Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
2000-02-25
2004-12-14
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S310000, C313S311000, C313S496000, C313S497000, C257S086000, C252S519400
Reexamination Certificate
active
06831401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electron emitting device, an electron source constituted by this electron emitting device and an image-forming apparatus which is an application thereof, and more particularly to a surface conduction electron-emitting device having a novel structure, an electron source using this device and an image-forming apparatus such as a display unit which is an application thereof.
2. Related Background Art
A surface conduction electron-emitting device utilizes such a phenomenon as that electron emission is generated by flowing an electric current through an electroconductive thin film formed on a substrate.
As an example of this surface conduction electron-emitting device, there are reported a device using an SnO
2
thin film [M. I. Elinson Radio Eng. Electron Phys., 10, 1290, (1965)], a device using an Au thin film [G. Ditmmer, Thin Solid Films, 9,317 (1972)], a device using an In
2
O
3
/SnO
2
thin film [M. Hartwell and C. G. Fonsted, IEEE Trans. ED Conf., 519 (1975)], a device using a carbon thin film [Hisashi Araki and et al: SHINKU (Vacuum), Vol. 26, No. 1, p. 22 (1983)] and others.
In these surface conduction electron-emitting devices, it is general to cause electron emission by performing an energization operation called “forming” with respect to the electroconductive film before carrying out electron emission.
Here, “forming” means that a fixed voltage or a voltage which slowly rises at a rate of, e.g., approximately lV/min to both ends of the electroconductive film and an electric current is caused to flow through the electroconductive film so that the electroconductive film is locally fractured, deformed or transformed to have an electrically high resistance, thereby generating electron emission.
A fissure is formed on a part of the electroconductive film with this operation, and it can be considered that the phenomenon of electron emission occurs due to existence of this fissure. Although a position where the actual electron emission occurs is not completely cleared, the fissure and the surrounding area thereof may be referred to as “an electron-emitting region” for the sake of convenience.
The present applicant has advanced many suggestions concerning the surface conduction electron-emitting device. For example, in regard to the above- described “forming”, Japanese patent No. 2854385, U.S. Pat. Nos. 5,470,265, and 5,578,897 disclose that forming is preferably carried out by application of a pulse voltage to the electroconductive film.
Here, a waveform of the pulse voltage can be appropriately selected by any of a method for maintaining a wave height value constant such as shown in
FIG. 5A and a
method for gradually increasing the wave height value such as shown in
FIG. 5B
, taking into account a shape or form of the device and a condition for forming.
Further, it has been discovered that an electric current flowing through the device (device current If) and an electric current involved by electron emission (emission current Ie) are both increased by repeatedly applying the pulse voltage to the electron-emitting device in an atmosphere containing an organic substance after the above-described forming, and this process is referred to as “an activation operation”.
This operation forms a deposition containing carbon as a main component in an area including a fissure formed on the electroconductive film by “forming”, and its detail is disclosed in Japanese Patent Application Laid-Open No. 7-235255.
When the above-described surface conduction electron-emitting device is applied to the image-forming apparatus and the like, low-consumption power and high brightness are further required.
Therefore, as a performance of the electron-emitting device, a ratio of the emission current Ie to the device current If, i.e., the electron-emitting efficiency needs to be higher than that of the prior art.
In order to improve such a performance, it is naturally necessary that a variation in the performance with time due to continuation of the electron emission is not larger than that in the prior art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an electron-emitting device superior in an electron-emitting characteristic, an electron source using this device and an image-forming apparatus using this electron source.
The present invention provides an electron-emitting device comprising: a pair of conductors opposed to each other on a substrate; and a pair of deposition films containing carbon as a main component which are respectively connected to the pair of conductors and disposed with a gap therebetween, wherein the deposition film contains sulfur in a range of not less than 1 mol % and not more than 5 mol % as a ratio to the carbon.
Further, the present invention provides an electron-emitting device comprising: a pair of device electrodes opposed to each other on a substrate; an electroconductive film which is connected to the pair of device electrodes and has a fissure between the pair of device electrodes; and a deposition which is formed inside the fissure and on an area including the fissure and has a gap whose width is narrower than the fissure inside the fissure and carbon as a main component, wherein the deposition contains sulfur in a range of not less than 1 mol % and not more than 5 mol % as a ratio to the carbon.
REFERENCES:
patent: 4766477 (1988-08-01), Nakagawa et al.
patent: 5196366 (1993-03-01), Yamazaki et al.
patent: 5470265 (1995-11-01), Nomura et al.
patent: 5578897 (1996-11-01), Nomura et al.
patent: 5728435 (1998-03-01), Geis et al.
patent: 5986389 (1999-11-01), Tsukamoto
patent: 6169356 (2001-01-01), Ohnishi et al.
patent: 6208071 (2001-03-01), Nishimura et al.
patent: 6410144 (2002-06-01), Dearnaley et al.
patent: 0 660 357 (1995-06-01), None
patent: 7-235255 (1995-09-01), None
patent: 07-235255 (1995-09-01), None
patent: 08-273523 (1996-10-01), None
patent: 2854385 (1998-11-01), None
patent: 2000-285789 (2000-10-01), None
patent: 2001-148222 (2001-05-01), None
M.I. Elinson et al., “The Emission of Hot Electrons and The Field Emission of Electrons From Tin Oxide”, Radio Engineering and Electronic Physics, Jul. 1965, pp. 1290-1296.
M. Hartwell, “Strong Electron Emission From Patterned Tin-Indium Oxide Thin Films”, IEDM, 1975, pp. 519-521.
H. Araki, “Electroforming and Electron Emission of Carbon Thin Films”, Journal of the Vacuum, Society of Japan, 1983, pp. 22-29 (with English Abstract on p. 22).
G. Dittmer, “Electrical Conduction and Electron Emission of Discontinuous Thin Films”, Thin Solid Films, 9, 1972, pp. 317-328.
Hamamoto Yasuhiro
Tamura Miki
Yamamoto Keisuke
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Hodges Matt
Patel Vip
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