Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
1998-12-23
2001-07-10
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S496000, C313S310000
Reexamination Certificate
active
06259198
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an electron emission device, and more particularly to an electron emission device based flat panel display apparatus which has a plurality of electron emission devices arranged in an image display array, for example, in a matrix form.
2. Description of the Related Art
Conventionally, in field electron emission display apparatuses, a Field Emission Display (FED) is known as a planar emission display device equipped with an array of cold-cathode electron emission source which does not require cathode heating. The emission principle of, for example, an FED using Spindt-type cold cathodes of minute protrusions is as follows: Its emission principle is like a Cathode Ray Tube (CRT), although this FED has a cathode array of Spindt-type protrusions which is different from that of CRT. In the FED, electrons are drawn into a vacuum space by means of each gate electrode spaced apart from the Spindt-type cathode, and the electrons are made to impinge upon the fluorescent substance that is coated on a transparent anode, thereby causing light emission.
This FED, however, has a problem of low production yield because the manufacture of the minute Spindt-type emitter arrays as a cold cathode is complex and involves many processes.
There is also known an electron emission device with electron emission devices of metal-insulator-metal (MIM) structure as a planar electron emission source. The electron emission device with the MIM structure comprises an Al underlayer as a base electrode, an Al
2
O
3
insulator layer with about 10 nm thickness, and an Au overlayer, as a top electrode with about 10 nm thickness which are formed in order on the substrate. In the case that this MIM device is placed under an opposing electrode in a vacuum, when a voltage is applied between the Al underlayer and the Au overlayer and, at the same time, an acceleration voltage is applied to the opposing electrode, then some of electrons emit out of the Au overlayer and reach the opposing electrode.
However, even the electron emission device with the MIM structure merely achieves an emitting current of approximately 1×10
−5
A/cm
2
, and an emitting current ratio of approximately 1×10
−3
, and is still incapable of providing a sufficient amount of emitting electrons for displaying an image. Therefore, a flat panel display apparatus employing a plurality of such devices is also still premature for practical use.
OBJECT AND SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances, and thus an object thereof is to provide a flat panel display apparatus which employs electron emission devices having an electron emitting efficiency high enough to stably emit electrons at a low voltage applied thereto.
The present invention provides an electron emission device based flat panel display apparatus which comprises:
a pair of a back substrate and an optically transparent front substrate opposing to each other with a vacuum space interposed therebetween;
a plurality of electron emission devices, each including an electron-supply layer made of metal or semiconductor, formed on ohmic electrodes formed on a surface of the back substrate proximate to the vacuum space, an insulator layer formed on the electron-supply layer, and a thin-film metal electrode formed on the insulator layer and facing the vacuum space,
wherein the front substrate includes collector electrodes formed on its surface proximate to the vacuum space, fluorescent material layers formed on the collector electrodes, and an image display array composed of a plurality of light emitting elements corresponding to the fluorescent material layers;
insulative support members formed on the back substrate and disposed between adjacent ones of the electron emission devices; and
a plurality of electrodes, each disposed between adjacent ones of the thin-film metal electrodes and on the insulative support members for electrically connecting the thin-film metal electrodes.
According to the electron emission device based flat panel display apparatus having the structure mentioned above, the bus electrodes can be prevented from breaking due to a difference in level in the electron emission devices on the back substrate.
In the embodiment of the electron emission device based flat panel display apparatus, the distance from said back substrate to the surfaces of said insulative support members proximate to said vacuum space is substantially equal to the distance from said back substrate to the surface of said thin-film metal electrodes proximate to said vacuum space.
In the embodiment of the invention, the above electron emission device based flat panel display apparatus further comprises a plurality of bus electrodes, each of said bus electrodes arranged to electrically connect adjacent ones of said thin-film metal electrodes, said bus electrodes having a width between said thin-film metal electrodes larger than a width on said thin-film metal electrodes.
In another embodiment of the electron emission device based flat panel display apparatus, said back substrate includes a plurality of first insulative ribs, each of said first insulative ribs disposed between said electron emission devices, and having a height larger than the distance from said back substrate to the surface of said thin-film metal electrode proximate to said vacuum space, each of said first insulative ribs protruding into said vacuum space.
In another embodiment of the electron emission device based flat panel display apparatus, said rear ramparts are formed on said insulative support members.
In a further embodiment of the electron emission device based flat panel display apparatus, said front substrate includes a plurality of front ramparts, each of said front ramparts having a height larger than the distance from said front substrate to the surface of said fluorescent material layers proximate to said vacuum space, each of said front ramparts protruding into said vacuum space to abut to said rear ramparts.
In the embodiment of the electron emission device based flat panel display apparatus, said front ramparts extend in a direction in which said ohmic electrodes extend, and abut to said plurality of rear ramparts.
In another embodiment of the electron emission device based flat panel display apparatus, each of said rear ramparts includes an overhung portion on the top thereof protruding in a direction substantially parallel with said back substrate.
In a still further embodiment of the electron emission device based flat panel display apparatus, said ohmic electrodes and said electrodes are stripe-like electrodes, and arranged to intersect orthogonal to each other.
REFERENCES:
patent: 5652474 (1997-07-01), Wilshaw et al.
patent: 5894189 (1999-04-01), Ogasawara et al.
Chuman Takashi
Ito Hiroshi
Iwasaki Shingo
Negishi Nobuyasu
Ogasawara Kiyohide
Morgan & Lewis & Bockius, LLP
Patel Vip
Pioneer Electronic Corporation
Williams Joseph
LandOfFree
Flat panel display apparatus with an array of electron... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flat panel display apparatus with an array of electron..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flat panel display apparatus with an array of electron... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2567021