Image forming apparatus

Details Image forming apparatus Image forming apparatus

2000-07-28

2003-04-01

Patel, Ashok (Department: 2879)

Electric lamp and discharge devices

With luminescent solid or liquid material

Vacuum-type tube

C313S497000, C313S309000, C313S336000, C313S351000, C313S306000

Reexamination Certificate

active

06541905

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to an image forming apparatus utilizing electron-emitting devices and, more particularly to an image forming apparatus in which a spacer as a support member is provided within the apparatus.
2. Description of Related Art
Conventionally, two types of electron-beam emitting devices, namely thermionic cathode electron-beam emitting devices and cold cathode electron-beam devices are known. Examples of cold cathode electron-emitting devices are electron-emitting devices of surface-conduction emission (hereinafter abbreviated to “SCE”) type, field emission (hereinafter abbreviated to “FE”) type, and metal/insulator/metal (hereinafter abbreviated to “MIM”) type.
A known example of the SCE type electron-emitting devices is described in “Radio Eng. Electron Phys., 10, 1290” (1965) by M. I. Elinson, and other examples will be described later.
The SCE type electron-emitting device utilizes a phenomenon where electron-emission is produced in a small-area thin film formed on a substrate, by passing a current parallel to the film surface. As the SCE type electron-emitting devices, electron-emitting devices using an SnO
2
thin film by Elinson mentioned above, an Au thin film by G. Dittmer (“Thin solid Films”, 9,317 (1972)), an In
2
O
3
/SnO
2
thin film by M. Hartwell and C. G. Fonstad (“IEEE Trans. ED Conf.”, 519 (1975)), a carbon thin film by Hisashi Araki et al. (“Vacuum”, vol. 26, No. 1, p. 22 (1983)) are reported.
FIG. 5
is a plan view of the SCE type electron-emitting device by M. Hartwell and C. G. Fonstad described above, as a typical example of the structure of the SCE type electron-emitting devices. In
FIG. 5
, reference numeral
501
denotes a substrate;
502
, a conductive thin film of a metal oxide formed by sputtering, having a H-shaped pattern. An electron-emitting portion
503
is formed by electrification process referred to as “energization forming” to be described later, on the conductive thin film
502
. In
FIG. 5
, the interval L is set to 0.1-1 mm, and the width W is set to 0.1 mm. Note that the electron-emitting portion
503
is shown at approximately the center of the conductive thin film
502
, with a rectangular shape, for convenience of illustration, however, this does not exactly show the position and shape of the actual electron-emitting portion
503
.
In these conventional SCE type electron-emitting devices by M. Hartwell and the others, the electron emission portion
503
is typically formed by performing electrification, “energization-forming”, on the conductive thin film
502
. According to the energization forming process, electrification is made by applying a direct current where voltage increases at a very slow rate of, e.g., 1 V/min., to both ends of the conductive thin film
502
, so as to partially destroy or deform the conductive thin film
502
, thus form the electron-emitting portion
503
with electrically high resistance. Note that the destroyed or deformed part of the conductive thin film
502
have a fissure. Upon application of appropriate voltage to the conductive thin film
502
after the energization forming, electron emission is made near the fissures.
Examples of the FE type electron-emitting devices are given in, e.g., W. P. Dyke & 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 Molybdenium Cones”, J. Appl. Phys., 47,5248 (1976).
FIG. 6
is a cross-sectional view of the FE type electron-emitting device according to C. A. spindt and the others mentioned above, as a typical example of the structure of the FE type electron-emitting devices. In
FIG. 6
, numeral
601
denotes a substrate;
602
, an emitter wiring electrode;
605
, an emitter corn;
603
, an insulating layer; and
604
, a gate electrode. In this device, electron emission is made by applying an appropriate voltage between the emitter corn
605
and the gate electrode
604
.
Further, as-another example of the FE type electron-emitting devices, a structure where the emitter and the gate electrode are provided approximately parallel to the substrate surface is known.
Further, examples of the MIM type electron-emitting devices are described in, e.g., C. A. Mead, “Operation of Tunnel-Emission Devices”, J. Apply. Phys., 32, 646 (1961), and other references.
FIG. 7
is a cross-sectional view showing a typical structure of the MIM type electron-emitting device. In
FIG. 7
, numeral
701
denotes a substrate;
702
, a lower electrode comprising a metal member;
703
, a thin insulating layer having a thickness of about 100 Å; and
704
, an upper electrode comprising a metal member having a thickness of 80 to 300 Å. In the MIM type electron-emitting device, electron emission is caused from the surface of the upper electrode
704
by applying an appropriate voltage between the upper and lower electrodes
703
and
702
.
In comparison with the thermionic cathode electron-beam emitting devices, the cold cathode electron-emitting devices can obtain electron emission at a lower temperature and, therefore do not need a heater. Accordingly, the cold cathode electron-emitting devices has a structure simpler than that of the thermionic cathode electron-emitting devices, which enables more compact electron-emitting devices. In addition, even if a multitude of electron-emitting devices are arranged on a substrate in high density, heat-melting of the substrate does not easily occur. Further, different from the thermionic cathode electron-emitting devices that have slow response because they operate after being heated, the cold cathode electron-emitting devices have quick response.
For these reasons, the applications of the cold cathode electron-emitting devices have been positively studied.
For example, the SCE type electron-emitting devices have the simplest structure and therefore can be easily manufactured, they are advantageous for forming a large number of electron-emitting devices on a large area. As disclosed in Japanese Patent Application Laid-Open No. 64-31332, many methods for arranging the SCE type electron-emitting devices and driving them have been studied.
Also, applications of the SCE type electron-emitting devices to, e.g., image forming apparatuses such as an image display device and an image recording device, electrical charge beam source and the like have been proposed.
Especially, as applications to image display apparatuses, as shown in the U.S. Pat. No. 5,066,833 by the present applicant, Japanese Patent Applications Laid-Open Nos. 2-257551 and 4-28137, an image display apparatus using the combination of SCE type electron-emitting devices and a fluorescent material which emits light upon reception of an electronic beam has been studied. This type of image display apparatus is expected to have excellent characteristics better than other conventional image display apparatuses. For example, in comparison with recently focused liquid crystal display apparatuses, the above display apparatus is superior in that it does not require a backlight since it is a self light-emitting type and that it has a wide view angle.
Methods for arranging a large number of FE type electron-emitting devices and driving the devices are disclosed in, e.g., the U.S. Pat. No. 4,904,895 by the present applicant. As an application of the FE type electron-emitting devices to an image display apparatus, a flat-type display device is reported by R. Meyer and others (“Recent Development on Microtips Display at LETI”, Tech. Digest of 4th Int. Vacuum Microelectronics Conf., Nagahama, pp. 6-9 (1991)).
An application of the MIM type electron-emitting devices as an image display device, where a large number of MIM type electron-emitting devices are arranged, is disclosed in Japanese Patent Application Laid-Open No. 3-55738 by the present applicant.
Accordingly, a multi electron-beam source having cold cathode electron-emitting devices wired in a simple matrix has possibilities in a variety of applications. For example, an elect

Affiliated with

Also associated with

Rating

Image forming apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Image forming apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming apparatus will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3094863