Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
2001-05-03
2004-11-09
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S496000, C313S497000, C313S310000, C313S309000
Reexamination Certificate
active
06815884
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electron source forming substrate used in forming an electron source and to the electron source and an image forming apparatus using the substrate.
2. Related Background Art
Heretofore in the past, there have been known electron-emitting devices, which are broadly classified into two types using thermionic electron-emitting devices and cold cathode electron-emitting devices. For the cold cathode electron-emitting devices, there are available field emission type (hereinafter referred to as “FE type”),metal/insulating layer/metal type (hereinafter referred to as “MIM type”), surface conduction type electron-emitting device and the like.
As an example of the FE type, there are known those devices as disclosed in W. P. Dyke & W. W. Dolan, “Field emission”, Advance in Electron Physics, 8.89 (1956) or C. A. Spindt. “Physical properties of Thin-Film Field Emission Cathodes with Molybdenium Cones”, J. Appl. Phys., 47,5248 (1976) and the like.
As an example of the surface conduction type electron-emitting device type, there are known those as disclosed in M. I. Elinson, Recio Eng. Electron Phys., 10,1290 (1965) and the like.
The surface conduction type electron-emitting device utilizes a phenomenon where electron emission occurs by letting current flow in parallel with a film surface on a thin film of a small area formed on a substrate. For the surface conduction type electron-emitting device, there are reported those which use SnO
2
thin film by the above described Elinson and the like, Au thin film “G. Dittmer: “Thin solid Films”, 9, 317 (1972)”, In
2
O
3
/SnO
2
thin film “M. Hartwell and C. G. Fonstad: “IEEE Trans. ED Conf.” 519 (1975)”, carbon thin film “Hisashi Araki et. al: SHINNKUU Vol.26, No. 1, 22 pages (1983)” and the like.
To utilize the above described electron-emitting device by holding an electron source arranged and constructed on a substrate inside an envelope which is kept vacuum inside, it is necessary to connect the electron source to the envelope and other members. This connection is usually performed by heating and fusion by using frit glass. The heating temperature at this time is typically approximately 400° C. to 500° C. and the time thereof is typically approximately ten minutes to one hour, which differs depending on the size of the envelope.
For the material of the envelope, in view of simplicity and reliability of the connection by frit glass and relatively inexpensive cost, soda lime glass is preferably used. Also, because a high strain point glass where a strain point is raised by replacing a part of Na by K is easy for frit connection, it can be preferably used as well. Also, with regard to the material of the substrate of the above described electron source, in view of reliability of the connection to the envelope, similarly the soda lime glass or the above described high strain point glass is preferably used.
The above described soda lime glass contains alkali element metal as its component and particularly contains the large volume of Na as Na
2
O. Na element is easy to diffuse by heat and, therefore, when exposed to high temperatures during a processing, Na is sometimes diffused into each type of members formed on the soda lime glass, particularly into the member constituting the electron-emitting device, thereby deteriorating its characteristics.
It was reveled that the above described influence by Na sometimes occurs, but to a lessened degree, by that much if Na content is small when the above described high strain point glass is used as the substrate of the electron source.
As means for reducing the above described influence of Na, for example, there are disclosed in Japanese Patent Application Laid-Open No. 10-241550, EP-A-850892 an electron source forming substrate where the concentration of Na of the surface area of the side where the electron-emitting device of the substrate containing Na is at least arranged is smaller than that of other area and also an electron source forming substrate having a phosphorus containing layer.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide at a low cost an electron source forming substrate where time changes in the electron-emitting characteristics of the electron-emitting device is reduced, and to provide the electron source as well as an image display apparatus using the substrate.
The present invention provides the electron source forming substrate where the electron emitting device are arranged, comprising a substrate and an insulating material film which is disposed on the surface of the substrate, at which surface the above described electron-emitting device of the above described substrate is arranged, and contains a plurality of metallic oxide particles having an average particle size within the range of 6 nm to 60 nm as expressed in a median value.
Also, the present invention provides the electron source forming substrate where the electron emitting device are arranged, comprising a substrate and an SiO
2
film which is disposed on the surface where the above described electron-emitting device of the above described substrate is arranged, and which contains a plurality of metallic oxide particles having an average particle size within the range of 6 nm to 60 nm as expressed in the median value.
Also, the present invention provides the electron source, comprising the substrate and the electron-emitting device arranged on the above described substrate, wherein the above described substrate is any of the above described electron source forming substrates.
Also, the present invention provides the image display apparatus comprising an envelope and an image display member for displaying images by irradiation of the electron from an electron-emitting device and the above described electron-emitting device, wherein the substrate where the above described electron-emitting devices are arranged is any of the above described electron source forming substrates.
The electron source forming substrate of the present invention is an electron source forming substrate wherein the electron-emitting device is arranged, comprising the substrate and the insulating material film which is disposed on the surface where the above described electron-emitting device of the above described substrate is arranged, and which contains a plurality of metallic oxide particles having an average particle size within the range of 6 nm to 60 nm as expressed in the median value.
In the above described electron source forming substrate of the present invention, as still further preferable embodiments,
the above described insulating material film further contains phosphorus,
the above described insulating material film further contains phosphorus having 1 weight portion to 10 weight portions,
the thickness of the above described insulating material film is within the range of 200 nm to 600 nm,
the thickness of the above described insulating material film is within the range of 300 nm to 400 nm, on the above described insulating material film, a film comprising the insulating material is laminated,
the thickness of the film comprising the above described insulating material is within the range of 20 nm to 150 nm, and
the thickness of the film comprising the above described insulating material is within the range of 40 nm to 100 nm.
Also, the electron source forming substrate of the present invention is an electron source forming substrate where the electron-emitting device is arranged, comprising the substrate and the SiO
2
film which is disposed on the surface where the above described electron-emitting device of the above described substrate is arranged, and contains a plurality of metallic oxide particles having an average particle size within the range of 6 nm to 60 nm as expressed in the medial value.
In the above described electron source forming substrate, as still further preferable embodiment:
the above described SiO
2
further contains phosphorus,
the above described SiO
2
further contains phosphorus having one w
Ishiwata Kazuya
Meguro Tadayasu
Yamada Shuji
Patel Vip
Perry Anthony
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