Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
2001-10-02
2003-06-24
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C315S169400, C313S505000
Reexamination Certificate
active
06583582
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of driving an electron source having a plurality of electron-emitting devices, an image-forming apparatus using the electron source, a method of driving the apparatus, and a method of manufacturing an electron source and image-forming apparatus.
2. Related Background Art
Conventionally, two types of devices, namely thermionic and cold cathode devices, are known as electron-emitting devices. Known examples of the cold cathode devices are field emission type electron-emitting devices (to be referred to as FE type electron-emitting devices hereinafter), metal/insulator/metal type electron-emitting devices (to be referred to as MIM type electron-emitting devices hereinafter), surface conduction electron-emitting devices.
Known examples of the FE type electron-emitting devices are described in W. P. Dyke and W. W. Dolan, “Field Emission”, Advance in Electron Physics, 8, 89 (1956) and C. A. Spindt, “Physical properties of thin-film field emission cathodes with molybdenum cones”, J. Appl. Phys., 47, 5248 (1976).
A known example of the MIM type electron-emitting devices is described in C. A. Mead, “Operation of Tunnel-Emission Devices”, J. Appl. Phys., 32, 646 (1961).
In addition, the following devices have been recently studied: Toshiaki Kusunoki, “Fluctuation-free Electron Emission from Non-formed Metal-Insulator-Metal (MIM) Cathodes Fabricated by Low Current Anodicoxidation”, Jpn. J. Appl. Phys. vol. 32 (1993), pp. L1695, Mutsumi Suzuki et al., “An MIM-Cathode Array for Cathode Luminescent Displays”, IDW '96, (1996), pp. 529, and the like.
A known example of surface-conduction electron-emitting devices is described in, e.g., M. I. Elinson, “Radio Eng. Electron Phys., 10 (1965) and other examples will be described later. The surface conduction electron-emitting device utilizes the phenomenon in which electrons are emitted by a small-area thin film formed on a substrate by flowing a current in parallel with the film surface. The surface conduction electron-emitting device includes electron-emitting devices using an SnO
2
thin film according to Elinson mentioned above, an Au thin film (G. Dittmer, “Thin Solid Films”, 9,317 (1972)), an In
2
O
2
/SnO
2
thin film (M. Hartwell and C. G. Fonstad, IEEE Trans. ED Conf., 519 (1975)), and the like.
Various arrangements of a plurality of electron-emitting devices constituting an electron source are adopted. For example, a matrix arrangement is available, in which a plurality of electron-emitting devices are arranged in the X and Y directions in the form of a matrix, and one electrode of each of the electron-emitting devices arranged on the same row is commonly connected to an X-direction wiring, while the other electrode of each of the electron-emitting devices arranged on the same column is commonly connected to a Y-direction wiring. A matrix arrangement will be described below with reference to FIG.
12
.
M X-direction wirings
62
include wirings Dx
1
, Dx
2
, . . . , Dxm and can be made of an electroconductive metal or the like formed by vacuum evaporation, printing, sputtering, or the like. A wiring material, thickness, and width are properly designed. Y-direction wirings
63
include n wirings Dy
1
, Dy
2
, . . . , Dyn and are formed in the same manner as the X-direction wirings
62
. A dielectric interlayer (not shown) is formed between the m X-direction wirings
62
and the n Y-direction wirings
63
to electrically isolate them (both m and n are positive integers).
The dielectric interlayer (not shown) is made of SiO
2
or the like formed by vacuum evaporation, printing, sputtering, or the like. The dielectric interlayer is formed in a desired shape on the entire surface or part of the surface of a base member
61
on which the X-direction wirings
62
are formed, and a thickness, material, and manufacturing method are properly set for the interlayer to withstand the potential difference at the intersections of the X-direction wirings
62
and the Y-direction wirings
63
, in particular. The X-direction wirings
62
and Y-direction wirings
63
extend as external terminals.
The m X-direction wirings
62
may also serve as the cathode electrodes of the electron-emitting devices. The n Y-direction wirings
63
may also serve as the gate electrodes of the electron-emitting devices. The dielectric interlayer may also serve as a dielectric layer of each electron-emitting device.
A scan signal application means for applying a scan signal for selecting a row of electron-emitting devices
64
arranged in the X direction is connected to the X-direction wirings
62
. A modulated signal generating means for modulating data from each column of electron-emitting devices
64
arranged in the Y direction in accordance with an input signal is connected to the Y-direction wirings
63
. A driving voltage applied to each electron-emitting device is a difference voltage between a scan signal applied to the device and a modulated signal supplied from a signal line.
SUMMARY OF THE INVENTION
In order to apply an electron-emitting device to an image-forming apparatus, an emission current for making a phosphor emit light with sufficient luminance is required. On the other hand, in setting the electron-emitting device in the OFF state, the electron-emitting device must be controlled without causing it to emit electrons. Obviously, to increase the number of grayscale levels is an important factor in improving image quality. In addition, to realize a high-resolution display, an electron beam applied to a phosphor needs to have a small diameter, and many pixels are required. It is also important that such devices can be easily manufactured.
An example of the conventional FE type electron-emitting device is a Spindt type electron-emitting device. The Spindt type electron-emitting device uses a microchip as an electron-emitting member, and electrons are emitted from the tip of the microchip. As the emission current density is increased to make a phosphor emit light, thermal damage to the electron-emitting portion is induced, thus limiting the life of the FE device. In addition, electrons emitted from the tip tend to diverge due to the electric field formed by the gate electrode. This makes it impossible to reduce the beam diameter.
To overcome such drawbacks of the EF device, various solutions have been proposed.
As an example of a technique of preventing divergence of an electron beam, a technique of placing a focusing electrode above the electron-emitting portion is available. According to this technique, an emitted electron beam is generally focused by the negative potential of the focusing electrode. This complicates the manufacturing process and leads to an increase in manufacturing cost.
As another example of the technique of reducing the diameter of an electron beam, a method without the formation of a microchip like the one formed in Spindt type electron-emitting device is available. For example, such methods are disclosed in Japanese Laid-Open Patent Application Nos. 8-096703 and 8-096704, U.S. Pat. No. 5,939,823, U.S. Pat. No. 5,989,404, and the like.
According to this device, since electron emission is performed from a thin film formed in a hole, a flat equipotential surface is formed on the electron-emitting surface, thereby reducing the divergence of an electron beam.
By using a material with a low work function as an electron-emitting substance, electron emission can be performed without forming any microchip. This makes it possible to realize a low driving voltage. In addition, a manufacturing method is relatively simple. Furthermore, since electron emission is performed on a surface, an electric field does not concentrate, and no chip destruction occurs. The life of this device is therefore long.
According to such FE type electron-emitting devices, an electric field (in general, 1×10
8
V/m to 1×10
10
V/m in the case of the Spindt type) required to emit electrons from a gate electrode near an electron-emitting substance connected to a
Canon Kabushiki Kaisha
Dinh Trinh Vo
Fitzpatrick ,Cella, Harper & Scinto
Wong Don
LandOfFree
Method of driving electron source and image-forming... 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 of driving electron source and image-forming..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of driving electron source and image-forming... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3087437