Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
1998-05-08
2001-04-24
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C445S051000
Reexamination Certificate
active
06220912
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing an electron source having electron emitting portions. The present invention also relates to an electron source produced by the producing method thereof, an image forming apparatus using the electron source, and an apparatus for producing the electron source.
2. Related Background Art
The electron emitting elements conventionally known are roughly classified under two types using thermionic emission elements and cold emission elements. Examples of the cold emission elements are electron emitting elements of a field emission type (hereinafter referred to as “FE type”), a metal/insulator/metal type (hereinafter referred to as “MIM type”), a surface conduction type, and so on. Examples of the FE type known are those disclosed in W. P. Dyke & W. W. Doran, “Field Emission,” Advance in Electron Physics, 8, 89 (1956), C. A. Spindt, “Physical Properties of thin-film field emission cathodes with molybdenum cones,” J. Appl. Phys., 47, 5248 (1976), and so on. An example of the MIM type known is the one as disclosed in C. A. Mead, “Operation of Tunnel-Emission Devices,” J. Appl. Phys., 32, 646 (1961), for example.
An example of the surface conduction type electron emitting element is the one as disclosed in M. I. Elinson, Radio Eng. Electron Phys., 10, 1290 (1965), for example.
The surface conduction type electron emitting element emits electrons when a current is allowed to flow in parallel to the film plane through a thin film of a small area formed on a substrate. There are reports on this surface conduction type electron emitting element; for example, those using Au thin film [G. Dittmer: Thin Solid Films, 9, 317 (1972)], using In
2
O
3
/SnO
2
thin film [M. Hartwell and C. G. Fonstad: IEEE Trans. ED Conf., 519 (1975)], using carbon thin film [Hisashi Araki et al.: Vacuum, Vol 26, No. 1, p 22 (1983)], and so on.
FIG. 16
schematically shows the element configuration of M. Hartwell, as described above, as a typical example of these surface conduction type electron emitting elements. In the same figure reference numeral
1
designates a substrate. Numeral
4
represents a conductive thin film, which is, for example, a thin film of metal oxide formed in a pattern of H-shape by sputtering. An electron emitting section
5
is formed by an electrification process called “energization forming” as detailed hereinafter. The distance L1 between the element electrodes in the drawing is set to 0.5 to 1 mm and the width W′ to 0.1 mm. Since the position and shape of the electron emitting section
5
are not described specifically, the element is illustrated as a schematic view.
In these conventional surface conduction type electron emitting elements, the electron emitting section
5
is formed generally by preliminarily subjecting the conductive thin film
4
to the electrification process called the energization forming prior to emission of electron. The energization forming is formation of the electron emitting section by electrification, which is achieved, for example, by applying a do voltage or very slowly increasing voltages to the both ends of the conductive thin film
4
to effect electrification, so as to locally break, deform, or alter the conductive thin film, thereby forming the electron emitting section
5
kept in an electrically high resistance state. The electron emitting section
5
has a crack produced in a part of the conductive thin film
4
and emits electrons from near the crack. The surface conduction type electron emitting element processed by the aforementioned energization forming process emits electrons from the above-stated electron emitting section
5
when the voltage is applied to the conductive thin film
4
to allow the current to flow through the element.
The surface conduction type electron emitting elements described above have the advantage that a lot of surface conduction type emitting elements can be arrayed over a large area, because the structure is simple and they can be produced using the conventional semiconductor fabrication technology. There are researches on such various applications as to make use of this feature. Examples of the applications are image forming apparatus such as charged electron beam sources and display devices.
FIG. 15
shows the structure of the electron emitting element disclosed in the official gazette of Japanese Laid-open Patent Application No. 2-56822 filed by Applicant. In the same figure, numeral
1
denotes a substrate,
2
and
3
element electrodes,
4
a conductive thin film, and
5
an electron emitting section. There are a variety of methods for producing this electron emitting element. For example, the element electrodes
2
and
3
are formed on the substrate
1
by the vacuum thin film technology and photolithography etching technology in the ordinary semiconductor processes. Then the conductive thin film
4
is formed by a dispersion coating method such as spin coating, or the like. After that, the voltage is applied to the element electrodes
2
,
3
to carry out the electrification process, thereby forming the electron emitting section
5
.
This production method in the conventional example has drawbacks that large-scale photolithography etching facilities are necessary and indispensable for forming the elements over a large area, the number of steps is also large, and the production cost is thus high. In view of these drawbacks, there are proposals on methods for forming the conductive thin film of the surface conduction type electron emitting element by directly dispensing droplets of a solution containing a metal element for the conductive thin film by the ink jet method (for example, as disclosed in Japanese Laid-open Patent Application No. 8-171850).
Since the conventional ink jet method as described in the official gazette of Japanese Laid-open Patent Application No. 8-171850 etc. is a method for dispensing a droplet
7
from a droplet dispensing device
6
having a single nozzle as shown in
FIGS. 14A
,
14
B, and
14
C. there is the limit of increase in throughput in the case where a plurality of droplets have to be dispensed to each element, however.
The present invention provides a method for producing an electron source by adopting a novel method for dispensing the material for formation of the electron emitting section.
SUMMARY OF THE INVENTION
An aspect of the invention is a method for producing an electron source as described below.
The production method of electron source is a method for producing an electron source having a plurality of electron emitting portions, said method comprising a step of:
by use of a plurality of output portions for respectively outputting a substantially homogeneous material for formation of said electron emitting portions, performing at least one dispensing operation of said material from each of the output portions to each of plural objective portions to which the material for formation of said electron emitting portions is to be dispensed.
This method suppresses the variation in the material dispensed to the respective objective portions even with the structure using the plural output portions and, particularly, it suppresses the variation in amounts of the material dispensed.
In the above method of the invention, it is preferred that each of said objective portions be subjected to an identical combination of dispensing operations of the material from said plural output portions. Here, the identical combination is that each objective portion undergoes the same number of dispensing operations of the material by the plurality of output portions and thus the numbers of dispensing operations from each output portion are identical among the objective portions. For example, in the case of two output portions being used, dispensing of the material from one output portion is carried out p (≧1) times for each objective portion, dispensing of the material from the other output portion is carried out q (≧1) times for each objective
Hasegawa Mitsutoshi
Mishima Seiji
Sando Kazuhiro
Shigeoka Kazuya
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Patel Nimeshkumar D.
Williams Joseph
LandOfFree
Method and apparatus for producing electron source using... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for producing electron source using..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for producing electron source using... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2502871