Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
2000-05-26
2002-10-29
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S492000, C313S497000, C315S169100
Reexamination Certificate
active
06472815
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a fluorescent luminous device including cathodes and a plurality of anode dots, and more particularly to a fluorescent luminous device effectively available as a printer head for optical writing, a graphic display device for displaying any desired characters or figures and the like. When the fluorescent luminous device of the present invention is used as a printer head, it may be commonly applied to various kinds of optical printers for writing on a photosensitive drum, writing on a photosensitive film and the like.
Now, a conventional fluorescent printer head will be described with reference to
FIG. 11. A
conventional fluorescent printer head generally designated at reference numeral
100
includes an anode substrate
102
constituting a part of an envelope, which anode substrate is provided thereon with two anode chains
107
and
108
each constituted of a plurality of anode dots
106
. The anode dots
106
of the anode chain
107
and those of the anode chain
108
are arranged in an offset manner with respect to each other. The respective two anode dots
106
of the anode chains
107
and
108
obliquely opposite to each other and adjacent to each other are connected together and led out to one side of the anode chains
107
and
108
, resulting in being connected to an IC acting as an anode drive means. The fluorescent printer head
100
also includes a first cathode
112
and a second cathode
113
stretchedly arranged above the anode chains
107
and
108
, respectively. Further, the fluorescent printer head
100
includes a shield electrode
120
arranged between the anodes chains
107
and
108
, as well as a first control electrode
130
and a second control electrode
131
respectively arranged outside the first and second cathodes
112
and
113
, with the cathodes
112
and
113
and shield electrode
120
being interposed between the first control electrode
130
and the second control electrode
131
. The shield electrode
120
has a positive voltage constantly applied thereto. The respective two anode dots
106
of the anode chains
107
and
108
obliquely opposite to each other are driven in order by the IC. In synchronism with the driving, the control electrode
130
or
131
has a selection signal fed thereto. When this results in the first control electrode
130
being selected, electrons are permitted to enter between the first control electrode
130
and the shield electrode
120
, to thereby impinge on the anode dots
106
of the anode chain
107
to which a drive signal is fed. In this instance, the second control electrode
131
has a negative voltage applied thereto to form an electric field, which prevents electrons emitted from the second cathode
113
from impinging on the anode dots
106
.
Thus, in the conventional fluorescent printer head
100
thus constructed, it is required that the first and second control electrodes
130
and
131
which are constructed so as to be controlled independently from each other are arranged for the respective anode chains
107
and
108
in order to select the anode chains. Also, the conventional fluorescent printer head
100
requires a power supply for applying a negative potential to each of the first and second control electrode
130
and
131
.
Also, in order to increase an anode potential to enhance luminance in the conventional fluorescent printer head
100
, it is required to increase a negative potential of the non-selected control electrode to prevent leakage luminescence of the non-selected selected anode chain. Further, this requires to increase a capacity of the power supply for negative potential application.
In addition, an increase in negative potential of the non-selected control electrode by increasing an anode potential causes a potential difference between the anode an the control electrode to be highly increased. However, in the fluorescent printer head
100
, the control electrodes
130
and
131
and anode wirings are arranged in proximity to each other in a vertical direction so as to be spaced from each other at a distance as small as 10 to 20 &mgr;m, so that an increase in potential difference therebetween causes dielectric breakdown to readily occur in the envelope.
SUMMARY OF THE INVENTION
The present invention has been made in view of the foregoing disadvantage of the prior art.
Accordingly, it is an object of the present invention to provide a fluorescent luminous device which is capable of eliminating arrangement of independently controllable control electrodes and a power supply for applying a negative potential to the control electrodes.
It is another object of the present invention to provide a fluorescent luminous device which is capable of being small-sized and reduced in manufacturing cost.
It is a further object of the present invention to provide a fluorescent luminous device which is capable of minimizing dielectric breakdown between electrodes.
In accordance with the present invention, a fluorescent luminous device is provided. The fluorescent luminous an anode substrate and an anode including a plurality of anode chains each constituted of a plurality of anode dots arranged so as to be spaced from each other at predetermined intervals on the anode substrate. The anode dots of the anode chains which correspond to each other are connected together. The fluorescent luminous device also includes an anode drive means for driving the anode dots of the anode, cathodes arranged above the anode chains, respectively, and a cathode selection means for applying a voltage to the cathodes independently from each other to select the anode chains.
In a preferred embodiment of the present invention, the cathode selection means applies a positive potential to the cathodes non-selected and a zero or negative potential to the cathodes selected.
In a preferred embodiment of the present invention, the fluorescent luminous device further includes a shield electrode arranged between each two of the cathodes so as to separate spaces above the anode chains from each other. The shield electrode has a zero or positive potential applied thereto.
In a preferred embodiment of the present invention, the fluorescent luminous device further includes a cut-off electrode having a potential lower than a positive potential which is applied to the cathodes applied thereto.
In a preferred embodiment of the present invention, the positive potential applied to the cathodes is lower than a positive potential applied to the anode.
In a preferred embodiment of the present invention, the fluorescent luminous device further includes a shield electrode arranged between each two of the cathodes so as to separate spaces above the anode chains from each other and a cut-off electrode for preventing electrons from being discharged from the non-selected cathodes to the anode chains corresponding thereto. The shield electrode and cut-off electrode are integrally constructed so as to cover the cathodes and have a potential lower than a positive potential which is applied to the cathodes applied thereto.
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Kobori Yoichi
Saito Masao
Shimizu Yukihiko
Ueda Kinya
Yamaguchi Hiroshi
Futaba Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Patel Vip
Quarterman Kevin
LandOfFree
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