Electric lamp or space discharge component or device manufacturi – Process – Electrode making
Reexamination Certificate
1997-04-28
2002-01-01
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
Electrode making
C445S006000, C427S078000
Reexamination Certificate
active
06334803
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of manufacturing an electron-emitting device, a method of manufacturing an electron source and a method of manufacturing an image-forming apparatus comprising such an electron source.
2. Related Background Art
There have been known two types of electron-emitting device; the thermoelectron emission type and the cold cathode electron emission type. Of these, the cold cathode emission type refers to devices including field emission type (hereinafter referred to as the FE type) devices, metal/insulation layer/metal type (hereinafter referred to as the MIM type) electron-emitting devices and surface conduction electron-emitting devices.
Examples of FE type device include those proposed by W. P. Dyke & W. W. Dolan, “Field emission”, Advances in Electron Physics, 8, 89 (1956) and C. A. Spindt, “Physical Properties of thin-film field emission cathodes with molybdenum cones”, J. Appl. Phys., 47, 5248 (1976).
Examples of MIM device are disclosed in papers including C. A. Mead, “Operation of Tunnel-Emission Devices”, J. Appl. Phys., 32, 646 (1961).
Examples of surface conduction electron-emitting device include one proposed by M. I. Elinson, Radio Eng. Electron Phys., 10 (1965).
Known image-forming apparatus utilizing cold cathode type electron-emitting devices include flat type electron beam display panels realized by arranging an electron source substrate carrying thereon a large number of electron-emitting devices and an anode substrate provided with a transparent electrode and a fluorescent body vis-a-vis and in parallel with each other within an envelope and evacuating the envelope.
I. Brodie, “Advanced technology: flat cold-cathode CRT's”, Information Display, 1/89, 17 (1989) describes an image-forming apparatus comprising field emission type electron-emitting devices.
On the other hand, Japanese Patent Application Laid-Open No. 7-235255 discloses an image-forming apparatus comprising surface conduction electron-emitting devices.
When compared with currently popular cathode ray tubes (CRTs), flat type electron beam display panels are more adapted for light weight and large screen image-forming apparatus. They can provide bright and high quality images than other known flat type display panels including those utilizing liquid crystal, plasma display panels and electroluminescent display panels.
Now, a known surface conduction electron-emitting device and a method of manufacturing such a device as well as a display panel comprising such devices and a method of manufacturing the same as disclosed in the above cited Japanese Patent Application Laid-Open No. 7-235255 will be briefly summarized below.
FIG. 18
of the accompanying drawings schematically illustrates a surface conduction electron-emitting device of the type under consideration. Referring to
FIG. 18
, it comprises a substrate
1
, a pair of device electrodes
2
and
3
and an electroconductive thin film
4
, which thin film is typically a palladium thin film formed by baking a film of an organic palladium compound. An electron-emitting region
5
will be produced therein when subjected to a current conduction process referred to as energization forming, which will be described hereinafter.
Conventionally, the electroconductive thin film
4
of a surface conduction electron-emitting device is subjected to energization forming in order to produce an electron-emitting region
5
before the device is put to use for electron emission. In an energization forming process, a constant DC voltage or a slowly rising DC voltage that rises very slowly typically at a rate of 1 V/min. is applied to given opposite ends of the electroconductive film
4
to partly destroy, deform or transform the film and produce an electron-emitting region
5
which is electrically highly resistive. Thus, the electron-emitting region
5
is part of the electroconductive film
4
that typically contains a fissure or fissures therein so that electrons may be emitted from the area including the fissure(s) and its vicinity. Note that, once subjected to an energization forming process, a surface conduction electron-emitting device comes to emit electrons from its electron emitting region
5
whenever an appropriate voltage is applied to the electroconductive film
4
to make an electric current run through the device.
After the energization forming process, the device is preferably subjected to an activation process, which is a process for remarkably changing the device current If and the emission current Ie of the device.
An activation process is typically conducted by repetitively applying an appropriate pulse voltage to the electron-emitting region in an atmosphere containing gaseous organic substances. As a result of this process, carbon or a carbon compound arising from the organic substances contained in the atmosphere is deposited on the device to remarkably change the device current If and the emission current Ie.
On the other hand, a display panel to be used for an image-forming apparatus can be prepared by placing an electron source substrate carrying thereon a large number of electron-emitting devices that are arranged in the form of a matrix or parallel ladders and a face plate provided with a fluorescent body adapted to emit light when irradiated with electrons emitted from the electron source substrate and, if necessary, a control electrode vis-a-vis and in parallel with each other within a vacuum envelope.
FIG. 19
of the accompanying drawings schematically illustrates a display panel comprising an electron source realized by arranging surface conduction electron-emitting devices in the form of a matrix. In
FIG. 19
, the electron source comprises an electron source substrate
201
carrying thereon a plurality of electron-emitting devices, a rear plate
202
rigidly holding the electron source substrate
201
and a face plate
203
realized by arranging a fluorescent film
204
and a metal back
205
on the inner surface of a glass substrate. Reference numeral
206
denotes a support frame to which the rear plate
202
and the face plate
203
are bonded by means of frit glass. Reference numeral
207
denotes a vacuum envelope provided with terminals Dox
1
through Doxm and Doy
1
through Doyn arranged in correspondence to the matrix of wires in the electron source and a high voltage terminal
208
.
A display panel as described above can be made to emit electrons from selected electron-emitting devices arranged on the electron source substrate in a simple matrix arrangement by selectively applying a drive pulse voltage to them. A DC voltage as high as 1 to 10kV is applied to the high voltage terminal
208
in order to satisfactorily energize the fluorescent body relative to the electron beams emitted from the devices.
An image-forming apparatus capable of displaying highly bright images with high quality can be realized by combining a display panel comprising surface conduction electron-emitting devices and an appropriate drive circuit in a manner as described above.
As discussed above, with any typical known method of manufacturing a surface conduction electron-emitting device, an electron-emitting region
5
is normally produced by subjecting the electroconductive thin film
4
to an energization forming process. This process consumes a considerable amount of electricity for electrically energizing the electroconductive thin film. When preparing a large number of surface conduction electron-emitting devices on a common substrate, it is preferable that a relatively large number of them are subjected to energization forming simultaneously in a single operation (for example, on a row by row basis) but the number may inevitably be limited if each device consumes a considerable amount of electricity for energization forming. This problem has so far been avoided by reducing the thickness of the electroconductive thin film
4
and/or by using a film comprising fine particles for the electroconductive thin film
4
in order to reduce the power consumption rat
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Ramsey Kenneth J.
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