Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
2003-09-05
2004-12-07
Vu, David (Department: 2828)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S306000, C313S336000
Reexamination Certificate
active
06828722
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electron beam apparatus including a first substrate having an region from which electrons are emitted, a second substrate having an region which is irradiated by the emitted electrons, and a spacer arranged between the first and the second substrates for forming an atmospheric pressure resistant structure, and to an image display apparatus using the electron beam apparatus.
2. Related Background Art
Two kinds of electron-emitting devices which are a hot-cathode device and a cold-cathode device are conventionally known. As the cold-cathode device, for example, a surface conduction type electron-emitting device, a field emission type (FE type) electron-emitting device, a metal/insulating layer/metal type (MIM type) electron-emitting device and the like are known.
The surface conduction type electron-emitting device utilizes the phenomenon in which electrons are emitted by the current flowing parallel to the surface of the thin film which is formed on the substrate and has a small area. As the surface conduction type electron-emitting device, for example, the following devices are known: the device using a SnO
2
thin film which is disclosed in M. I. Elinson, “Radio Eng. Electron Phys”, 10, 1290, (1965), the device using an Au thin film which is disclosed in G. Dittmer, “Thin Solid Films”, 9, 317 (1972), the device using In
2
O
3
/SnO
2
thin film which is disclosed in M. Hartwell and C. G. Fonstad, “IEEE Trans. ED Conf.”, 519 (1975), the device using a carbon thin film which is disclosed in H. Araki, “Vacuum”, vol. 26, No. 1, 22 (1983), and the like.
Because especially the surface conduction type electron-emitting device has a simple structure and is easily produced among the cold-cathode type electron-emitting devices, the surface conduction type electron-emitting device has an advantage that many devices can be formed over a large area. Moreover, as the application of the surface conduction type electron-emitting device, for example, the application to an image display apparatus, an image formation apparatus such as an image recording apparatus and the like, a charged beam source, and the like has been researched. In particular, as the application to the image display apparatus, for example, the present applicant proposed an image display apparatus using surface conduction type electron-emitting devices in combination with phosphors which emitted light by being irradiated by electron beams as it was disclosed in U.S. Patent No. 5,066,883. The image display apparatus using the surface conduction type electron-emitting devices in combination with the phosphors is expected to have superior characteristics in comparison with other conventional type image display apparatus. For example, even if the image display apparatus is compared with a liquid crystal display apparatus which has come into wide use recently, the image display apparatus has advantage in that the image display apparatus does not need any backlight because the apparatus is self light emission type, and in that the image display apparatus has a wide view angle.
On the other hand, a method for driving many arranged FE type electron-emitting device is disclosed in U.S. Pat. No. 4,904,895 by the present applicant. Moreover, as an example of the application of the FE type electron-emitting device to an image display apparatus, for example, a flat-panel type display apparatus reported by R. Meyer (R. Meyer “Recent Development Micro-tips Display at LETI”, Tech. Digest of 4
th
Int. Vacuum Micro Electronics Conf. Nagahama, pp. 6-9 (1991)) is known.
Moreover, in recent years, it has been examined to use a carbon nanotube as an electron-emitting device.
Among the image formation apparatus using the electron-emitting devices as described above, because the flat panel type display apparatus having a thin depth can save a space and is light in weight, the flat panel type display is attracting public attention as one to replace a cathode-ray tube type display apparatus.
FIG. 11
is a perspective view showing an example of the flat panel type image display apparatus. The panel of the display apparatus is shown in a partially cutaway state for showing the internal structure of the apparatus. As shown in
FIG. 11
, a plurality of cold-cathode devices (hereupon, surface conduction type electron-emitting devices are shown as an example)
3112
, which are electron sources, is formed in a matrix on a substrate
3111
. The substrate
3111
is piled on a rear plate
3115
. The rear plate
3115
, a side wall
3116
forming a frame, and a face plate
3117
, on which a fluorescent film
3118
and an anode electrode (a metal back)
3119
are formed, constitute an envelope (a hermetic container) for keeping the inside of the display panel vacuum. Incidentally, the cold-cathode devices
3112
are connected to wiring
3113
and
3114
arranged in a matrix.
The inside of the hermetic container is kept to be vacuum at about 1.33×10
−4
Pa (10
−6
Torr). The larger the display area of the image display apparatus becomes, the more the means for preventing the deformation or the destruction of the rear plate
3115
and the faceplate
3117
caused by atmospheric pressure difference between the inside of the hermetic container and the outside thereof becomes necessary. The method for preventing the deformation or the destruction by thickening the rear plate
3115
and the face plate
3117
causes the distortion of images and parallax when the image display apparatus is looked at obliquely in addition to the increase of the weight of the image display apparatus. Accordingly, as shown in
FIG. 11
, spacers (called as ribs in some cases)
312
, which are made of relatively thin glass plates and are structural supporting members for withstanding the atmospheric pressure, are provided. By the spacers
3120
, the interval between the rear plate
3115
and the face pate
3117
, more correctly the interval between the substrate
3111
, on which a multi-beam electron source is formed, and the metal back
3119
, is normally kept to be several millimeters or less, and the inside of the hermetic container is kept to be highly vacuum, as described above.
The necessary number of the spacers
3120
judged from the structural viewpoint is effectively arranged. When the spacers
3120
are formed to have a length shorter than the image display region (the region in which the metal back
3119
is formed and the orthogonal projection region of the metal back
3119
to the rear plate
3115
), the number of the spacers
3120
and the setting man-hour of the spacers
3120
are obliged to increase. Accordingly, it is preferable to provide the spacers
3120
having a length equal to the image display region or longer.
The image display apparatus described above has the following problems.
Electron beams emitted from the electron-emitting devices of the substrate
3111
on the rear plate
3115
to the face plate
3117
impinge on the face plate
3117
. After the impingement, a part of the electrons are reflected as secondary electrons, and are emitted to the substrate
3111
and the spacers
3120
. When the substrate
3111
is charged excessively owing to the secondary electrons which impinged on the substrate
3111
, the substrate
3111
generate discharges, which give bad influence to images. Moreover, when the spacers
3120
is charged excessively owing to the secondary electrons which impinge on spacers
3120
, the charging gives influence to the orbits of the electron beams near to the spacers
3120
to change the irradiation positions on the face plate
3117
. Consequently, the uniformity of the images near to the spacers
3120
decreases to give bad influence to the image qualities.
It is known that the location of a potential regulation plate made of metal between the rear plate
3115
and the face plate
3117
in the state of being parallel to both the plates (the substrate) is effective. The potential regulation plate has thorough holes at the positions where
Niibori Kenji
Ueda Kazuyuki
LandOfFree
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