Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-04-26
2003-06-03
Arbes, Carl J. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S029000, C029S593000
Reexamination Certificate
active
06571464
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to spacer structures which are located between a faceplate structure and a backplate structure in a flat panel display. The present invention also relates to methods for fabricating and installing such spacer structures.
BACKGROUND OF THE INVENTION
Flat cathode ray tube (CRT) displays include displays which exhibit a large aspect ratio (e.g., 10:1 or greater) with respect to conventional deflected-beam CRT displays, and which display an image in response to electrons striking a light emissive material. The aspect ratio is defined as the diagonal length of the display surface to the display thickness. The electrons which strike the light emissive material can be generated by various devices, such as by field emitter cathodes or thermionic cathodes. As used herein, flat CRT displays are referred to as flat panel displays.
Conventional flat panel displays typically include a faceplate structure and a backplate structure which are joined by connecting walls around the periphery of the faceplate and backplate structures. The resulting enclosure is usually held at a vacuum pressure. To prevent collapse of the flat panel display under the atmospheric pressure, a plurality of spacers are typically located between the faceplate and backplate structures at a centrally located active region of the flat panel display.
The faceplate structure includes an insulating faceplate (typically glass) and a light-emitting structure formed on an interior surface of the insulating faceplate. The light emitting structure includes light emissive materials, or phosphors, which define the active region of the display. The backplate structure includes an insulating backplate and an electron emitting structure located on an interior surface of the backplate. The electron emitting structure includes a plurality of electron-emitting elements (e.g., field emitters) which are selectively excited to release electrons. The light emitting structure is held at a relatively high positive voltage (e.g., 200 V to 10 kV) with respect to the electron emitting structure. As a result, the electrons released by the electron-emitting elements are accelerated toward the phosphor of the light emitting structure, causing the phosphor to emit light which is seen by a viewer at the exterior surface of the faceplate (the “viewing surface”).
FIG. 1
is a schematic representation of the viewing surface of a flat panel display
50
. The faceplate structure of flat panel display
50
includes a light emitting structure which is arranged in a plurality of rows of light emitting elements (i.e., pixel rows), such as pixel rows
1
-
31
. Flat panel display
50
typically includes hundreds of pixel rows, with each row typically including hundreds of pixels.
The electron emitting structure of flat panel display
50
is arranged in rows of electron emitting elements which correspond with the pixel rows
1
-
31
of the faceplate structure. Each row of electron emitting elements includes electron emitting elements which correspond to each of the pixels on the light emitting structure. The electron emitting elements are activated, thereby causing electrons to be transmitted to the corresponding pixels to create an image at the viewing surface of the flat panel display
50
.
Spacer walls
41
-
43
are located between the faceplate structure and the backplate structure. Pixel rows
1
-
31
and spacers walls
41
-
43
are greatly enlarged in
FIG. 1
for purposes of illustration. It is desirable for spacers
41
-
43
to extend horizontally across display
50
in parallel with pixel rows
1
-
31
. Spacer wall
41
is illustrated as a properly positioned spacer wall. Spacer wall
41
is perfectly located between pixel rows
8
and
9
, such that the spacer wall
41
does not obstruct any of the pixels in pixel rows
8
and
9
. While spacer wall
41
illustrates the ideal positioning of a spacer wall, spacer walls
42
and
43
illustrate the positioning which results from conventional methods. Spacer wall
42
, although straight, is not located perfectly in parallel with pixel rows
16
and
17
. As a result, spacer wall
42
obstructs pixels near the ends of pixel rows
16
and
17
. The obstructed pixels will not receive the intended electrons from the electron emitting structure, thereby resulting in degradation of the image viewed by the user. Spacer wall
43
exhibits a waviness which may be inherent in the material used to make the spacer wall
43
. Spacer wall
43
therefore obstructs pixels throughout pixel rows
24
and
25
, again degrading the image seen by the viewer. Spacer walls
41
-
43
can also be positioned in a non-perpendicular manner between the faceplate and backplate structures. Such a non-perpendicular positioning can result in the undesirable deflection of electrons. This electron deflection can also degrade the image seen by the viewer.
Consequently, it is desirable to have spacer walls which are precisely aligned within the flat panel display. However, the relatively small size of the spacer walls
41
-
43
makes it difficult to position these spacer walls
41
-
43
between the faceplate and backplate structures. Even if the spacer walls
41
-
43
are initially aligned properly, these spacer walls
41
-
43
can subsequently shift out of alignment during normal operation of the flat panel display. This shifting may occur as a result of heating or physical shock experienced by the flat panel display.
Spacer walls
41
-
43
can include face electrodes which are used to control the voltage distribution between the faceplate and backplate structures adjacent to the spacers
41
-
43
. Predetermined external voltages are applied to the face electrodes to control this voltage distribution. It is often difficult to make an electrical connection between these face electrodes and either the faceplate structure and the backplate structure, such that the external voltages can be applied to the face electrodes.
It would therefore be desirable to have a spacer structure which is easy to locate between a faceplate structure and a backplate structure. It would also be desirable if this spacer would remain in precise alignment after assembly of the flat panel display, even in view of exposure to thermal cycling and physical shock. It would further be desirable if such a spacer facilitated easy connection of face electrodes to the faceplate and/or backplate structures.
SUMMARY
Accordingly, the present invention provides a spacer structure which can be located between a faceplate structure and a backplate structure of a flat panel display. In one embodiment, the spacer structure includes a spacer wall having a first edge surface for contacting the faceplate structure and a second edge surface, opposite the first edge surface, for contacting the backplate structure. A first face surface extends between the first and second edge surfaces. A second face surface, which is located opposite the first face surface, extends between the first and second edge surfaces. The spacer wall further has a first end, and a second end located distal from the first end.
A first spacer foot is located on the first face surface at the first end of said spacer wall. The first spacer foot has a support surface which is co-planar with the first edge surface of the spacer wall. Similarly, a second spacer foot is located on the first face surface at the second end of said spacer wall. The second spacer foot has a support surface which is also co-planar with the first edge surface of the spacer wall. The first and second spacer feet advantageously enable the spacer wall to be supported in a free-standing position when the spacer wall is set on the first edge surface. To enhance the stability of the free-standing configuration of the spacer-wall, the support surfaces of the first and second spacer feet are located perpendicular to the first and second face surfaces of the spacer wall. When the spacer wall is positioned between a faceplate structure and a backplate structure, the support surfaces contact the facepla
Chakarov Vasil M.
Cho Steve T.
Conte Alfred S.
Duboc, Jr. Robert M.
Fahlen Theodore S.
Arbes Carl J.
Candescent Technologies Corporation
Meetin Ronald J.
Skjerven Morrill LLP
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