JP3302255B2 - Electron emitting element, electron source substrate, and method of manufacturing image forming apparatus - Google Patents

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 a method for manufacturing an image forming apparatus.

[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”), a surface conduction type electron emission element, and the like. As an example of the FE type, "WPPD
yke & W. W. Dolan, "Field emis
sion ”, Advance in Electron
Physics, 8, 89 (1956) "or" CA Spindt, "Physical Pro.
parties of thin-film field
de emission cathodes with
mollybdenium ", J. Appl. Phys.
s. , 47, 5248 (1976) ". Examples of the MIM type include “CAMead,“ Th
e Tunnel-emission amplifi
er ", J. Appl. Phys., 32, 646 (1
961)).

Examples of the surface conduction electron-emitting device include:
"MI Elinson, Radio Eng. El
electron Phys. , 1290 (1965) ". 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. Dittmer:“ Thin SolidFi
lms ", 9 317 (1972)"), In ₂ O ₃ /
By a SnO ₂ thin film (“M. Hartwell a
nd C.I. G. FIG. Fonstad: “IEEE Tran
s. ED Conf. ", 519 (1975)"), a carbon thin film ("Hisashi Araki et al .: Vacuum, 26th
Vol. 1, No. 22, p. 22 (1983) ").

A typical device configuration of these surface conduction electron-emitting devices is described in the above-mentioned M.S. FIG. 12 shows the device configuration of the Hartwell. 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 emitting portion 5 is formed by an energization process called energization forming described later.
In addition, the element electrode interval L in the figure is 0.5 mm to 1 mm,
W 'is set at 0.1 mm. Since the position and shape of the electron-emitting portion 5 are unknown, they are shown as schematic diagrams.

Conventionally, in these surface conduction electron-emitting devices, the electron-emitting portion 5 is generally formed by subjecting the conductive thin film 4 to an energization process called energization forming before performing electron emission. It is a target. The energization forming is to apply 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 to energize the conductive thin film 4 to locally destroy, deform or alter the conductive thin film 4. Electron emitting portion 5 in a resistance state
Is to form 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. In the surface conduction type electron-emitting device subjected to the energization forming process, a voltage is applied to the conductive thin film 4 and a current flows through the device to cause the electron-emitting portion 5 to emit electrons.

The above-mentioned surface conduction type emission element has an advantage that a large number of elements can be arranged and formed over a large area because of its simple structure and easy manufacture. Therefore, various applications that can take advantage of this feature are being studied. For example, a display device such as a charged beam source and an image display device can be used.

FIG. 13 shows the structure of an electron-emitting device disclosed in Japanese Patent Application Laid-Open No. 2-56822. In the figure, 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is an electron emitting portion. There are various methods for manufacturing the electron-emitting device. For example, the device electrodes 2 and 3 are formed on the substrate 1 by a general vacuum deposition technique and a photolithography technique. Next, a conductive thin film 4 is formed by a dispersion coating method or the like. Thereafter, a voltage is applied to the device electrodes 2 and 3 to perform an energization process, thereby forming the electron-emitting portions 5.

[0008]

However, in the above-mentioned conventional manufacturing method, since the manufacturing is performed mainly by a semiconductor process, it takes a long time, and the current technology forms an electron-emitting device in a large area. However, there are drawbacks in that it is difficult to perform the process, a special and expensive manufacturing apparatus is required, and the production cost is high.

Accordingly, an object of the present invention is to provide a surface conduction electron-emitting device capable of easily forming an electron-emitting device in a large area in a short time at low cost, an electron source substrate having the same, and an image forming apparatus. Is to do.

[0010]

According to the present invention, a solution of a material for forming a conductive film is applied between a pair of device electrodes in the form of droplets to form a conductive film. And, in the method of manufacturing an electron-emitting device, an electron source substrate, or an image forming apparatus for forming an electron-emitting portion on the conductive film, using an inkjet type droplet applying means having a plurality or a single nozzle, The method is characterized in that a plurality of droplets of the material solution are applied at an interval shorter than the diameter of a dot formed by the applied droplets while traveling in a gap direction between the device electrodes. Here, the film thickness of the electron emitting portion can be controlled by the amount of the applied droplets or the number of the droplets. In addition, in the inkjet method, a method using a piezoelectric element or the above-described liquid droplet applying means using a method of generating bubbles by applying thermal energy and ejecting liquid droplets can be used.

According to the above method, a conductive film can be formed without using photolithography technology, and a multi-pattern (hereinafter referred to as a pad) is formed with a plurality of dots. Can be done. Further, in order to form a multi-pattern by scanning in the gap direction between opposing element electrodes and applying a plurality of droplets at intervals shorter than the dot diameter of the droplets in the scanning direction, for example, as shown in FIG. When a large number of elements arranged in a direction perpendicular to the gap direction are formed as described above, scanning can be performed in the arrangement direction, and the scanning can be formed in a shorter time than when scanning is performed a plurality of times while moving in the substrate gap direction.

[0012]

Next, preferred embodiments of the present invention will be described.

As the cold cathode electron source to which the present invention is applied, a surface conduction electron-emitting device having a simple structure and easy to manufacture is preferable.

FIG. 4 is a schematic plan view and a sectional view showing the structure of a basic surface conduction electron-emitting device according to an embodiment of the present invention. In FIG. 4, 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is an electron emitting portion. As the substrate 1, quartz glass, impurity content less glass such as Na, blue plate glass, ceramics substrate such as a glass substrate and an alumina forming the SiO ₂ on the surface used. As a material for the device electrodes 2 and 3, a general conductor is used. For example, Ni, Cr, Au, Mo, W, Pt, Ti,
Metals or alloys such as Al, Cu, Pd, Pd, Ag,
Printed conductor composed of a metal such as Au, RuO ₂ , Pd-Ag or a metal oxide and glass; In ₂ O ₃ —S
It is appropriately selected from a transparent conductor such as nO ₂ or a semiconductor material such as polysilicon.

The distance L between the device electrodes 2 and 3 is preferably several hundred angstroms to several hundred micrometers. Further, it is desirable that the voltage applied between the device electrodes 2 and 3 is low, and it is required to produce the device with good reproducibility. Therefore, the preferable device electrode interval L is several micrometers to several tens of micrometers. The length W1 of the device electrodes 2 and 3 is several micrometers to hundreds of micrometers from the electrode resistance value and electron emission characteristics, and the film thickness d of the device electrodes 2 and 3 is several hundred angstroms to several micrometers. Meters are preferred. The configuration is not limited to the configuration in FIG. 1, and a configuration in which the conductive thin film 4 and the electrodes of the device electrodes 2 and 3 are sequentially formed on the substrate 1 may be employed.

The conductive thin film 4 is particularly preferably a fine particle film composed of fine particles in order to obtain good electron emission characteristics, and the film thickness is determined by the step coverage of the device electrodes 2 and 3 and the device electrodes 2 and 3. It is appropriately set depending on the resistance value between the electrodes and the energizing forming conditions described below, but is preferably several angstroms to several thousand angstroms.
Particularly preferably, it is 10 Å to 500 Å. The sheet resistance value is 10 3 to 10 7 ohm / □.

The material constituting the conductive thin film 4 is P
d, Pt, Ru, Ag, Au, Ti, In, Cu, C
metals such as r, Fe, Zn, Sn, Ta, W, Pb, Pd
Oxides such as O, SnO ₂ , In ₂ O ₃ , PbO, and Sb ₂ O ₃ are mentioned.

The fine particle film described here is a film in which a plurality of fine particles are gathered, and has a fine structure not only in a state in which the fine particles are individually dispersed and arranged, but also in a state in which the fine particles are adjacent to each other or overlap each other (an island). The particle size of the fine particles is from several Angstroms to several thousand Angstroms, preferably from 10 Angstroms to 200 Angstroms.

Next, a method for manufacturing the electron-emitting device shown in FIG. 4, particularly a method for forming a fine particle film constituting the conductive thin film 4, will be described in detail with reference to the drawings.

FIG. 1 is a view showing a method of forming the conductive thin film 4, and FIG. 2 is a view showing a multi-pattern (pad) of liquid droplets of a material for forming the conductive thin film 4.

In FIGS. 1 and 2, reference numeral 6 denotes a droplet applying device;
Are formed after applying the droplet on the substrate 1,
It is a liquid or solid circular film (dot).

As the droplet applying device 6, any device can be used as long as it can form an arbitrary droplet. In particular, the device can be controlled in a range of about several tens to several tens of ng. It is preferable to use an ink jet type apparatus which can easily form a very small amount of droplets of about 10 ng or more and has a plurality of nozzles. As the material of the droplet, any state may be used as long as the droplet can be formed, but a solution in which the above-described metal or the like is dispersed and dissolved in water, a solvent, or the like, a solution of an organic metal, or the like can be used. .

Substrate 1 sufficiently washed with an organic solvent and dried
Next, device electrodes 2 and 3 are formed using a vacuum deposition technique and a photolithography technique. A plurality of dots 4 as shown in FIG. 2 are provided on the substrate 1 to form a multi-pattern (pad). Here, a plurality of dot intervals P1 are provided at intervals shorter than the diameter φ of the dots 4 by scanning the nozzles in the gap direction between the element electrodes 2 and 3. As a result, adjacent dots overlap, the droplets extend on the substrate, and the width W2 becomes substantially constant, thereby forming a pad. The size of the pad is preferably such that the width W2 is equal to or less than the element electrode width W1 and the length T is equal to or greater than the gap interval L1. Further, the size of the pad is determined by the required resistance value, the width and gap width of the element electrode, and the alignment accuracy. You. In FIG. 2B, the pad is formed by six droplets, but the present invention is not limited to this, and a plurality of droplets may be used. Further, instead of a single line as shown in FIG. 2B, a plurality of lines may be formed as shown in FIG. 3B.

After the droplets are applied by the above method, a heat treatment is performed at a temperature of 300 to 600 degrees to evaporate the solvent to form the conductive thin film 4.

The electron-emitting device shown in FIG. 4 will be described. The electron-emitting portion 5 is a high-resistance crack formed in a part of the conductive thin film 4, and is formed by energization forming or the like. The crack may have conductive fine particles having a particle size of several Angstroms to several hundred Angstroms. The conductive fine particles contain at least some of the elements constituting the conductive thin film 4. Further, the electron emitting portion 5 and the conductive thin film 4 in the vicinity thereof may contain carbon or a carbon compound.

In an energization process called energization forming, an energization is performed between the element electrodes 2 and 3 from a power source (not shown) to locally destroy, deform or alter the conductive thin film 4, thereby forming a portion having a changed structure. Things. The site where the structure is locally changed is the electron emitting portion 5. FIG. 5 shows an example of the voltage waveform of the energization forming.

The voltage waveform is particularly preferably a pulse waveform. When a voltage pulse having a constant pulse peak value is continuously applied (FIG. 5A), when a voltage pulse is applied while increasing the pulse peak value (FIG. 5B). First, the case where the pulse peak value is a constant voltage (FIG. 5A) will be described.

In FIG. 5A, T1 and T2 are the pulse width and pulse interval of the voltage waveform. T1 is 1 microsecond to 10 milliseconds, T2 is 10 microseconds to 100 milliseconds, and the peak value of the triangular wave ( The peak voltage at the time of energization forming is appropriately selected according to the form of the surface conduction electron-emitting device, and is applied for several seconds to several tens of minutes under a vacuum atmosphere having an appropriate degree of vacuum, for example, about 10 −5 torr. . The waveform applied between the device electrodes is not limited to a triangular wave,
A desired waveform such as a rectangular wave may be used.

T1 and T2 in FIG.
As in (a), the peak value of the triangular wave (peak voltage at the time of energization forming) is increased in steps of, for example, about 0.1 V and applied under an appropriate vacuum atmosphere.

In the energization forming process in this case, the element current is measured at a voltage that does not locally destroy or deform the conductive thin film 4 during the pulse interval T2, for example, a voltage of about 0.1 V, and the resistance value is measured. The energization forming is terminated when, for example, a resistance of 1 M ohm or more is indicated.

Next, it is desirable to perform a process called an activation process on the element after the energization forming. The activation process is, for example, a process of repeatedly applying a voltage pulse having a constant pulse peak value at a degree of vacuum of about 10 −4 to 10 −5 torr, as in the energization forming. Is deposited on the conductive thin film 4 by carbon or a carbon compound caused by an organic substance existing in the device.
f, a process for significantly changing the emission current Ie. The activation step measures the device current If and the emission current Ie,
For example, the process ends when the emission current Ie is saturated. Further, it is preferable that the applied voltage pulse be performed at an operation drive voltage.

Here, the carbon or carbon compound is
Graphite (indicating both single crystal and polycrystalline) and amorphous carbon (indicating a mixture of amorphous carbon and polycrystalline graphite). The film thickness is preferably 500 Å or less, more preferably 300 Å or less. It is.

The electron-emitting device thus prepared is preferably operated and driven in an atmosphere having a degree of vacuum higher than the degree of vacuum in the energization forming step and the activation step. Further, it is desirable to drive the device after heating at 80 ° C. to 150 ° C. in an atmosphere with a higher vacuum degree. The vacuum degree higher than the vacuum degree after the forming step and the activation treatment is, for example, a vacuum degree of about 10 −6 or more, more preferably an ultra-high vacuum system, in which carbon or a carbon compound is newly formed of a conductive thin film. 4 is a degree of vacuum that hardly accumulates. This makes it possible to stabilize the element current If and the emission current Ie.

Next, the image forming apparatus will be described. An electron source substrate used in an image forming apparatus is formed by arranging a plurality of surface conduction electron-emitting devices on a substrate. As a method of arranging the surface-conduction electron-emitting devices, the surface-conduction electron-emitting devices are arranged in parallel, and both ends of each element are connected by wiring. Another example is a simple matrix arrangement in which an X-direction wiring and a Y-direction wiring are connected to a pair of device electrodes of a surface conduction electron-emitting device (hereinafter, referred to as a matrix-type arrangement electron source substrate). Note that an image forming apparatus having a ladder-type electron source substrate requires a control electrode (grid electrode) which is an electrode for controlling the flight of electrons from the electron-emitting devices.

The structure of the electron source having the simple matrix arrangement will be described below with reference to FIG. 61 is an electron source substrate, 6
2 is an X-direction wiring, 63 is a Y-direction wiring, 64 is a surface conduction electron-emitting device, and 65 is a connection. The substrate used as the electron source substrate 61 is the above-described glass substrate or the like, and the shape is appropriately set according to the application. The m X-direction wires 62 are DX
, DX2,..., DXm, and the Y-direction wiring 63 is composed of n wirings DY1, DY2,.
Further, the material, the film thickness, and the wiring width are appropriately set so that a substantially uniform voltage is supplied to many surface conduction elements 64. The m X-directional wirings 62 and the n Y-directional wirings 63 are electrically separated by an interlayer insulating layer (not shown) to form a matrix wiring (m and n are both positive integers).

The interlayer insulating layer (not shown) is formed in a part of a desired region on the entire surface of the substrate 61 on which the X-directional wiring 62 is formed. The X-direction wiring 62 and the Y-direction wiring 63 are led out as external terminals. Further, the element electrodes (not shown) of the surface conduction electron-emitting device 64 are electrically connected to the m X-directional wirings 62 and the n Y-directional wirings 63 by connection 65. The surface conduction electron-emitting device 64 may be formed on either the substrate or an interlayer insulating layer (not shown).

As will be described in detail later, the X-direction wiring 62
Are electrically connected to a scanning signal generating means (not shown) for applying a scanning signal for scanning a row of the surface conduction electron-emitting devices 64 arranged in the X direction according to an input signal. On the other hand, the Y-direction wiring 63 is electrically connected to a modulation signal generating means (not shown) for applying a modulation signal for modulating each column of the surface conduction electron-emitting devices 64 arranged in the Y direction according to an input signal. It is connected. Further, the driving voltage applied to each element of the surface conduction electron-emitting device 64 is supplied as a difference voltage between a scanning signal and a modulation signal applied to the element. As a result, individual elements can be selected and driven independently using only simple matrix wiring.

Next, an image forming apparatus using the electron sources having the simple matrix arrangement prepared as described above will be described with reference to FIGS. 7, 8 and 9. FIG. FIG. 7 is a basic configuration diagram of a display panel of an image forming apparatus, and FIG. 8 shows a fluorescent film used for the display panel. FIG. 9 shows a block diagram of a drive circuit for performing display in accordance with an NTSC television signal, and shows an image forming apparatus including the drive circuit.

In FIG. 7, reference numeral 61 denotes an electron source substrate on which an electron-emitting device 64 is formed, 71 is a rear plate on which the electron source substrate 61 is fixed, and 76 is a fluorescent film 74 and a metal back 75 on the inner surface of a glass substrate 73. And a support frame 72. The rear plate 71, the support frame 72, and the face plate 76 are coated with frit glass or the like and baked in the air or nitrogen at 400 to 500 degrees for 10 minutes or more. Then, sealing is performed to form the envelope 78. Reference numeral 5 denotes an electron emission portion of the electron emission element 64;
Are X-direction wiring and Y-direction wiring connected to a pair of device electrodes of each surface conduction electron-emitting device 64.

The envelope 78 includes the face plate 76, the support frame 72, and the rear plate 71 as described above.
Since the rear plate 71 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 61, if the electron source substrate 61 itself has sufficient strength, the separate rear plate 71 is unnecessary, and The support frame 72 may be directly sealed, and the envelope 78 may be constituted by the face plate 76, the support frame 72, and the electron source substrate 61. Further, by providing an anti-atmospheric pressure support member called a spacer between the face plate 76 and the rear plate 71, the envelope 78 having sufficient strength against atmospheric pressure can be obtained.

In FIG. 8, reference numeral 82 denotes a phosphor constituting the phosphor film 74. The phosphor 82 is composed of only the phosphor in the case of a monochrome, but is composed of a black conductive material 81 called a black stripe or a black matrix depending on the arrangement of the phosphor in the case of a color phosphor film. The purpose of providing the black stripes and the black matrix is to make the color separation and the like inconspicuous by making the painted portions between the phosphors 82 of the necessary three primary color phosphors black in color display, The purpose is to suppress a decrease in contrast due to light reflection. 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.

As a method of applying a fluorescent substance to the glass substrate 73, a precipitation method or a printing method is used regardless of monochrome or color. A metal back 75 (FIG. 7) is usually provided on the inner surface side of the fluorescent film 74 (FIG. 7). The metal back 75 improves the brightness by reflecting the light toward the inner surface side of the light emitted from the phosphor to the face plate 76 side to improve the brightness, acts as an electrode for applying an electron beam acceleration voltage, and It has a role of protecting the phosphor from damage due to collision of negative ions generated in the vessel.
The metal back 75 can be manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 74 after manufacturing the fluorescent film 74, and then depositing A1 by vacuum evaporation or the like.

The face plate 76 further includes a fluorescent film 7.
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 74 in order to increase the conductivity of the fluorescent film 74.

When performing the above-described sealing, in the case of color, the phosphors of each color must correspond to the electron-emitting devices, and it is necessary to perform sufficient alignment.

The envelope 78 passes through an exhaust pipe (not shown) and
^The degree of vacuum is set to about ^-7 torr, and sealing is performed.

In some cases, a getter process is performed to maintain the degree of vacuum after the envelope 78 is sealed. This is accomplished by heating a getter disposed at a predetermined position (not shown) in the envelope 78 by a heating method such as resistance heating or high-frequency heating immediately before or after the envelope 78 is sealed, and vapor deposition. This is a process for forming a film. A getter typically contains Ba as a principal component, the adsorption effect of the vapor deposition film, for example, 1 × 10 ^-5
This is to maintain the degree of vacuum from torr to 1 × 10 ⁻⁷ torr. Steps after the energization forming of the surface conduction electron-emitting device are appropriately set.

Next, by driving this display panel constituted by using an electron source having a simple matrix arrangement type substrate, N
A schematic configuration of a drive circuit for performing television display based on a TSC television signal will be described with reference to FIG.
91 is the display panel, 92 is a scanning circuit, 93 is a control circuit, 94 is a shift register, 95 is a line memory, 96
Is a synchronization signal separation circuit, 97 is a modulation signal generator, and Vx and Va are DC voltage sources.

The function of each section will be described below. First, the display panel 91 is connected to the terminals Dox1 to Doxm and the terminal Dx1.
It is connected to an external electric circuit via oy1 to Doyn and the high voltage terminal Hv. Of these terminals, the terminals Dox1 to Doxm sequentially drive electron sources provided in the display panel 91, that is, a group of surface conduction electron-emitting devices arranged in a matrix of M rows and N columns, one row at a time (N elements). A scanning signal for moving is applied. On the other hand, terminal D
To oy1 to Doyn, a modulation signal for controlling the output electron beam of each element of the one row of surface conduction electron-emitting devices selected by the scanning signal is applied. Further, for example, 10K [V] is applied to the high voltage terminal Hv from the DC voltage source Va.
This is an accelerating voltage for applying sufficient energy to the electron beam output from the surface conduction electron-emitting device to excite the phosphor.

Next, the scanning circuit 92 will be described. This circuit has M switching elements inside (in the figure, S1 to Sm are schematically shown), and each switching element is provided with an output voltage of a DC voltage source Vx or 0V.
[V] (ground level) is selected and electrically connected to the terminals Dox1 to Doxm of the display panel 91. Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 93, but can be actually configured by combining switching elements such as FETs. Note that the DC voltage source Vx is such that the drive voltage applied to an element that is not scanned based on the characteristics (electron emission threshold voltage) of the surface conduction type electron emission element is equal to or lower than the electron emission threshold voltage. It is set to output a constant voltage.

The control circuit 93 has a function of matching the operations of the respective units so that appropriate display is performed based on an externally input image signal. Tscan, Tsft, and Tmr for each unit based on a synchronization signal Tsync sent from a synchronization signal separation circuit 96 described below.
Generate y control signals.

The synchronizing signal separating circuit 96 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and can be formed by using a frequency separating (filter) circuit. It is.
As is well known, the synchronization signal separated by the synchronization signal separation circuit 96 is composed of a vertical synchronization signal and a horizontal synchronization signal, but is shown here as a Tsync signal for convenience of explanation. On the other hand, a luminance signal component of an image separated from the television signal is referred to as a DATA signal for convenience, and the signal is input to a shift register 94.

The shift register 94 is for serially / parallel converting the DATA signal input serially in time series for each line of an image, and operates based on a control signal Tsft sent from the control circuit 93. I do. That is, the control signal Tsft is
May be rephrased as the shift clock. One line of serial / parallel converted image (electron emitting element N
(Corresponding to the drive data for the elements) is output from the shift register 94 as N parallel signals Id1 to Idn.

The line memory 95 is a storage device for storing data for one line of an image for a required time only.
The contents of Id1 to Idn are stored as appropriate according to the control signal Tmry sent from the control circuit 93. The stored contents are output as Id1 to Idn and input to the modulation signal generator 97.

The modulation signal generator 97 outputs the image data Id
A signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices according to each of 1 to Idn, and an output signal thereof is sent to the surface conduction electron-emitting device in the display panel 91 through terminals Doy1 to Doyn. Applied.

As described above, the electron-emitting device according to the present invention has the following basic characteristics with respect to the emission current Ie. That is, as described above, electron emission has a clear threshold voltage Vth, and electron emission occurs only when a voltage higher than Vth is applied. For a voltage equal to or higher than the electron emission threshold, the emission current also changes in accordance with the change in the voltage applied to the device. Note that the value of the electron emission threshold voltage Vth and the degree of change of the emission current with respect to the applied voltage may be changed by changing the material, configuration, and manufacturing method of the electron emission element. I can say that.

That is, when a pulse-like voltage is applied to the present element, for example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur but a voltage higher than the electron emission threshold is applied. Outputs an electron beam. that time,
First, it is possible to control the intensity of the output electron beam by changing the pulse peak value Vm. Second, it is possible to control the total amount of charges of the output electron beam by changing the pulse width Pw.

Therefore, as a method of modulating the electron-emitting device in accordance with the input signal, a voltage modulation method, a pulse width modulation method and the like can be mentioned. A voltage modulation circuit is used which generates a voltage pulse having a length of, but modulates the peak value of the pulse appropriately according to input data. In order to implement the pulse width modulation method, the modulation signal generator 97 generates a voltage pulse having a constant peak value, but the pulse width is such that the width of the voltage pulse is appropriately modulated according to input data. A modulation type circuit is used.

Through the series of operations described above, the image display device can display a television using the display panel 91. Although not particularly described in the above description, the shift register 94 and the line memory 95 may be of a digital signal type or an analog signal type. In short, serial / parallel conversion and storage of image signals are performed at a predetermined speed. It should be done in.

When using a digital signal type,
It is necessary to convert the output signal DATA of the synchronization signal separation circuit 96 into a digital signal. This can be achieved by providing an A / D converter at the output of the synchronization signal separation circuit 96. In connection with this, the circuit used for the modulation signal generator 97 differs slightly depending on whether the output signal of the line memory 95 is a digital signal or an analog signal.

First, the case of a digital signal will be described.
In the voltage modulation method, for example, a well-known D / A conversion circuit may be used as the modulation signal generator 97, and an amplification circuit or the like may be added as necessary. In the case of the pulse width modulation system, the modulation signal generator 97 compares, for example, a high-speed oscillator, a counter (counter) for counting the number of waves output from the oscillator, and an output value of the counter with an output value of the line memory 95. It can be configured by using a circuit in which a comparator (comparator) is combined. 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 may be added.

Next, the case of an analog signal will be described.
In the voltage modulation method, for example, an amplification circuit using a well-known operational amplifier or the like may be used as the modulation signal generator 97, and a level shift circuit or the like may be added as necessary. In the case of the pulse width modulation method, for example, a well-known voltage controlled oscillator (VCO) may be used.
If necessary, an amplifier for amplifying the voltage up to the drive voltage of the surface conduction electron-emitting device may be added.

In the image display device having the above-described structure, the electron-emitting devices of the display panel 91 are provided with external terminals Dox1 to Doxm, Doy1 to Doyn.
Through the high voltage terminal Hv to apply a high voltage to the metal back 75 or a transparent electrode (not shown) to accelerate the electron beam, collide with the fluorescent film 84, and excite An image can be displayed by emitting light.

The structure described above is a schematic structure necessary for manufacturing a suitable image forming apparatus used for display and the like. For example, detailed portions such as materials of each member are not limited to the above-described contents. Is appropriately selected so as to be suitable for the use of the image forming apparatus. Also, the NTSC system has been described as an example of the input signal, but the present invention is not limited to this, and PAL, SECA
Various systems such as the M system may be used, and a TV signal (for example, a commercial TV including the MUSE system) including a large number of scanning lines may be used.

Next, the above-mentioned ladder-type arrangement electron source substrate and an image display device using the same will be described with reference to FIGS.

In FIG. 10, 101 is an electron source substrate, 1
02 is an electron-emitting device, 103 is a common wiring connected to the electron-emitting device 110 and Dx1 to Dx10. A plurality of electron-emitting devices 101 are arranged on the substrate 101 in parallel in the X direction. This is called an element row. A plurality of such element rows are arranged on a substrate to form a ladder-type electron source substrate. By appropriately applying a drive voltage between the common wires of each element row, each element row can be driven independently. That is,
A voltage equal to or higher than the electron emission threshold may be applied to an element row that emits an electron beam, and a voltage equal to or lower than the electron emission threshold may be applied to an element row that does not emit an electron beam. Further, common wirings Dx2 to Dx9 between the element rows, for example, Dx
2, Dx3 may be the same wiring.

FIG. 11 shows the structure of an image forming apparatus having such a ladder-type arrangement of electron sources. 111 is a grid electrode, 112 is a hole through which electrons pass, 113
Are external terminals made of Dox1, Dox2... Doxm, and 114 are G1, connected to the grid electrode 111.
.., Gn, the external terminal 115 is an electron source substrate in which the common wiring between the element rows is the same as described above. 7 and 10 indicate the same members. The difference from the image forming apparatus having the simple matrix arrangement (FIG. 7) is that a grid electrode 111 is provided between the electron source substrate 115 and the face plate 76.

The grid electrode 111 is capable of modulating the electron beam emitted from the surface conduction electron-emitting device, and passes the electron beam to a stripe-shaped electrode provided orthogonally to the ladder-shaped device row. For this purpose, one circular opening 112 is provided for each element 102. The shape and the installation position of the grid need not always be as shown in FIG. 11, and a large number of openings may be provided in the form of a mesh as openings. For example, the openings may be provided around or near the surface conduction electron-emitting device 102. Good.

The outer container terminal 113 and the grid outer terminal 114 are electrically connected to a control circuit (not shown).

In this image forming apparatus, the modulation signals for one line of an image are simultaneously applied to the grid electrode columns in synchronization with the sequential driving (scanning) of the element rows one by one.
By controlling the irradiation of each electron beam to the phosphor, an image can be displayed line by line.

According to this, it is possible to provide an image forming apparatus suitable for a display device such as a television conference system and a computer as well as a display device for a television broadcast.
Further, it can be used as an image forming apparatus as an optical printer including a photosensitive drum or the like.

In the image forming apparatus, not only the surface conduction type electron-emitting device but also the MIM
The present invention can be applied to a cold cathode electron source using a type electron emission element, a field emission type electron emission element, or the like, and further to an image display device using a thermionic electron source.

[0072]

[Example 1] Through the following steps (1) to (3), device electrodes wired in a matrix were formed on a substrate to produce a surface conduction electron-emitting device. 1 and 2 are views showing the manufacturing method. FIG. 3A is a plan view of a surface conduction electron-emitting device manufactured according to this embodiment.

A quartz substrate was used as the insulating substrate 1, which was sufficiently washed with an organic solvent or the like, and then dried at 120 ° C.

Next, the device electrodes 2 and 3 made of Ni were formed on the substrate 1 by using a general vacuum film forming technique and a photolithography technique. Gap interval L between device electrodes
1 was 200 μm, the width W1 of the device electrode was 600 μm, and the thickness d was 1000 °.

Next, an ink-jet type droplet applying device using a piezoelectric element, which is adjusted so that the dot diameter φ becomes 100 μm, is prepared as the droplet applying device 6, and the device is scanned in the gap direction. An organic palladium-containing solution (Ccp-4230, Okuno Pharmaceutical Co., Ltd.) was applied between the electrodes 2 and 3 at intervals of 50 μm shorter than the dot diameter of the droplet as shown in FIG. In this manner, by applying six 100 μm dots at a pitch P1 of 50 μm in the scanning direction with respect to a gap of 200 μm, the overlapping portion of the dots is widened, and the edge in the length direction is linear. . That is, the width W2 = 100 μm and the length T = 350 μm
Was formed in one dot row (pad).

Next, a heat treatment was performed at 300 ° C. for 10 minutes to form a fine particle film made of palladium oxide (PdO) fine particles, thereby forming a thin film 4.

Next, a voltage is applied between the electrodes 2 and 3,
The electron emission portion 5 was formed by applying a current to the thin film 4 (forming process).

In the electron source substrate prepared by the above-described method, the width W2 of the pad becomes constant by applying dots in a single pad, and the variation in the width W2 due to the displacement in the length direction. However, since the coating was uneven and the film thickness distribution was small, the variation in resistance was also small.
Further, the pad of the fine particle film made of PdO has a margin of several tens of μm in the vertical direction and the horizontal direction with respect to the gap between the device electrodes, so that the alignment becomes easy and the defects due to the displacement are reduced.

Further, since the pad is formed by one scan by scanning in the gap direction, the electron source substrate can be formed in a short time.

When the number of droplets per dot is set to 2, the film thickness becomes about twice and the resistance becomes about half. By changing the number of droplets per dot, a desired conductive thin film resistor is obtained. I was able to. Further, when the amount of droplets per dot is doubled, the same result as that obtained when the number of droplets is 2 is obtained. By changing the amount of droplets per dot, a desired conductive thin film is obtained. Resistance was obtained.

As described above, when a plurality of elements are formed, variation between the elements can be reduced, and the production yield is improved.

Using the electron source substrate thus manufactured,
An envelope was formed with the above-described face plate, support frame, and rear plate, sealing was performed, and a display panel, and further, an image forming apparatus having a driving circuit for performing television display was manufactured. And few defects. Further, since the patterning of the thin film 4 can be omitted, the cost can be reduced.

[Embodiment 2] The device electrode width W1 was set to 600 μm.
m, the device electrode gap interval L1 was 200 μm, and the thickness d of the device electrode was 1000 °. Using a substrate having device electrodes wired in a ladder shape, a surface conduction electron-emitting device was fabricated in the same manner as in Example 1. Produced. Using the obtained electron source substrate, an envelope was formed with a face plate, a support frame, and a rear plate in the same manner as in Example 1, and sealing was performed to produce an image forming apparatus. As a result, the same effect as in the first embodiment was obtained.

Embodiment 3 FIG. 3B is a plan view of a surface conduction electron-emitting device manufactured according to this embodiment.

As in the first embodiment, when the gap interval L1 is 2
00 μm, electrode width W1 is 600 μm, and thickness d is 1.
The organic palladium-containing solution was applied to the substrate on which the device electrodes of 2,000 mm were formed by an ink jet ejecting apparatus using the same piezoelectric element as in Example 1. At this time, the nozzles are arranged perpendicular to the gap, scanned in the gap direction, six dots are provided at 50 μm intervals in the scanning direction, and the substrate is fed 50 μm in the direction perpendicular to the scanning direction. Scan in the gap direction and at intervals of 50 μm in the scanning direction.
Dots were provided as in (b). That is, 200 μm
The dots having a diameter φ of 100 μm were provided in two rows of six in each row so as to overlap the left, right, upper and lower dots by 50 μm. That is, width W2 = 150 μm, length T
= 350 μm rectangular pad was formed. Except for the shape of the pad, it was manufactured in the same manner as in Example 1.
The same good results as in the above with little variation between elements were obtained. Accordingly, the pad width W2 is equal to the device electrode width W1.
Hereinafter, the required resistance value, the width of the element electrode, and the gap width can be determined based on the alignment accuracy.

[Embodiment 4] Instead of the ink jet ejection apparatus using a piezoelectric element used in Embodiments 1 to 3, a droplet applying apparatus of a system for generating bubbles by applying thermal energy and ejecting liquid droplets is used. When used, a similar effect was obtained.

[Embodiment 5] FIG. 3C is a plan view showing a production method of the present embodiment. As shown in the drawing, a ladder-shaped electron source substrate produced in the same manner as in Example 1 with an element interval P4 of 1000 μm and a nozzle pitch P3 of 200 μm and 6 μm.
In the step of applying the same organic-containing solution as in Example 1 using a droplet applying apparatus having three nozzles, the nozzle rows are arranged in parallel with the gap direction, and the nozzles are numbered.
In the same manner as in the first embodiment, the nozzles are scanned in the gap direction from nozzles 1 and 6 simultaneously to two elements, and a plurality of droplets are applied at intervals shorter than the dot diameter of the droplets in the scanning direction. (Pad) was formed.
Similarly, an element having a small variation can be formed in half the time required for coating with one nozzle.

[0088]

As described above, according to the present invention, an ink-jet type droplet applying means having a plurality or a single nozzle is used, and the nozzle is applied while traveling in the gap direction between the element electrodes. Since the plurality of droplets of the material solution are applied at intervals shorter than the diameter of the dot formed by the droplet formed, the conductive film can be formed in a short time without using photolithography technology, with less variation. can do. Therefore,
It is possible to reduce the cost of manufacturing the image forming apparatus and improve the yield. Further, since the width of the conductive film is constant, the display brightness of the image forming apparatus can be made uniform.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a method for manufacturing a basic surface conduction electron-emitting device according to an embodiment of the present invention.

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

FIG. 3 is a view showing a droplet application pattern in manufacturing the surface conduction electron-emitting device according to Examples 1 and 3 of the present invention.

FIG. 4 is a configuration diagram of a basic surface conduction electron-emitting device according to an embodiment of the present invention.

FIG. 5 is a diagram showing a voltage waveform example of energization forming applicable to the present invention.

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

FIG. 7 is a schematic configuration diagram of a display panel of an image forming apparatus to which the present invention can be applied.

FIG. 8 is a diagram illustrating a phosphor film of the display panel of FIG. 7;

9 is a block diagram of a driving circuit for performing display on the display panel of FIG. 7 in response to an NTSC television signal, and an image display device having the driving circuit.

FIG. 10 is a diagram showing an electron source having a ladder arrangement to which the present invention can be applied.

FIG. 11 is a schematic configuration diagram of a display panel of another image forming apparatus to which the present invention can be applied.

FIG. 12 is a view showing a conventional electron-emitting device.

FIG. 13 is a configuration diagram of another conventional electron-emitting device.

[Explanation of symbols]

1: substrate, 2, 3: element electrode, 4: conductive thin film, 5: electron emitting portion, 6: droplet applying device, 7: droplet, 61: electron source substrate, 62: X direction wiring, 63: Y Directional wiring, 64: surface conduction electron-emitting device, 65: connection, 71: rear plate, 72: support frame, 73: glass substrate, 74: fluorescent film,
75: metal back, 76: face plate, 77:
High voltage terminal, 78: envelope, 81: black conductive material, 82: phosphor, 83: glass substrate, 91: display panel, 92: scanning circuit, 93: control circuit, 94: shift register, 9
5: line memory, 96: synchronous signal separation circuit, 97: modulation signal generator, Vx and Va: DC voltage source, 101: electron source substrate, 102: electron emission element, 103: Dx1 to Dx
x10 is a common wiring for wiring the electron-emitting devices,
111: grid electrode, 112: hole for passing electrons, 113: Dox1, Dox2,..., An external terminal made of Doxm, 114: G1, G2,... Connected to grid electrode # 120 .... Outer terminal made of Gn, 1
15: electron source substrate.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 9/02 H05K 3/10-3/12 H01B 13/00

Claims (5)

(57) [Claims] An electron emission device for applying a solution of a material for forming a conductive film in the form of a droplet between a pair of device electrodes to form a conductive film, and forming an electron emission portion in the conductive film. In the method of manufacturing the element, the diameter of the dot formed by the applied liquid droplets while moving the nozzle in the gap direction between the element electrodes by using an ink jet type liquid droplet applying means having a plurality or a single nozzle. A method for manufacturing an electron-emitting device, comprising applying a plurality of droplets of the material solution at shorter intervals. 2. The method of manufacturing an electron-emitting device according to claim 1, wherein the film thickness of the conductive film on which the electron-emitting portion is formed is controlled by the amount of applied droplets or the number of droplets. Method. 3. The electron-emitting device according to claim 1, wherein said droplet applying means is used in said ink-jet method, in particular, a method in which bubbles are generated by applying thermal energy and droplets are ejected. Production method. 4. A method for manufacturing an electron source substrate, comprising: manufacturing an electron source substrate using the method for manufacturing an electron-emitting device according to claim 1. 5. A method for manufacturing an image forming apparatus, comprising: manufacturing an image forming apparatus using the method for manufacturing an electron-emitting device according to claim 1.