JP2000251633A - Electron source substrate and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce instability in formation or activation processes by setting the softening point of the base body of a substrate, having a number of electron emitting elements arranged thereon and having a pair of element electrodes and a conductive thin film having an electron emission part to a specified temperature or higher. SOLUTION: A base body 1 of this electron source substrate has a softening point of 750 deg.C or higher, and borosilicate glass, soda lime glass, zinc borosilicate glass, or alumino borosilicate glass is used therefor, so that softening of a substrate near an electron emission part 5 and the deformation of the electron emission part are thereby suppressed. A surface conductive type electron emitting element is desirably used as the electron emitting element. A deposit composed mainly of carbon or a carbon compound and a thin film mainly composed of Pd or PdO are desirably used as an electron emission part 5 and a conductive thin film 4, respectively. A plurality of electron emitting elements is arranged in parallel on the substrate, and element electrodes are connected to mutually insulated X-direction and Y-direction metal wirings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electron source substrate using an electron-emitting device, and an image forming apparatus using the electron source substrate.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus using an electron-emitting device, an electron source substrate on which a large number of cold cathode electron-emitting devices are formed and an anode substrate provided with a transparent electrode and a phosphor are opposed in parallel to each other. 2. Description of the Related Art A flat-type electron beam display panel that has been exhausted is known. In such an image forming apparatus, the one using a field emission type electron emitting element is, for example,
I. Brodie, "Advanced Techn
ology: flat cold-cathode C
RTs ", Information Display,
1/89, 17 (1989).
A device using a surface conduction electron-emitting device is disclosed in, for example, US Pat. No. 5,066,883. A flat-type electron beam display panel can achieve a lighter weight and a larger screen than a cathode ray tube (CRT) display device which is widely used at present, and a flat-type display using liquid crystal. As compared with other flat display panels such as a panel, a plasma display, and an electroluminescent display, an image with higher brightness and higher quality can be provided. In particular, surface-conduction electron-emitting devices have a simple structure and are easy to manufacture, and a large number of devices are arranged over a large area without going through the complicated manufacturing process that uses photolithography technology like field-emission electron-emitting devices. There is an advantage that the formed electron source substrate can be manufactured.

FIGS. 9 and 10 show an example of an electron source substrate using a surface conduction electron-emitting device disclosed by the present applicant in Japanese Patent Application Laid-Open No. 06-342636. FIG. 9 shows a plan view of a part of the electron source.
Here, 7 is an upper wiring, 6 is a lower wiring, 81 is a surface conduction electron-emitting device, and 8 is an interlayer insulating layer. FIG. 10 is a perspective view of the surface conduction electron-emitting device 81 shown in FIG. In FIG. 10, 91 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film having an electron emitting portion, 95 is an electron emitting portion, and the device electrodes 2 and 3 are connected to a lower wiring 6 and an upper wiring 7, respectively. The lower wiring 6 and the upper wiring 7 are electrically insulated by the interlayer insulating layer 8. Here, a predetermined voltage is sequentially applied to the upper wiring 7 and the lower wiring 6 arranged in a matrix as a scanning signal and an information signal, respectively, so that a predetermined electron-emitting device located at the intersection of the matrix is selectively driven. it can.

[0004] Such an electron source substrate arranged in a matrix can be manufactured by using a relatively simple photolithography technique, but when a larger substrate is formed, it is preferable to use a printing technique. In particular, as for the upper wiring to which a scanning signal is applied, since the amount of current flowing through the wiring increases as the number of elements connected to one line increases, a voltage drop occurs due to wiring resistance. Preferably, the resistance is as low as possible.
Japanese Patent Application Laid-Open No. 08-180797 discloses a manufacturing method for forming a wiring and an interlayer insulating layer by a screen printing method. Regarding other members, for example, Japanese Patent Application Laid-Open No. 09-17333 discloses a manufacturing method of forming element electrodes by an offset printing method or the like. For a conductive thin film, a manufacturing method of forming an element electrode by an inkjet method is disclosed. It is disclosed in JP-A-09-69334. By using these printing techniques, a large-area electron source substrate can be easily manufactured.

Next, a surface conduction electron-emitting device will be described. The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted by passing a current through a small-area conductive thin film formed on a substrate in parallel with the film surface. As the surface conduction electron-emitting device, a device using a SnO ₂ thin film [M. I. Elinson, Radio En
g. Electron Phys. , 10,1290,
(1965)], an Au thin film [G. Ditmm
er, Thin Solid Films, 9, 317
(1972)], using an In ₂ O ₃ / SnO ₂ thin film [M. Hartwell and C.M. G. FIG. Fonst
ed, IEEE Trans. ED Conf. , 51
9 (1975)], a method using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, p. 22 (1983)] and the like have been reported.
JP-A-56822 discloses a surface conduction electron-emitting device using a metal fine particle film of palladium oxide or the like.

In manufacturing a surface conduction electron-emitting device, an electron-emitting portion is generally formed on a conductive thin film by an energization process called forming. Forming is a process of applying a direct current voltage or a very slowly increasing voltage, for example, about 1 V / min, to both ends of a conductive thin film and energizing the conductive thin film to locally destroy, deform or alter the conductive thin film, thereby forming a gap. is there. After the forming process, a voltage is applied to the conductive thin film,
By passing a current through the element, electrons are emitted from the vicinity of the gap. At this time, a portion from which electrons are emitted is called an electron emitting portion.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-235255, the present applicant can apply a process called an activation process to an element after forming to obtain better electron emission. it can. The activation step can be performed by repeatedly applying a pulse voltage to the device in an atmosphere containing a gas of an organic substance, similarly to the forming treatment. From the organic substance present in the atmosphere, carbon or a carbon compound can be obtained. The element current If and the emission current Ie are remarkably increased.

A surface conduction electron-emitting device manufactured through such a process has sufficient electron emission characteristics as an electron source applicable to an image forming apparatus such as a flat panel display.

Accordingly, as described above, a large-area image forming apparatus, for example, a large-screen flat panel display is manufactured by manufacturing a large-area electron source substrate composed of surface conduction electron-emitting devices by using the printing technique. Can be realized.

[0010]

When an electron-emitting device having a sufficient electron emission amount, a long life, and stability is formed on a large-sized electron source substrate, there are the following problems. If an attempt is made to manufacture a large-area electron source substrate at low cost, it is necessary to reduce the cost of the members used, and soda lime glass is preferably used as the base. However, since the surface-conduction electron-emitting device has an electron-emitting portion formed in contact with the surface of the substrate, a heat process at the time of forming the device,
Alternatively, heat generated when the element is driven is transmitted to the surface of the glass substrate.

At this time, in the case of a substrate having a relatively low softening point, such as soda lime glass, the surface of the substrate in the vicinity of the electron-emitting device is softened, and the electron-emitting portion in contact with the glass substrate is deformed. This causes instability of the formation process and fluctuation or deterioration of the electron emission characteristics.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, that is, when the surface of the base material is softened by the heat generation of the electron-emitting device and the electron-emitting portion is deformed, the device forming process such as the forming step becomes unstable. This is intended to solve the problem that the electron emission characteristics fluctuate or deteriorate, and have the configuration described below.

That is, an electron source substrate of the present invention is an electron source substrate having a base and a plurality of electron-emitting devices provided on the base and having a conductive thin film between a pair of device electrodes. The softening point of the substrate is 750 ° C. or higher.

Here, as the conductive thin film, a thin film containing Pd or PdO or a mixture thereof as a main component is preferably used. As the electron-emitting device, a surface-conduction electron-emitting device is preferably used, and as the conductive thin film, carbon or a carbon compound, or a material having a deposit containing these as a main component can be preferably used. .

According to the present invention, there is provided an electron source substrate for arranging a plurality of the above-mentioned electron-emitting devices on a substrate, an electron source substrate for emitting electrons according to an input signal, and a plurality of the electron-emitting devices arranged in parallel on the substrate. It has a plurality of rows of electron-emitting devices in which both ends of each element are connected to a metal wiring, and further comprises an electron source substrate having a modulation means, and m X-direction metal wirings and n wirings electrically insulated from each other on the substrate. The present invention is preferably applied to an electron source substrate in which a plurality of electron-emitting devices in which a Y-direction metal wiring is connected to a pair of device electrodes of the electron-emitting device are arranged.

Further, the present invention also includes an image forming apparatus for forming an image based on an input signal, comprising an image forming member and the above-mentioned electron source substrate.

[0017]

According to the present invention, by using a substrate having a high softening point as the electron source substrate, it is possible to suppress the softening of the substrate surface near the electron emitting portion and the deformation of the electron emitting element due to the softening. The instability in the process of formation is reduced, and a stable and reproducible electron source substrate can be manufactured. Further, softening of the base due to heat generation during driving of the electron-emitting device and deformation of the electron-emitting device due to the softening can be prevented, so that stable and good electron emission characteristics can be obtained for a long time.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram (plan view) showing an example of the electron source substrate of the present invention, and shows only a part of the electron source substrate. FIG. 2 is an enlarged bird's-eye view of one electron-emitting device of the electron source substrate shown in FIG. FIG. 3 is a cross-sectional view taken along the line AA ′ in FIG.

1, 2 and 3, reference numeral 1 denotes a base,
2, 3 are device electrodes, 4 is a conductive thin film, 5 is an electron emitting portion,
6, 7 are wirings connected to the device electrodes 2, 3, respectively;
Is an interlayer insulating layer for electrically insulating the wirings 6 and 7 from each other. The wires 6 and 7 may be referred to as a Y-direction wire and an X-direction wire, respectively, in view of the coordinates in FIG. 1, and may be referred to as a lower wire and an upper wire, respectively, depending on the positional relationship with the insulating layer 8.

Hereinafter, the substrate of the present invention will be described in detail. In the present invention, a substrate such as glass having a high softening point is used as the base 1. A glass substrate having a high softening point is a glass substrate having a softening point of 750 ° C. or more, and borosilicate glass, zinc borosilicate glass, aluminosilicate glass,
Aluminoborosilicate glass, barium borosilicate glass, soda barium silicate glass, soda potassium alumina glass, titanium silicate glass and the like are included. However,
The softening point of the above glass changes depending on the composition of the glass, and a composition having a softening point adjusted to be 750 ° C. or higher is used. In addition, as the base, for example, ceramics such as quartz glass and alumina are used.

The materials of the opposing element electrodes 2 and 3 are as follows.
It is preferable to have a stable conductivity even after the subsequent heat treatment step. For example, a metal thin film mainly composed of a noble metal such as Au, Pt, Pd or an alloy thereof is used. It is preferable that the film thickness of the device electrodes 2 and 3 is about several tens of nm, because the device has sufficient conductivity and the step coverage of the conductive thin film 4 is good. In the case where the noble metal thin film is formed on the base 1, sufficient adhesion strength may not be obtained. At this time, a base metal material such as Ti or Cr may be formed as an undercoat to increase the adhesion between the element electrodes 2 and 3 and the base 1.

As the conductive thin film 4, a fine particle film composed of fine particles is preferably used in order to obtain good electron emission characteristics. Since the thermal stability of the conductive thin film 4 is an important parameter that governs the lifetime of the electron emission characteristics, it is desirable to use a material having a higher melting point as the material of the conductive thin film 4. However, in general, the higher the melting point of the conductive thin film 4 is, the more difficult it is to carry out energization forming, which will be described later. Further, the resulting electron-emitting portion may have a problem that the applied voltage (threshold voltage) at which electrons can be emitted increases.

Therefore, the material of the conductive thin film 4 should be selected from those having a moderately high melting point and capable of forming an electron-emitting portion having good electron-emitting characteristics with relatively low forming power. Good.

The thickness of the conductive thin film 4 is set in consideration of the step coverage of the device electrodes 2 and 3, the resistance between the device electrodes 2 and 3, a forming condition described later, and the like. In order to obtain electron emission characteristics, a fine particle film of several nm to several tens nm composed of fine particles of several nm is preferably used.

Under the above-mentioned conditions, PdO can be easily formed into a thin film by baking an organic palladium compound in the air, has relatively low electric conductivity because it is a semiconductor, has low power for forming, and has a high efficiency in forming an electron emitting portion. Alternatively, thereafter, it can be easily reduced to metal palladium, so that the film resistance can be reduced. For example, it can be used as a material suitable for the conductive thin film 4.

The electron emitting portion 5 is a crack formed in a part of the conductive thin film 4, and electrons are emitted from the vicinity of the electron emitting portion 5. The gap may have a large number of conductive fine particles having a particle size of several nm to several tens of nm, that is, a large number of fine particles of PdO or Pd metal generated by reduction of PdO. Depends on the manufacturing method such as the energization processing conditions. The conductive fine particles are similar to some or all of the elements of the material constituting the conductive thin film 4. Further, a part of the electron emitting portion 5 and furthermore, the conductive thin film 4 near the electron emitting portion 5 has carbon or a carbon compound through an activation step described later. With respect to the role of carbon and the carbon compound, it is presumed that the substance constituting the electron-emitting portion 5 controls the electron-emitting characteristics.

The wirings 6 and 7 are for supplying power to a plurality of electron-emitting devices as shown in FIG. .. DXm, n Y-direction wirings 7 are DX1, DX2,.
The directional wiring 6 is composed of DY1, DY2,... DYn (m and n are both positive integers), and each is made of a material and a film thickness such that a substantially uniform voltage is supplied to a large number of electron-emitting devices. , Wiring width, etc. are designed. These m X-direction wirings 7
An interlayer insulating layer 8 is provided between the n-direction wirings 7 and the n-direction wirings 7 and electrically separated to form a matrix wiring.

The shape, material, film thickness, and manufacturing method of the interlayer insulating layer 8 can be appropriately set so as to withstand the potential difference at the intersection of the wiring 6 and the wiring 7. A thick glass layer obtained by printing a glass paste is used.

In the configuration shown in FIG. 1, 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 5 arranged in the X direction is applied to the X-direction wiring 7. The application means is connected, and the Y-direction wiring 6 is connected to a modulation signal generation means (not shown) for modulating each column of the electron-emitting devices arranged in the Y direction according to 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, a large number of electron-emitting devices are arranged, and the electron-emitting devices are arranged in a direction perpendicular to the wiring. 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.

Although various methods are conceivable as a method of manufacturing the electron source substrate of the present invention, an example of the manufacturing process is shown in FIG. Hereinafter, the manufacturing method will be described in order with reference to FIGS. (1) After sufficiently cleaning the glass substrate 1 having a softening point of 750 ° C. or more with a detergent, pure water, and an organic solvent, a device electrode material is deposited by a vacuum evaporation method, a sputtering method, or the like, and the device electrode is formed by a photolithography technique. 2 and 3 are formed (FIG. 4A). The element electrodes 2 and 3 can be formed by applying a printing technique such as offset printing or the like, applying an organometallic paste, and then firing the paste.

(2) Base 1 on which device electrodes 2 and 3 are formed
Next, a pattern of a conductive paste is formed by a screen printing method, and the lower wiring 6 made of metal is formed by baking the pattern of the conductive paste (FIG. 4B).

(3) Further, a desired position on the lower wiring 6,
That is, the interlayer insulating layer 8 is formed at a position intersecting with the upper wiring 7 to be formed in a subsequent step (FIG. 4C). The interlayer insulating layer 8 can also be formed by forming a glass paste pattern by a screen printing method and firing the glass paste pattern. In order to increase the film thickness in order to provide the interlayer insulating layer 8 with sufficient insulating properties,
The above printing and baking can be repeated a desired number of times.

(4) Subsequently, the upper wiring 7 is formed so as to cross on the interlayer insulating layer 8 formed on the lower wiring 6 (FIG. 5D). Similarly to the lower wiring 6, the upper wiring 7 can be formed by forming a pattern of a conductive paste and firing the pattern of the conductive paste.

(5) A film made of an organic palladium compound is formed between the device electrode 2 and the device electrode 3 provided on the substrate 1 by applying and drying a solution of an organic palladium compound. Thereafter, the organic palladium compound film is heated and baked, and is patterned by lift-off, etching, or the like to form a conductive thin film 4 made of PdO fine particles (FIG. 5E). In addition, here, the method of applying the organometallic solution has been described, but is not limited thereto.
It may be formed by a vacuum deposition method, a sputtering method, a CVD method, a dispersion coating method, a dipping method, a spinner method, an inkjet method, or the like.

(6) Subsequently, when an energizing process called forming is performed by applying a pulse-like voltage or a rising voltage from a power supply (not shown) between the element electrodes 2 and 3, ie, between the wirings 6 and 7, An electron emitting portion 5 having a changed structure is formed at the portion of the conductive thin film 4 (FIG. 5F).
This energization treatment locally destroys, deforms, or alters the conductive thin film 4, and emits electrons from the vicinity of the portion where the crack structure is formed.

In the forming process, there are 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. 6A shows a voltage waveform when a pulse having a pulse crest value of a constant voltage is applied. In FIG. 6A, T1 and T2 are the pulse width and pulse interval of the voltage waveform, and T1 is 1 μsec.
c to 10 msec, T2 is 10 μsec to 100 msec
As c, the peak value of the triangular wave (peak voltage at the time of forming) is appropriately selected.

FIG. 6B shows a voltage waveform when a voltage pulse is applied while increasing the pulse peak value. In FIG. 6B, T1 and T2 are the pulse width and pulse interval of the voltage waveform, and T1 is 1 μsec to 10 ms.
ec and T2 are set to 10 μsec to 100 msec, and the peak value (peak voltage at the time of forming) of the triangular wave is increased by, for example, about 0.1 V steps.

In the forming process, a pulse voltage of, for example, about 0.1 V is inserted between the forming pulses so that the conductive thin film 4 is not locally broken or deformed, and the element current is measured. The process ends when the current decreases below a predetermined value.

(7) Next, an activation process is performed on the element for which the forming has been completed. The activation process is performed by applying a pulse voltage in the same manner as the above-described forming process in an atmosphere containing an organic substance. Is obtained by introducing In the case where a vacuum envelope is formed using an electron source substrate as in an image forming apparatus described later, the activation process can be performed by introducing an organic substance into the vacuum envelope.

Suitable organic substances include aliphatic hydrocarbons of alkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, nitriles, phenols, carboxylic acids, 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 or a carbon compound is deposited on the device from organic substances existing in the atmosphere,
The element current If and the emission current Ie change remarkably. The end of the activation step is determined based on the device currents If and / or
Alternatively, the measurement is appropriately performed while measuring the emission current Ie. The pulse width, pulse interval, pulse crest value, and the like are set as appropriate.

Carbon and carbon compounds include, for example, graphite (including so-called HOPG, PG, GC; HO
PG refers to a crystal structure of almost perfect graphite, PG refers to a crystal grain of about 20 nm and has a slightly disordered crystal structure, and GC refers to a crystal grain of about 2 nm and has a further disordered crystal structure. ), Amorphous carbon (refers to amorphous carbon and a mixture of amorphous carbon and the microcrystals of graphite).

(8) The electron source substrate thus manufactured is preferably subjected to a stabilization step. This step is a step of exhausting a residue of the organic substance introduced during the activation treatment. The pressure in the vacuum vessel is preferably 1 to 3 × 10 ⁻⁷ Torr or less, and more preferably 1 × 10 ⁻⁸ Torr or less. It is preferable to use a vacuum exhaust device that does not use oil so that the oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum exhaust device such as a sorption pump or an ion pump can be used. Further, when evacuating the inside of the vacuum vessel, the entire vacuum vessel is heated, and the inner wall of the vacuum vessel,
It is preferable that the organic substance molecules adsorbed on the electron source substrate be easily exhausted. The heating conditions at this time are 80 to 250
C., preferably 150 ° C. or more, it is desirable to carry out the treatment for as long as possible. However, it is not particularly limited to this condition, 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 source substrate.

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 process, 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 a carbon compound can be suppressed, and as a result, the device current If and the emission current I
e becomes stable.

The above is the manufacturing process of the electron source substrate in the present invention. An example in which an image forming apparatus is configured using the electron source substrate will be described below with reference to FIGS. FIG.
Is a basic configuration diagram of the image forming apparatus, and FIG. 8 is a fluorescent film.

In FIG. 7, reference numeral 61 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged; 62, a rear plate on which the electron source substrate 61 is fixed; 67, a fluorescent film 65 on the inner surface of a glass substrate 64;
And a face plate on which a metal back 66 and the like are formed. Reference numeral 63 denotes a support frame. The rear plate 62, the support frame 63, and the face plate 67 are coated with frit glass or the like, and are heated and fired in the air or in nitrogen to seal the envelope 69. 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 69 is composed of the face plate 67, the support frame 63, and the rear plate 62 as described above. However, since the rear plate 62 is provided mainly for reinforcing the strength of the substrate 61, If the substrate itself has sufficient strength, the separate rear plate 62 is unnecessary, and the substrate 6
1, a support frame 63 is directly sealed, and a face plate 67,
The envelope 69 may be constituted by the support frame 63 and the substrate 61.

On the other hand, by providing a support (not shown) called a spacer between the face plate 67 and the rear plate 62, an envelope 69 having sufficient strength against the atmospheric pressure may be formed. it can.

FIG. 8 shows a fluorescent film. The fluorescent film 65 is made of only a phosphor in the case of monochrome, but is made of a black conductive material 71 called a black stripe or a black matrix depending on the arrangement of the phosphor and a phosphor 72 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 of the three primary color phosphors necessary for the color display between the respective phosphors 72 black so that color mixing and the like are 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 phosphor on the glass substrate 64 is not limited to monochrome or color, but a precipitation method, a printing method, or the like is used. A metal back 66 is usually provided on the inner surface side of the fluorescent film 65. The purpose of the metal back is to convert the light emitted from the phosphor toward the inner surface into the face plate 67.
Improving the brightness by specular reflection to the side,
The purpose is to function as an electrode for applying an electron beam acceleration voltage, and to protect the phosphor from damage due to collision of negative ions generated in the envelope. The metal back is
After the formation of the fluorescent film, the inner surface of the fluorescent film may be smoothed (usually called filming), and then Al may be deposited by vacuum evaporation or the like.

The face plate 67 is further provided with a fluorescent film 6.
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 65 in order to increase the conductivity of the phosphor 5. When performing the aforementioned sealing,
In the case of color, since the phosphors of each color must correspond to the electron-emitting devices, it is necessary to perform sufficient alignment. The envelope 69 is connected to a 1 × 1 through an exhaust pipe (not shown).
After the pressure is reduced to about 0 ^-7 Torr, sealing is performed. In addition, getter processing may be performed to maintain the degree of vacuum after sealing the envelope 69. This is because the getter arranged at a predetermined position (not shown) in the envelope 69 is heated by a heating method such as resistance heating or high-frequency heating immediately before or after the envelope 69 is sealed. This is a process for forming a deposited film. The getter is usually composed mainly of Ba or the like.
The vacuum degree of 10 ^-5 or 1 × 10 ^-7 Torr is maintained.

In the image display apparatus of the present invention completed as described above, each electron-emitting device emits electrons by applying a voltage through the external terminals Dox1 to Doxm, Doy1 to Doyn, and emits electrons through the high-voltage terminal 68. An image is displayed by applying a high voltage of several kV or more to the metal back 66 or a transparent electrode (not shown), accelerating the electron beam, colliding the electron beam with the fluorescent film 65, exciting and emitting light.

The configuration described above is a schematic configuration necessary for producing 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.

[0056]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to specific examples, but the present invention is not limited to these examples, and each element within a range in which the object of the present invention is achieved. This also includes those in which substitutions or design changes have been made.

[Embodiment 1] The basic structure of an electron source substrate according to this embodiment is the same as that shown in FIGS.
The method of manufacturing the electron source substrate in this embodiment is shown in FIGS. Hereinafter, the basic configuration and manufacturing method of the image forming apparatus according to the present invention will be described with reference to FIGS. 1, 2, 4, and 5.

FIGS. 4 and 5 show the manufacturing process in the vicinity of one electron-emitting device in an enlarged manner for the sake of simplicity. However, in this embodiment, an electron source substrate in which a large number of electron-emitting devices are arranged in a simple matrix is shown. It is an example.

(Step-a) Pyrex glass (softening point: about 820) which is a kind of borosilicate glass
° C). First, 5 nm thick Ti and 50 nm thick Pt are sequentially deposited on the cleaned substrate 1 by a sputtering method. After that, the pattern of the device electrodes 2 and 3 is formed of photoresist, the Pt / Ti deposition layer other than the pattern of the device electrodes 2 and 3 is removed by dry etching, and finally the photoresist pattern is removed. Form two and three.

(Step-b) On the substrate 1 on which the device electrodes 2 and 3 are formed, a pattern of the wiring 6 is formed by screen printing using an Ag paste, dried, baked at 500 ° C., and made of Ag. The wiring 6 having a desired shape is formed.

(Step-c) Next, a pattern of the interlayer insulating layer 8 is formed by screen printing using a glass paste, dried, and fired at 500 ° C. In order to obtain sufficient insulating properties, printing, drying, and baking of the glass paste are repeated again to form an interlayer insulating layer 8 having a desired shape made of glass.
To form

(Step-d) The pattern of the upper wiring 7 is formed by screen printing using an Ag paste so as to intersect with the lower wiring 6 at the portion where the interlayer insulating layer 8 is formed. To form an upper wiring 7 of a desired shape made of Ag. Through the above steps, a substrate in which the element electrodes 2 and 3 are connected in a matrix by the wirings 6 and 7 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. Through the above steps, the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the device electrodes 2, 3 and the conductive thin film 4 are formed on the base 1.
Was formed to produce an electron source substrate.

Hereinafter, using the electron source substrate of this embodiment,
An example in which the image forming apparatus is configured will be described with reference to FIGS. After fixing the electron source substrate 61 manufactured as described above on the rear plate 62, the
A face plate 67 (formed by forming a fluorescent film 65 and a metal back 66 on the inner surface of a glass substrate 64) is disposed above a support frame 63, and
7. A frit glass was applied to the joint between the support frame 63 and the rear plate 62 and sealed by baking at 380 ° C. for 30 minutes in the air. Also, the electron source substrate 6 on the rear plate 62
1 was also fixed with frit glass.

The fluorescent film 65 is made of only a fluorescent material in the case of monochrome, but in this embodiment, the fluorescent material adopts a stripe shape, a black stripe is formed first, and each color fluorescent material is coated on the electron emission portion. Then, a fluorescent film 65 was manufactured. As the material for the black stripe, a material mainly containing graphite, which is generally used, was used. Glass substrate 6
The slurry method was used to apply the phosphor to the sample No. 4.

A metal back 66 is usually provided on the inner side of the fluorescent film 65. The metal back was prepared by performing a smoothing treatment (usually called filming) on the inner surface of the fluorescent film after the fluorescent film was formed, and then performing vacuum deposition of Al.

The face plate 67 is further provided with a fluorescent film 6.
In some cases, a transparent electrode (not shown) is provided on the outer surface side of the fluorescent film 65 in order to enhance the conductivity of the phosphor layer 5. However, in this embodiment, a sufficient conductivity is obtained only with the metal back, so that the description is omitted. did.

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 sufficient alignment is 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, external terminals Dox1 to Doxm and Doy1 to Doyn. , A voltage was applied between the device electrodes 2 and 3 to form the conductive thin film 4. The voltage waveform of the forming process is the same as that shown in FIG. In this embodiment, T1 is 1 msec,
T2 was set to 10 msec, and performed under 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, the exhaust was continued until the pressure in the panel reached the order of 10 ^-8 Torr, and then the organic substance was injected into the panel from the exhaust pipe of the panel so that the total pressure became 1 × 10 ^-6 Torr. Introduced and maintained. Outer container terminal Dox1 to Do
A pulse voltage having a peak value of 15 V was applied between the device electrodes 2 and 3 through xm and Doy1 to Doyn to perform an activation process. In this manner, the forming and activation processes were performed to form the electron emission portions 5.

Next, the gas was evacuated to a pressure of about 10 ⁻⁶ Torr, and an exhaust pipe (not shown) was welded by heating with a gas burner 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 is provided with an outer container terminal Dox1.
Through Doxm, Doy1 through Doyn, and applying a scanning signal and a modulation signal from a signal generating means (not shown) to emit electrons, thereby causing a high voltage terminal 68 to be emitted.
, A high voltage of 5 kV or more was applied to a metal back 66 or a transparent electrode (not shown) to accelerate the electron beam, collide with the fluorescent film 65, and excite and emit light to display an image.

The image display device of this embodiment was able to display a good image stably over a long period of time at a luminance (about 150 fL) sufficiently satisfactory as a television.

[Embodiment 2] The basic structure of an electron source substrate according to the present embodiment is the same as that of Embodiment 1. (Step-a) On a cleaned soda potassium alumina glass (softening point: about 830 ° C.) substrate 1, 5 nm thick Ti and 50 nm thick Pt are sequentially deposited by sputtering. After that, the pattern of the device electrodes 2 and 3 is formed of photoresist, the Pt / Ti deposition layer other than the pattern of the device electrodes 2 and 3 is removed by dry etching, and finally the photoresist pattern is removed. 2,
Form 3

(Step-b) On the substrate 1 on which the device electrodes 2 and 3 are formed, a pattern of the wiring 6 is formed by screen printing using an Ag paste, dried, baked at 500 ° C., and made of Ag. The wiring 6 having a desired shape is formed.

(Step-c) Next, a pattern of the interlayer insulating layer 8 is formed by screen printing using a glass paste, dried, and fired at 500 ° C. In order to obtain sufficient insulating properties, printing, drying, and baking of the glass paste are repeated again to form an interlayer insulating layer 8 having a desired shape made of glass.
To form

(Step-d) The pattern of the upper wiring 7 is formed by screen printing using an Ag paste so as to intersect with the lower wiring 6 at the portion where the interlayer insulating layer 8 is formed. To form an upper wiring 7 of a desired shape made of Ag. Through the above steps, a substrate in which the element electrodes 2 and 3 are connected in a matrix by the wirings 6 and 7 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. Through the above steps, the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the device electrodes 2, 3 and the conductive thin film 4 are formed on the base 1.
Was formed to produce an electron source substrate.

Thereafter, an image forming apparatus was constructed using the electron source substrate of the present embodiment in the same manner as in the first embodiment. Even in the image display apparatus of the present embodiment, good luminance and satisfactory luminance for a television were obtained. Images could be displayed stably for a long time.

Comparative Example In this comparative example, the same steps as in Examples 1 and 2 were performed, except that soda lime glass having a relatively low softening point was used as the base. (Steps a to e) Using a soda-lime glass substrate (softening point: about 730 ° C.) that has been cleaned, the same process as in Example 4 is performed, and the lower wiring 6, the interlayer insulating layer 8, The upper wiring 7, the element electrodes 2, 3, and the conductive thin film 4 were formed, and an electron source substrate was manufactured.

After sealing was performed in the same manner as in Example 1, the atmosphere in the completed glass container was evacuated with a vacuum pump through an exhaust pipe (not shown). External terminals Dox1 to Doxm and Doy1 to Dox
A voltage was applied between the device electrodes 2 and 3 through yn to form the conductive thin film 4. At this time, there was considerable variation in the voltage value at which forming occurred, and some elements could not be formed.

Thereafter, the entire glass container was heated at 200 ° C. for 10 hours while evacuating with a vacuum pump.
The conductive thin film 4 mainly composed of PdO was not sufficiently thermally reduced.

Next, after exhausting the gas until the pressure in the panel reaches the order of 10 ^-8 Torr, an organic substance is injected into the panel from the exhaust pipe of the panel so that the total pressure becomes 1 × 10 ^-6 Torr. Introduced and maintained. Outer container terminal Dox1 to Do
A pulse voltage having a peak value of 15 V was applied between the device electrodes 2 and 3 through xm and Doy1 to Doyn to perform an activation process. In this manner, the forming and activation processes were performed to form the electron emission portions 5.

After that, similarly to Embodiments 1 and 2, an image forming apparatus was constructed using the electron source substrate of this embodiment.
The image display device of this comparative example had a somewhat dark impression and a rough image due to a large variation.

[0086]

As described above, according to the present invention, a high-performance electron source substrate can be realized by forming an electron source substrate using a glass substrate having a high softening point. Further, a flat screen image forming apparatus having a large screen capable of holding a good image for a long time, for example, a color flat television can be realized by using the apparatus.

[Brief description of the drawings]

FIG. 1 is a plan view showing one example of an electron source substrate of the present invention.

FIG. 2 is a bird's-eye view near the electron-emitting device of the electron source substrate of the present invention.

FIG. 3 is a cross-sectional view of the electron source substrate of the present invention in the vicinity of an electron-emitting device.

FIG. 4 is a diagram for explaining a basic method for manufacturing an electron source substrate according to the present invention.

FIG. 5 is a view for explaining a basic method for manufacturing an electron source substrate according to the present invention.

FIG. 6 is a diagram illustrating an example of a voltage waveform in a forming process 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 is a plan view showing a configuration of a conventional electron source substrate.

FIG. 10 is a bird's-eye view showing a configuration of a conventional electron source substrate.

[Explanation of symbols]

1: substrate, 2: 3: element electrode, 4: conductive thin film, 5: electron emitting portion, 6, 7: wiring, 8: interlayer insulating layer, 61: electron source substrate, 62: rear plate, 63: outer frame , 64: rear plate substrate, 65: fluorescent film, 66: metal back, 6
7: Face plate, 68: High voltage terminal, 69: Vacuum envelope, 71: Black conductor, 72: Phosphor, 81: Electron emitting element, 91: Substrate, 95: Electron emitting section.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Shibata 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Kazuya Miyazaki 3-30-2 Shimomaruko, Ota-ku, Tokyo 5C031 DD09 DD17 5C036 EE03 EF14 EG02 EG12 EG29 EH08 EH21

Claims (6)

[Claims] 1. An electron source substrate comprising: a base; and a plurality of electron-emitting devices provided on the base and having a conductive thin film between a pair of element electrodes, wherein the softening point of the base is 750 ° C.
An electron source substrate characterized by the above. 2. The electron source substrate according to claim 1, wherein said electron-emitting device is a surface conduction electron-emitting device. 3. The electron source substrate according to claim 1, wherein a plurality of said electron-emitting devices are arranged and emit electrons in response to an input signal. 4. The 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 4. The electron source substrate according to item 3. 5. 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 to form an electron-emitting device in a matrix. 5. The electron source substrate according to claim 4, wherein the electron source substrate is arranged in a matrix. 6. 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 1 to 5. Forming equipment.