Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With reflector – opaque mask – or optical element integral...
Reexamination Certificate
2002-06-05
2003-09-09
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With reflector, opaque mask, or optical element integral...
C257S099000, C257S100000, C313S493000, C313S496000, C313S340000, C313S349000, C313S278000, C313S257000
Reexamination Certificate
active
06617616
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a chip-in-glass fluorescent display device having a semiconductor device disposed inside an envelope thereof; and, more particularly, to a semiconductor device built-in fluorescent display device having a semiconductor device arranged in a space under a supporting member of filament-shaped cathodes.
BACKGROUND OF THE INVENTION
Generally, a chip-in-glass fluorescent display device includes a semiconductor device such as an integrated circuit (IC) usually incorporating therein a drive circuit and a control circuit, wherein the semiconductor device is installed inside a highly vacuumed envelope of the display device. Such a chip-in-glass fluorescent display device is advantageous in that a module employing the display device can be small-sized and the circuit thereof rarely needs wirings for an external connection.
However, the semiconductor device installed inside the envelope of the above-mentioned fluorescent display device forms a dead space on a display area (i.e., an area for anodes), thereby reducing the display area. In addition, ultraviolet and visible rays incident from an exterior may cause an erroneous operation of the semiconductor device.
To prevent such problems, a prior art provides a chip-in-glass fluorescent display device shown in
FIGS. 1A and 1B
. To install a plurality of filament-shaped cathodes
50
(simply referred to as filaments hereinafter) at a certain pitch, an anchor
51
for supporting filaments
50
is fixedly provided on a supporting structure
52
. Since a semiconductor device
53
is disposed in a space under the supporting structure
52
, the loss of display area due to the installation of the semiconductor device
53
can be avoided and the semiconductor device
53
can be protected from the influence of an external light.
The configuration of the above-explained fluorescent display device is described in more detail. The supporting structure
52
of a metal plate has a top plate portion
52
a
, side plate portions
52
b
, and base plate portions
52
c
. The top plate portion
52
a
is disposed over the semiconductor device
53
. Each of the side plate portions
52
b
is bent down from a side edge of the top plate portion
52
a
(in a pitch direction of the filaments
50
) and serves to produce an installation space of the semiconductor device
53
under the top plate portion
52
a
. Each of the base plate portions
52
c
is bent from a lower portion of a corresponding side plate portion
52
b
and fixed to an anode plate
54
.
The anchor
51
has an anchor base portion
51
a
and a plurality of arms
51
b
extended therefrom. The anchor base portion
51
a
is fixed to an upper surface of the top plate portion
52
a
of the supporting structure
52
, wherein each of the arms
51
b
has a free end portion for fixing an end portion of a filament
50
. The free end portion of each arm
51
b
is upwardly extended with respect to the anchor base portion
51
. The filaments
50
with tension therein are stretched above the supporting structure
52
and the anchor base portion
51
a
with tension applied to each.
However, the prior art fluorescent display device described above suffers from certain drawbacks. That is, since the filaments
50
are disposed above the supporting structure
52
(and the anchor base portion
51
a
) covering the semiconductor device
53
, a gap is present at a relatively great height “FH” between the filament
50
and the anode plate
54
, thereby deteriorating the brightness of the fluorescent display device.
More specifically, in addition to the thickness of the semiconductor device
53
disposed on the anode plate
54
, a space is required between the semiconductor device
53
and the supporting structure
52
and, further, the filaments
50
are also vertically spaced apart from the anchor base portion
51
a
disposed on the supporting structure
52
. Therefore, the height “FH” measured from the anode plate
54
to the filament
50
is determined by the above-mentioned thickness and interposed space, wherein a minimum value thereof is usually about 1.3 mm. The relatively great height “FH” of the filaments
50
causes insufficient brightness when the fluorescent display device is used in a car in which a low voltage level, e.g., about 12 V, is applied thereto.
Actually, the height “FH” of the filament
50
needs to be about 0.9 to about 1.10 mm in case such a chip-in-glass fluorescent display device is employed in a car to be operated at a low voltage level. Moreover, some cases may need the height “FH” to be about 1.2 mm even under high voltage driving conditions and, for certain cases, such a conventional fluorescent display device cannot be used at all.
In view of fabricating the supporting structure
52
of the fluorescent display device shown in
FIGS. 1A and 1B
, it is difficult to bend the side plate portions
52
b
at a perpendicular angle of 90 degrees with respect to the top plate portion
52
a
or the base plate portions
52
c
. Consequently, after the supporting structure
52
is fixed on the anode plate
54
, each of the side plate portions
52
b
is slanted as shown in
FIG. 1B
, thereby shortening the length of the top plate portion
52
a
along the pitch direction of the filaments
50
. This results in reducing an effective area in the top plate portion
52
a
for mounting the anchor base portion
51
a
. As a result, the number of the filaments
50
, i.e., a width “FW” of the arranged filaments
50
, is limited and, therefore, a display area cannot be enlarged in the pitch direction of the filaments
50
.
On the other hand, the anchor
51
serves to apply a tension to the free end portion of each arm
51
b
in the pitch direction of the filaments
50
. Since, however, the area of the top plate portion
52
a
is small and the number of the arranged filaments
50
is limited, a dead space is formed at an end side along the pitch direction of the filaments
50
(at a right region in FIG.
1
B). Therefore, the display area of the conventional fluorescent display device is also decreased in the pitch direction of the filaments
50
.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a chip-in-glass fluorescent display device implementing a high brightness and a wide display area in spite of a low voltage driving condition.
In accordance with a preferred embodiment of the present invention, there is provided a fluorescent display device including an anode plate and a semiconductor device arranged thereon, wherein the anode plate forms a portion of an envelope of the display device and has an anode on an inner surface thereof, the display device further including: a supporting structure disposed on the anode plate, the supporting structure having a top plate portion overlapping the semiconductor device; and a tensioning member, disposed on the top plate portion of the supporting structure, for arranging a plurality of filament-shaped cathodes at a pitch between the semiconductor device and the top plate portion.
REFERENCES:
patent: 4142126 (1979-02-01), DuBois
patent: 4149105 (1979-04-01), Hirooka et al.
patent: 5834892 (1998-11-01), Kikuchi et al.
patent: 58194229 (1983-11-01), None
patent: 05205673 (1993-08-01), None
Bacon & Thomas PLLC
Flynn Nathan J.
Forde Remmon R.
Futaba Corporation
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