Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
1999-02-11
2003-06-17
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C427S010000
Reexamination Certificate
active
06579139
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for forming a plurality of films, a method for fabricating an electron emitting element that employs those films, and a method for manufacturing an image forming apparatus that employs the electron emitting element.
2. Related Background Art
Conventionally, electron emitting elements are sorted into two types: a thermoelectron emitting element and a cold-cathode electron emitting element. The cold-cathode electron emitting element includes a field-effect emitting type (hereinafter referred to as an “FE type”), a metal/insulating layer/metal type (hereinafter referred to as an “MIM type”) and a surface conductive type. A well known electron emitting element of the FE type is disclosed in, for example, “Field Emission,” W. P. Dyke & W. W. Doran, Advance in Electron Physics, 8, 89 (1956) or “Physical Properties of Thin-film field Emission Cathodes with Molybdeniumcones,” C. A. Spindt, J. Appl. Phys., 47, 5248 (1976).
A well known electron emitting element of the MIM type is disclosed in, for example, “Operation of Tunnel-Emission Devices,” C. A. Mead, J. Appl. Phys., 32, 646 (1961).
A well known electron emitting element of a surface conductive type is disclosed in, for example, Radio Eng. Electron Phys., 10, 1290 (1965) by M. I. Elinson.
The electron emitting element of a surface conductive type supplies a current to a thin film, which is formed on a small area of a substrate that is parallel to the surface of the film, that emits electrons. Such electron emitting elements of a surface conductive type are the one disclosed above by Elinson that employs SnO
2
thin film, one that employs Au thin film (Thin Solid Films, 9, 317 (1972), G. Dittmer), one that employs In
2
O
3
/SnO
2
(IEEE Trans. ED Conf., 519 (1975), M. Hartwell and C. G. Fonstad), and one that employs a thin carbon film (Vacuum, Vol. 26, 1, page 22 (1983), Hisashi Araki, et al.).
In
FIG. 17
is shown the arrangement of the element disclosed by M. Hartwell as a specific example of an electron emitting element of a surface conductive type. In
FIG. 17
, a substrate
1
and element electrodes
2
and
3
are provided for the emitting element. A thin conductive film
4
is a thin metal oxide film having a H-shaped pattern that is formed by sputtering, and an electron emitting portion
5
that is formed by an electrification process that is called electroforming, which will be described later. In
FIG. 17
, interval L between the element electrodes is set to 0.5 to 1 mm, and distance W′ is set to 0.1 mm. The location and the shape of the electron emitting portion
5
are not fixed, and are specifically represented.
Generally, in a conventional electron emitting element of a surface conductive type, before the emission of electrons the electrification process called electroforming is performed for the thin conducive film
4
, and the electron emitting portion
5
is formed. That is, the electroforming is the formation of the electron emitting portion by an electrification process. For example, a direct current voltage or a very gradually boosting voltage, such as 1 V/min., is applied to both ends of the thin conductive film
4
to locally destroy, or deform or degenerate the film
4
, and the electron emitting portion
5
that electrically is highly resistant is formed. The electron emitting portion
5
emits electrons in the vicinity of a crack that occurs in one part of the thin conductive film
4
. The electron emitting element for which the electroforming process has been performed applies a voltage to the thin conductive film
4
and permits the emission of electrons by the electron emitting portion
5
.
Since the electron emitting element of a surface conduction type is easy to both form and arrange, multiple elements of this type can be formed and arranged in a large area. Therefore, various applications are being studied to determine the effective use of this characteristic. A load beam source and an image display device are examples of such applications.
In
FIG. 18
is shown the arrangement of an electron emitting element disclosed in Japanese Patent Application Laid-Open No. 2-56822. In
FIG. 18
, the electron emitting element comprises: a substrate
1
, element electrodes
2
and
3
, a thin conductive film
4
, and an electron emitting portion
5
. Various methods are available for fabricating the substrate of the electron emitting element. For example, an ordinary vacuum deposition technique or photolithography technique is employed to form the element electrodes
2
and
3
on the substrate
1
. Then, the thin conductive film
4
is formed by a dispersive coating method, following which a voltage is applied to the element electrodes
2
and
3
, to electrify them and to form the electron emitting portion
5
.
In addition, a further example is an electron source wherein multiple electron emitting elements of a surface conductive type are arranged in parallel to form multiple rows, and both ends (both of the element electrodes) of each electron emitting element are terminated by a wiring (also called a common wiring) e.g., Japanese Patent Application Laid-Open No. 64-1332, No. 1-283749 and No. 2-257552).
An example display device is proposed that can be fabricated so that it is as flat as a liquid crystal display device, but that is self-emitting and does not require a backlight. Such a display device comprises an electron source, wherein multiple electron emitting elements of a surface conductive type are arranged, and a fluophor that emits visible light upon irradiation with an electron beam originating at the electron source (U.S. Pat. No. 5,066,883).
The present inventor proposed a method, for fabricating an electron emitting element of a surface conductive type, that is advantageous for the formation of a conductive film to cover a large area, without resorting to the use of the vacuum sputtering method or the vacuum deposition method. According to another example method, an organic metal content solution is spinner-coated onto the substrate, and the film is patterned into a desired shape and is thermally cracked to form a conductive film. In addition, in Japanese Patent Application Laid-Open No. 8-171850 a method is proposed whereby, at a step in the patterning of a conductive film to provide a desired shape, droplets of an organic metal content solution are applied to the substrate using an ink-jet method, such as the bubble-jet method or the piezo-jet method, instead of the photolithography method, and a conductive film having a desired shape is formed.
According to the conventional ink-jet method described in Japanese Patent Application Laid-Open No. 8-171850, when wirings, an insulating layer and element electrodes can be fabricated as designed to form the substrate, the locations whereat it is determined the electron emitting portions are to be formed are arranged at intervals relative to a reference position on the electron source substrate. Therefore, when liquid droplets are ejected at a constant cyclic rate, as designed, they can be easily applied to the electron source substrate. However, in actuality, the widths and locations of the wirings and the insulating layer fabricated in or between the substrates by screen printing may vary. Thus, if the liquid droplets are applied as designed, when they contact the insulating layer and wirings they are absorbed, and no electron source is formed. Because of this defect, the resultant substrate can not fully satisfy the requirements for an electron source substrate.
SUMMARY OF THE INVENTION
According to the present invention, an innovative film formation method is provided. In particular, a method for accurately and efficiently forming a film is provided.
A film formation method according to one aspect of the present invention follows.
A method for forming a film locally on a substrate comprises the steps of:
detecting the state of the substrate;
employing the obtained result to calculate positional information concerning a plurality of locations at
Hasegawa Mitsutoshi
Mishima Seiji
Sando Kazuhiro
Shigeoka Kazuya
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Ramsey Kenneth J.
LandOfFree
Film formation method, method for fabricating electron... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Film formation method, method for fabricating electron..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Film formation method, method for fabricating electron... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3114027