed.
As a result, the element current If and the emission current Ie are stabilized. The basic characteristics of the electron-emitting device manufactured by the above-described manufacturing method to which the present invention can be applied will be described with reference to FIGS. FIG. 5 shows a typical example of the emission current Ie, the device current If, and the device voltage Vf measured by the measurement evaluation device shown in FIG. In FIG. 5, since the emission current Ie is significantly smaller than the element current If, the emission current Ie is shown in arbitrary units, and each of them is a linear scale. As is clear from FIG. 5, the electron-emitting device has three properties with respect to the emission current Ie.

First, when an element voltage higher than a certain voltage (called a threshold voltage, Vth in FIG. 5) is applied to the present element, the emission current Ie sharply increases, while the threshold voltage Vt is increased.
Below h, the emission current Ie is hardly detected. That is, a clear threshold voltage Vth with respect to the emission current Ie
Is a non-linear element having

Second, since the emission current Ie depends on the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf.

Thirdly, the amount of the emitted charges captured by the anode electrode 34 depends on the time during which the device voltage Vf is applied. That is, the amount of charge captured by the anode electrode 34 can be controlled by the time during which the device voltage Vf is applied.

In the present invention, although the electron conductive glass is used as the substrate 1, its surface resistance is 1 × 1.
0 ⁸ Ω / □ for more and high, the current through the substrate surface,
This is because it is sufficiently smaller than the element current.

When the characteristics of the surface conduction electron-emitting device described above are used, the electron emission characteristics can be easily controlled according to an input signal. Further, since the electron-emitting device according to the present invention has stable and high-luminance electron emission characteristics for a long time, application to various fields can be expected.

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

For the arrangement of the elements on the substrate, for example,
A large number of electron-emitting devices are arranged in parallel, and both ends of each element are connected by wiring. A large number of electron-emitting device rows are arranged (referred to as a row direction). ), A control electrode (called a grid) installed in a space above the electron source to control and drive the electrons (called a ladder type), and n There is an array configuration in which the Y-directional wiring is disposed via an interlayer insulating layer, and the X-directional wiring and the Y-directional wiring are connected to a pair of device electrodes of the surface conduction electron-emitting device, respectively. Hereinafter, this is referred to as a simple matrix arrangement.

Next, the simple matrix arrangement will be described in detail. According to the characteristics of the above-mentioned three basic characteristics of the surface conduction electron-emitting device according to the present invention, the electrons emitted from the surface conduction electron-emitting device are above the threshold voltage.
It can be controlled by the peak value and the 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 the pulse-like voltage is appropriately applied to each of the devices, a surface conduction electron-emitting device is selected in accordance with an input signal. The amount of electron emission can be controlled.

Hereinafter, the structure of the electron source substrate formed based on this principle will be described with reference to FIG. Wiring 62, 6
Reference numeral 3 is for supplying power to a plurality of electron-emitting devices. The m X-direction wirings 63 are DX1, DX2,.
DXm, n Y direction wiring 62, DY1, DY2,...
DYn (m and n are both positive integers), and the material, film thickness, wiring width, and the like are designed such that a substantially uniform voltage is supplied to many electron-emitting devices. These m
Between the X-direction wirings 63 and the n-direction wirings 62,
An interlayer insulating layer 64 is provided and electrically separated to form a matrix wiring.

The shape, material, film thickness, and manufacturing method of the interlayer insulating layer 64 can be appropriately set so as to withstand the potential difference at the intersection of the wiring 62 and the wiring 63. However, like the wiring, a material that can be formed by a printing method is preferable. A thick glass layer obtained by printing a glass paste is used.

In the configuration shown in FIG. 6, that is, the configuration of the matrix arrangement, a scanning signal (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices arranged in the X direction is applied to the X-direction wiring 63. The Y-direction wiring 62 is connected to a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices arranged in the Y-direction in accordance with an input signal.

The driving voltage applied to each electron-emitting device is
It is supplied as a difference voltage between the scanning signal and the modulation signal applied to the element, and individual elements can be selected using a simple matrix wiring and can be independently driven.

On the other hand, in addition to the above, each of a large number of electron-emitting devices arranged in parallel is connected at both ends, and a large number of rows of electron-emitting devices are arranged. There is a ladder-like arrangement in which electrons from the electron-emitting device are controlled and driven by a control electrode arranged above,
The present invention is not particularly limited by these arrangements.

Next, an image forming apparatus for display and the like using the electron source substrate manufactured as described above will be described with reference to FIGS. 7 and 8. FIG. FIG. 7 is a basic configuration diagram of the image forming apparatus, and FIG. 8 is a fluorescent film.

In FIG. 7, reference numeral 71 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged; 72, a rear plate on which the electron source substrate 71 is fixed; 77, a fluorescent film 75 on the inner surface of a glass substrate 74;
And a face plate on which a metal back 76 and the like are formed. Reference numeral 73 denotes a support frame. The rear plate 72, the support frame 73, and the face plate 77 are coated with frit glass or the like, and are heated and fired in the air or in nitrogen to seal the envelope 79. Constitute. Here, it is preferable that the frit glass be used in accordance with the coefficient of thermal expansion of the substrate because peeling, deformation, cracking, and the like of the substrate hardly occur.

The envelope 79 is composed of the face plate 77, the support frame 73, and the rear plate 72 as described above, but the rear plate 72 is provided mainly for the purpose of reinforcing the strength of the substrate 71. If the substrate itself has sufficient strength, the separate rear plate 72 is unnecessary, and
1, a support frame 73 is directly sealed, and a face plate 77,
The envelope 79 may be constituted by the support frame 73 and the substrate 71.

On the other hand, by providing a support (not shown) called a spacer between the face plate 77 and the rear plate 72, an envelope 79 having sufficient strength against atmospheric pressure can be formed. .

FIG. 8 shows a fluorescent film. The fluorescent film 75 is composed of only a phosphor in the case of a monochrome, but is composed of a black conductive material 81 called a black stripe or a black matrix and a phosphor 82 depending on the arrangement of the phosphor in the case of a color fluorescent film. . The purpose of providing the black stripes and the black matrix is to make the mixed portions between the phosphors 82 of the three primary color phosphors necessary for the color display black so that the color mixture and the like become inconspicuous. In suppressing a decrease in contrast due to reflection of external light. The material of the black stripe is not limited to the commonly used material containing graphite as a main component, as long as it is conductive and has little light transmission and reflection.

The method of applying the fluorescent substance to the glass substrate 74 is not limited to monochrome or color, and a precipitation method, a printing method, or the like is used.

A metal back 76 is usually provided on the inner surface side of the fluorescent film 75. The purpose of the metal back is to improve the brightness by mirror-reflecting the light toward the inner surface side of the phosphor emission toward the face plate 77 side, to function as an electrode for applying an electron beam acceleration voltage, This is to protect the phosphor from damage due to collision of negative ions generated in the enclosure. The metal back can be produced by performing a smoothing process (usually called filming) on the inner surface of the phosphor film after producing the phosphor film, and then depositing Al by vacuum evaporation or the like.

The fluorescent film 7 is further provided on the face plate 77.
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 75 in order to increase the conductivity of the fluorescent film 75.

When the above-mentioned sealing is performed, in the case of color, the phosphors of each color must correspond to the electron-emitting devices, so that it is necessary to perform sufficient alignment.

The envelope 79 is connected to an exhaust pipe (not shown) to
After the degree of vacuum is set to about × 10 ⁻⁷ Torr, sealing is performed. Further, a getter process may be performed in order to maintain the degree of vacuum after sealing the envelope 79. This is because the getter disposed at a predetermined position (not shown) in the envelope 79 is heated by a heating method such as resistance heating or high-frequency heating immediately before or after sealing the envelope 79. ,
This is a process for forming a deposition film. The getter is usually composed mainly of Ba or the like.
A vacuum degree of × 10 ^-5 or 1 × 10 ^-7 Torr is maintained.

In the image display device of the present invention completed as described above, a voltage is applied to each electron-emitting device through external terminals Dox1 to Doxm, Doy1 to Doyn, thereby emitting electrons. An image is displayed by applying a high voltage of several kV or more to the metal back 76 or a transparent electrode (not shown), accelerating the electron beam, colliding with the fluorescent film 75, and exciting and emitting light.

The above-described configuration is a schematic configuration necessary for manufacturing a suitable image forming apparatus used for display and the like, and detailed portions such as materials of each member are limited to the above-described contents. Instead, it is appropriately selected so as to be suitable for the purpose of the image device.

[0081]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. [Embodiment 1] The basic structure of a surface conduction electron-emitting device according to this embodiment is the same as the plan view and cross-sectional view of FIGS.

The method for manufacturing the surface conduction electron-emitting device according to this embodiment is basically the same as that shown in FIG. Hereinafter, a basic configuration and a manufacturing method of the device according to the present embodiment will be described with reference to FIGS. Hereinafter, the description of the manufacturing method will be described in order with reference to FIGS. (Step-a) First, V ₂ O ₅ —P ₂ O ₅ —
BaO glass (electronic conductivity 10 ^-6 S / cm, surface resistance 1)
0 ⁸ Ω / □) A pattern to be a gap L between the device electrodes 2 and 3 and a desired device electrode is formed on the substrate 1 by using a photoresist (RD-2000N-41 manufactured by Hitachi Chemical Co., Ltd.), and is subjected to electron beam evaporation. , 5 nm thick Ti, 100 thickness
nm of Ni was sequentially deposited. The photoresist pattern was dissolved with an organic solvent, the Ni / Ti deposited film was lifted off, the element electrode interval L was set to 3 μm, and the element electrode width W was set to 300 μm.
The device electrodes 2 and 3 having m were formed.

(Step-b) A Cr film having a thickness of 100 nm is deposited by vacuum evaporation, patterned so as to have an opening corresponding to the shape of a conductive thin film described later, and then an organic palladium compound solution (ccp4230 Okuno Pharmaceutical Co., Ltd.) )
Co., Ltd.) was spin-coated with a spinner and baked at 300 ° C. for 12 minutes. The conductive thin film 4 formed of fine particles of Pd as the main element thus formed had a thickness of 10 nm and a sheet resistance Rs of 2 × 10 ⁴ Ω / □. Note that the fine particle film described here is a film in which a plurality of fine particles are aggregated as described above.

(Step-c) The Cr film and the baked conductive thin film 4 were etched with an acid etchant to form a conductive thin film 4 having a desired pattern. Through the above steps, the device electrodes 2 and 3 and the conductive thin film 4 were formed on the base 1.

[0085] Next (step -d), was placed in the measurement evaluation apparatus in Fig. 3, it is evacuated by a vacuum pump, after reaching the vacuum degree of 1 × 10 ^-8 Torr, applying the device voltage Vf to the device A voltage was applied between the device electrodes 2 and 3 of the device from a power supply 31 for performing a forming process. The voltage waveform of the forming process is that shown in FIG.

In FIG. 4B, T1 and T2 are the pulse width and pulse interval of the voltage waveform. In this embodiment, T1 is 1 ms.
ec and T2 are 10 msec, and the peak value of the rectangular wave is 0.
The voltage was raised in steps of 1 V, and a forming process was performed.
During the forming process, a resistance measuring pulse was simultaneously inserted between the forming pulses at a voltage of 0.1 V to measure the resistance. The forming process was terminated when the value measured by the resistance measurement pulse became about 1 MΩ or more, and at the same time, the application of the voltage to the element was terminated.

(Step-e) Subsequently, in order to perform the activation step, benzonitrile was introduced into the vacuum apparatus through a slow leak valve, and the pressure was maintained at 1.0 × 10 ⁻⁶ Torr. Next, the element subjected to the forming treatment was activated at a peak value of 14 V with the waveform shown in FIG. That is, a pulse voltage was applied between the device electrodes while measuring the device current If in the measurement and evaluation device. Since the If value was substantially saturated in about 30 minutes, the energization was stopped, the slow leak valve was closed, and the activation process was terminated.

(Step-f) Subsequently, a stabilizing step is performed. While the vacuum device and the electron-emitting device were heated by the heater and maintained at about 250 ° C., the evacuation of the vacuum device was continued. After 20 hours, the heating by the heater was stopped and the temperature was returned to room temperature, and the pressure in the vacuum apparatus was 5 × 10 ⁻¹⁰ Torr.
Degree reached.

Subsequently, the electron emission characteristics were measured using the measurement evaluation apparatus shown in FIG. Anode electrode 3
The distance H between 4 and the electron-emitting device was 4 mm, and a high-voltage power supply 33 applied a potential of 10 kV to the anode electrode 34. In this state, a rectangular pulse voltage having a peak value of 14 V is applied between the device electrodes 2 and 3 using the power supply 31 to thereby make the ammeter 3
The device current If and the emission current Ie of the device of this example and the device of the comparative example were measured by 0 and the ammeter 32, respectively.

During the measurement, when the potential of the exposed surface of the substrate 1 was measured with a surface voltmeter, no potential increase was observed.

The electron emission characteristics of the device of this embodiment are as follows: device current If = 4.0 mA, emission current Ie = 25.3 μA, electron emission efficiency η (= Ie / If) = 0.63%. Although driving was continued, discharge did not occur in particular, and good characteristics were maintained.

[Embodiment 2] This embodiment is an example of an image forming apparatus in which a large number of surface conduction electron-emitting devices are arranged in a simple matrix. FIG. 10 shows a part of the electron source substrate. FIG. 11 is a cross-sectional view taken along the line AA ′ in the figure. However, FIG. 10, FIG.
The same symbol in 1 indicates the same item. Here, 1 is a substrate, 63 is an X-direction wiring (also referred to as an upper wiring) corresponding to DXm in FIG. 6, 62 is a Y-direction wiring (also referred to as a lower wiring) corresponding to DYn in FIG. 3 is a device electrode, 5 is a gap, and 64 is an interlayer insulating layer.

Next, the manufacturing method will be specifically described with reference to FIG. (Step-a) Cleaned V ₂ O ₅ —P ₂ O ₅ —BaO glass (electronic conductivity 10 ⁻⁶ S / cm surface resistance 10 ⁸ Ω /
□) 5 nm thick Ti and 50 nm thick Pt are sequentially deposited on the body 1 by a sputtering method. Then, the device electrode 2
3 is formed of a photoresist, and Pt other than the pattern of the device electrodes 2 and 3 is formed by dry etching.
The / Ti deposited layer is removed, and finally the photoresist pattern is removed to form device electrodes 2 and 3 (FIG. 12A).

(Step-b) On the substrate 1 on which the device electrodes 2 and 3 are formed, a pattern of the wiring 62 is formed using an Ag paste by screen printing, dried, baked at 500 ° C., and made of Ag. Is formed (FIG. 12B).

(Step-c) Next, a pattern of the interlayer insulating layer 64 is formed by screen printing using a glass paste, dried, and baked at 500 ° C. In order to obtain sufficient insulating properties, printing, drying, and firing of the glass paste are repeated again to form an interlayer insulating layer 64 of a desired shape made of glass (FIG. 12C).

(Step-d) The pattern of the upper wiring 63 is formed by screen printing using an Ag paste so as to intersect with the lower wiring 62 at the portion where the interlayer insulating layer 64 is formed. To form an upper wiring 63 of a desired shape made of Ag (FIG. 13 (d)). Through the above steps, the device electrodes 2 and 3 are
Substrates connected in a matrix by 2, 63 can be formed.

(Step-e) Next, a conductive thin film 4 is formed so as to extend between the gaps between the device electrodes 2 and 3. The conductive thin film 4 is formed by applying an organic palladium solution to a desired position by an inkjet method, and performing a heating and baking treatment at 350 ° C. for 30 minutes. The conductive thin film 4 thus obtained is composed of fine particles mainly composed of PdO and has a thickness of about 10 n.
m (FIG. 13 (e)).

Through the above steps, the lower wiring 62,
The interlayer insulating layer 64, the upper wiring 63, the element electrode 23, and the conductive thin film 4 were formed, and an electron source substrate was manufactured. Hereinafter, an example in which an image forming apparatus is configured using the electron source substrate of this embodiment will be described with reference to FIGS. After fixing the electron source substrate 71 manufactured as described above on the rear plate 72, a face plate 77 (a fluorescent film 75 and a metal back 76 are formed on the inner surface of the glass substrate 74) 5 mm above the electron source substrate 71. Is arranged via a support frame 73, and frit glass is applied to the joint between the face plate 77, the support frame 73, and the rear plate 72.
Sealing was performed by firing at 00 ° C. for 30 minutes. Fluorescent film 75
In the case of monochrome, only the phosphor is used, but in this embodiment, the phosphor adopts a stripe shape, a black stripe is formed first, and each color phosphor is applied to the gap, thereby forming a phosphor film 75. did. As the material for the black stripe, a material mainly containing graphite, which is generally used, was used. A slurry method was used to apply the phosphor onto the glass substrate 74.

A metal back 76 is usually provided on the inner side of the fluorescent film 75. The metal back was manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film after the fluorescent film was manufactured, and then vacuum-depositing Al.

The face plate 77 is further provided with a fluorescent film 7.
In some cases, a transparent electrode (not shown) is provided on the outer surface side of the fluorescent film 75 in order to enhance the conductivity of the phosphor layer 5. However, in this embodiment, a sufficient conductivity is obtained with only the metal back, and thus is omitted. did.

When the above-mentioned sealing was performed, in the case of color, the phosphors of each color had to correspond to the electron-emitting devices, so that sufficient alignment was performed.

The atmosphere in the glass container completed as described above is evacuated by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the external terminals Dox1 to Doxm and Doy1 to Doyn. A voltage was applied to the device electrodes 2 and 3 through the process to form the conductive thin film 4. The voltage waveform of the forming process is shown in FIG.
Is the same as

In this embodiment, T1 is 1 msec, and T2 is 1
The process was performed at 0 msec in a vacuum atmosphere of about 1 × 10 ⁻⁵ Torr. Thereafter, the entire glass container was heated at 200 ° C. for 2 hours while evacuating with a vacuum pump. At this time, the conductive thin film 4 containing PdO as a main component was thermally reduced to become a film containing Pd as a main component.

Next, after the gas was continuously exhausted until the pressure in the panel reached the level of 10 ^-8 Torr, an organic substance was introduced into the panel from the exhaust pipe of the panel so that the total pressure became 110 ^-6 Torr. , Maintained. Outer container terminal Dox1 to Dox
m and between the device electrodes 23 through Doy1 to Doyn,
An activation process was performed by applying a pulse voltage having a peak value of 15 V. In this manner, the forming and the activating processes were performed to form the gaps 5 (FIG. 13F).

Next, the gas was evacuated to a pressure of about 10 ^-6 Torr, and an exhaust pipe (not shown) was heated with a gas burner to be welded to seal the envelope. Finally, in order to maintain the pressure after sealing, getter processing was performed by a high-frequency heating method.

In the image display device of the present invention completed as described above, each of the electron-emitting devices has an external terminal Dox1.
The scanning signal and the modulation signal are applied by signal generating means (not shown) through Doxm, Doy1 to Doyn, respectively, to emit electrons, and the high voltage terminal 78
, A high voltage of 10 kV is applied to the metal back 76 or the transparent electrode (not shown) to accelerate the electron beam,
The image was displayed by colliding with the fluorescent film 75 to excite and emit light.

The image display device of this example was able to display a good image stably for a long period of time with a luminance sufficiently satisfactory for a television.

[0108]

As described above, according to the present invention, since the electron conductive glass substrate is used as the base, a high Va is obtained.
, It is possible to provide an electron-emitting device that is less likely to be charged even when a voltage is applied, and that can extract a stable electron-emitting current for a long time.

Further, in an electron source substrate that emits electrons in response to an input signal, a plurality of the above-described electron-emitting devices are arranged on the substrate to constitute an electron source. It has a plurality of rows of electron-emitting devices, both ends of which are connected to a wiring, and further has an arrangement method having a modulating means, or a substrate having m X-direction wirings and n wirings electrically insulated from each other. The electron source substrate has a configuration in which a plurality of electron-emitting devices in which a pair of device electrodes of the electron-emitting device are connected to the Y-direction wiring are arranged. Can be provided for a long time.

In the image forming apparatus, since the image forming apparatus is composed of the image forming member and the electron source substrate and forms an image based on an input signal, the stability of electron emission characteristics and the life are improved. In the image forming apparatus using the image forming member as the image forming member, a high-quality image forming apparatus can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a basic surface conduction electron-emitting device according to the present invention.

FIG. 2 is a view for explaining a basic method of manufacturing a surface conduction electron-emitting device according to the present invention.

FIG. 3 is a diagram of a measurement and evaluation apparatus used for evaluating characteristics of the surface conduction electron-emitting device according to the present invention.

FIG. 4 is a diagram showing an example of a voltage waveform in a forming process according to the present invention.

FIG. 5 is a diagram showing a typical example of the relationship among the emission current, the device current, and the device voltage of the surface conduction electron-emitting device according to the present invention.

FIG. 6 is a diagram showing a configuration of an electron source substrate according to the present invention.

FIG. 7 is a diagram illustrating a basic configuration of an image forming apparatus according to the present invention.

FIG. 8 is a diagram illustrating a fluorescent film used in the image forming apparatus of FIG. 7;

FIG. 9 shows an activation pulse shape suitable for the present invention.

FIG. 10 is a diagram illustrating a part of a configuration of an electron source according to a second embodiment of the present invention.

11 is a sectional view taken along the line AA 'of FIG.

FIG. 12 is a diagram for explaining a manufacturing process of the electron source according to the second embodiment of the present invention.

FIG. 13 is a view illustrating a manufacturing process of the electron source according to the second embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a conventional surface conduction electron-emitting device.

[Explanation of symbols]

1: substrate, 2, 3: device electrode, 4: conductive thin film, 5: gap (electron emission portion), 30: current for measuring device current If flowing through conductive thin film between device electrodes 2, 3 3 in total
1: power supply for applying the device voltage Vf to the electron-emitting device, 32: emission current I emitted from the electron-emitting portion of the device
e: an ammeter for measuring e; 33: a high-voltage power supply for applying a voltage to the anode electrode 34; 34: an anode electrode;
62: Y direction wiring, 63: X direction wiring, 64: interlayer insulating layer, 71: electron source substrate, 72: rear plate, 73: support frame, 74: glass substrate, 75: fluorescent film, 76: metal back, 77 : Face plate, 78: high voltage terminal, 7
9: envelope, 81: black conductive material, 82: phosphor.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuya Miyazaki, 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Tomoko Maruyama 3-30-2 Shimomaruko, Ota-ku, Tokyo 5C036 EE03 EF01 EF06 EF08 EG01 EG02 EG12 EH08 EH21

Claims (8)

[Claims] 1. An electron-emitting device comprising: a pair of opposing device electrodes formed on a glass substrate; and a conductive thin film including a gap connected to the device electrodes, wherein the glass substrate is provided. Is an electron-emitting device, which is an electron-conductive glass. 2. An electron conductive glass having an electron conductivity of 1
2. The electron-emitting device according to claim 1, wherein the electron-emitting device has a ^{density of at} least ^10-9 S / cm and at most 1 ^10-6 S / cm. 3. The electron conductive glass has a surface resistance of 1 ×.
The electron-emitting device according to any one of claims 1 and 2, wherein the electron emission intensity is 10 ⁸ Ω / or more and 1 × 10 ¹¹ Ω / □ or less. 4. The electron-emitting device according to claim 1, wherein said electron-emitting device is a surface conduction electron-emitting device. 5. An electron source substrate for emitting electrons according to an input signal, wherein a plurality of the electron-emitting devices according to claim 1 are arranged on a substrate. Electron source substrate. 6. A method according to claim 1, wherein a plurality of said electron-emitting devices are arranged in parallel, a plurality of rows of electron-emitting devices having both ends of each device connected to said metal wiring, and further comprising modulation means. Item 6. An electron source substrate according to item 5. 7. A pair of device electrodes of said electron-emitting device are connected to m X-direction metal wires and n-Y metal wires electrically insulated from each other, and the electron-emitting devices are arranged in a matrix. The electron source substrate according to claim 6, wherein the electron source substrates are arranged. 8. An apparatus for forming an image based on an input signal, wherein the apparatus comprises at least an image forming member and the electron source substrate according to any one of claims 5 to 7. Forming equipment.