Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
1999-06-30
2004-08-17
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S292000
Reexamination Certificate
active
06777868
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
An invention set forth in this application relates to a film capable of moderating electrification. An invention set forth in this application relates in particular to a film capable of moderating influences due to electrification which may be produced by bombardment of electrons. An invention set forth in this application relates to an electron beam system. An invention set forth in this application relates to member which is used in the electron beam system, An invention set forth in this application relates to an image forming system. Furthermore, an invention set forth in this application relates to methods to manufacture the film, systems and the member.
2. Related Background Art
Planar surface type displays which have small depths, occupy small spaces, and are light in weights thereof are attracting attentions as substitutes for cathode-ray tube type displays. Under the present circumstances, the planar surface type displays are classified into a liquid crystal type, plasma luminescence type and display using multiple electron sources. The plasma luminescence type and multi-electron source type displays have large angles of view and are capable of displaying images of qualities as high as those displayed by the cathode-ray tube type displays.
A display which uses a large number of fine electron sources is schematically shown in
FIG. 14
, wherein a reference numeral
51
represents an electron source which is disposed on a rear plate
52
made of glass and a reference numeral
54
designates a face plate which is made of glass coated with a fluorescent substance. There have been developed for electron sources, a field-emission type electron emission element which can be integrated at a high density and emit electrons from a conical or needle-like tip and a cold-cathode ray tube type electron emission element such as a surface conductive type electron emission element. A wiring to drive the electron source is omitted in FIG.
14
. In order to prevent a substrate from being deformed due to a difference between internal vacuum and an external atmospheric pressure as the display has a larger display area, it is necessary to thicken the rear plate and the face plate. However, the rear plate and the face plate which are thick not only increase a weight of the display but also allow an image to be distorted when it is seen obliquely. Accordingly, a spacer or a structure support which is referred to as a rib is used between the rear plate and the face plate so that the display is bearable of the atmospheric pressure with relatively thin glass plates. The rear plate on which the electron source is formed and the face plate on which the fluorescent substance is coated are kept at a distance ordinarily of a submillimeter to several millimeters and an interior of the display is kept at a high vacuum as described above.
To accelerate electrons emitted from the electron source, a high voltage not lower than several hundred volts is applied to an anode electrode (metal back) (not shown) between the electron source and the fluorescent substance. Since a magnetic field which exceeds 1 kV/mm in electric field intensity is applied across the fluorescent substance and the electron source, it is feared that electricity may be discharged from the spacer. Furthermore, the spacer is electrified by some of electrons which are emitted from the electron source disposed nearby and bombard the spacer or positive ions which are produced by the emitted electrons and adhere to the spacer. The electrification of the spacer deflects the electrons emitted from the electron source from their due loci and makes the electrons reach positions different from regular positions on the fluorescent substance, whereby an image in the vicinity of the spacer is distorted when it is seen through a front glass plate.
In order to solve this problem, there has been proposed to cancel the electrification by flowing a weak current to the spacer (Japanese Patent Application Laid-Open Nos. 57-118355 and 61-124031). According to this proposal, a thin high resistance film is formed on a surface of an insulating spacer so that a low current runs through a surface of the spacer. An electrification moderating film used for this purpose is a thin mixed crystal film or a metal film which is made of tin oxide or tin oxide and indium oxide.
Since the conventionally used thin film which is made of tin oxide or the like mentioned above is so sensible of gases such as oxygen as it is applied to gas sensors, its resistance is liable to be varied by atmosphere. Furthermore, since these materials and metal films have low specific resistance, it is necessary for obtaining high resistance to form the films in an island-like pattern or extremely thin.
SUMMARY OF THE INVENTION
A primary object of an invention set forth in this application is to provide an electrification moderating film which realizes at least either of preferable suppression of electrification and preferable reduction of electrification, thereby moderating influences due to electrification. The present application includes also an invention which has an object to provide at least any of a highly reproducible film, a stable film and a film having a resistance value hardly varying at a heating step. The present application further includes an invention which has an object to provide a member of an electron beam system, a spacer in particular, which is capable of moderating influences due to electrification. Furthermore, the present application also includes an invention which has an object to provide an electron beam system, an image forming system in particular, which uses such a member.
An electrification moderating film according to one of the inventions set forth in the present application is configured as:
an electrification moderating film characterized by containing at least a germanium compound.
This film is capable of suppressing influences which are produced by electrification.
The germanium compound may be a nitride of germanium or an oxide of germanium.
Furthermore, it is preferable that the germanium compound is a nitride which contains a transition metal and germanium. It is preferable in particular that the transition metal is at least one of chromium, titanium, molybdenum, tantalum and tungsten.
Furthermore, it is preferable that the germanium compound is a nitride which contains a transition metal, aluminium and germanium, and that the transition metal is at least one of chromium, titanium, tantalum, molybdenum and tungsten.
Furthermore, it is preferable that the germanium compound is a nitride of germanium and that germanium of the electrification moderating film is nitrided at a ratio not lower than 50%.
Furthermore, it is preferable that the germanium compound is a nitride which contains a transition metal and germanium and, that germanium of the electrification moderating film is nitrided at a ratio not lower than 50%.
Furthermore, it is preferable that the germanium compound is a nitride which contains a transition metal, aluminium and germanium, and that aluminium of the electrification moderating film has a surface nitrization ratio not lower than 35%. The surface nitrization ratio of aluminium is a quotient of an atomic concentration of nitrogen composing aluminium nitride by an atomic concentration of aluminium.
Furthermore, the electrification moderating film may be formed so as to contain a second layer which contains at least the germanium compound and a first layer which contains at least a metal. The second layer may be insulated.
In this case, the metal is preferably a transition metal. It is preferable that the metal is at least one of iron, cobalt, copper and ruthenium.
Furthermore, it is preferable that the first layer contains at least an oxide of the metal. It is preferable in particular that the first layer contains at least one of iron oxide, cobalt oxide, copper oxide and ruthenium oxide. The first layer may contain a mixture of these metals.
Furthermore, it is preferable that the lay
Kosaka Yoko
Ohguri Noriaki
Okamura Yoshimasa
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Patel Vip
Williams Joseph
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