Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
2002-03-01
2004-04-06
Wong, Don (Department: 2821)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S272000, C445S046000
Reexamination Certificate
active
06717350
ABSTRACT:
FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
The present invention relates to an electron tube which includes cathode linear members (e.g. cathode filaments), linear members (e.g. wire grids), getter linear members, and support auxiliary members (e.g. linear spacers and linear dampers), and to a method of manufacturing the same.
DISCUSSION OF THE INVENTION
A fluorescent luminous tube, being one of conventional electron tubes, will be explained below by referring to
FIGS. 12 and 13
.
FIG.
12
(
a
) is a plan view illustrating a glass substrate on which cathode filaments, a linear spacer, a linear damper, and others are mounted. FIG.
12
(
b
) is a cross-sectional view of the portion taken along the line X
1
-X
2
in FIG.
12
(
a
). FIG.
12
(
c
) shows another example of the structure in FIG.
12
(
b
).
Referring first to Figs.
12
(
a
) and
12
(
b
), numeral
91
represents a glass substrate;
93
represents a cathode filament being a linear member;
951
represents a spacer (an auxiliary linear member) for supporting the filament
91
; and
952
represents a damper (an auxiliary linear member) for supporting the filament
93
.
One end of the filament
93
with the coil
931
is welded, together with the metal piece
921
, to a metal layer
92
(acting as a cathode mounting electrode), vapor-deposited on the substrate
91
. Using the linear (or rod-like) insulating (or glass) spacer
951
, a filament
93
is suspended so as to be elevated by a predetermined interval from the anode
96
(e.g. an anode electrode) on which a fluorescent substance is coated. To prevent the filament
93
from being contacted with the anode
96
due to vibration, a damper
952
(of the same material as the spacer
951
) is disposed on the substrate
91
. The spacer
951
and the damper
952
are directly bonded to the substrate
952
or are adhered to the insulating layer of the substrate
91
using an adhesive agent (e.g. fritted glass).
Referring to FIG.
12
(
c
), a conductive spacer
951
is securely adhered to the metal layer
941
bonded on the substrate
91
, using a conductive paste. Some spacers
951
are formed of a conductive material entirely or of an insulating material (e.g. glass) coated with a conductive material.
FIG. 13
shows an example of a grid formed of a metal wire, that is, the so-called wire grid. FIG.
13
(
a
) is a plan view partially illustrating a glass substrate on which a wire grid is mounted. FIG.
13
(
b
) is a cross-sectional view partially illustrating the portion taken along the line X
2
—X
2
of FIG.
13
(
a
). Like reference numerals are attached to the same constituent elements as those in FIG.
12
.
Referring to
Fig. 13
, numeral
97
represents a wire grid being a linear member;
953
represents a spacer being an auxiliary linear support member of the wire grid
97
; and
954
represents a damper being an auxiliary linear support member of the wire grid
97
.
The wire grid
97
is suspended between a cathode filament
93
and an anode
96
in the direction perpendicular to the filament
93
. The linear (or rod-like) spacer
953
of an insulating material (e.g. glass) holds the wire grid
97
at a predetermined elevation. One end of the wire grid
97
is securely bonded using the substrate
91
and the side plate
912
. In order to prevent the wire grid
97
from being contacted with the anode
96
due to vibration, the damper
954
of the same material as the spacer
953
is mounted on the substrate
91
. The spacer
953
and the damper
954
are directly bonded to the substrate
91
or are adhered to an insulating layer overlying the substrate
91
using an adhesive agent (e.g. fritted glass).
Conventionally, an adhesive agent (e.g. fritted glass or an adhesive paste) has been used to securely bond the auxiliary liner support members (e.g. spacers and dampers). However, the problem is that gas is generated from the adhesive agent inside an electron tube (such as a fluorescent display), thus decreasing the vacuum degree therein.
In order to mount and bond the spacer or damper on a base (or a substrate), an adhesive agent such as fritted glass is heated, softened, cooled and solidified. However, when the adhesive agent is re-heated and softened in the post step, the spacer or damper is often separated or displaced. For that reason, a suitable adhesive agent has to be chosen in consideration of the steps after bonding spacers and dampers. The temperature after the bonding has to be controlled carefully. Hence, the step of mounting spacers and dampers is troublesome and leads to high manufacturing costs. The substrate, the adhesive agent, the spacer, and the damper are required to have the same thermal expansion coefficient. The choice of such materials is limited.
The conventional linear or rod-like spacer, which has a smooth surface, often causes displacement of a liner member (such as a cathode filament or a wire grid). To prevent the displacement, some spacers have a recessed formed on the surface thereof and a filament or a wire grid is disposed in the recessed. However, this approach leads to an increase of the fabrication costs of a spacer.
SUMMARY OF THE INVENTION
The present invention is made to solve the above-mentioned problems.
An object of the invention is to provide an electron tube wherein auxiliary support members (e.g. spacers and dampers) used to subsidiarily support liner members (e.g. cathode filaments and wire grids) are bonded to a substrate, without using an adhesive agent. This structure can reduce the generation of gas causing a decrease in vacuum degree and simplify the process of mounting the auxiliary support member.
Particularly, the ultrasonic welding (ultrasonic bonding or ultrasonic wire bonding) can be preferably performed to heat a local area, that is, only the contact surface (interface) between the metal layer and the auxiliary metal support.
The objective of the present invention is achieved by an electron tube comprising a hermetic container having a first substrate on which an anode is formed and a second substrate confronting the first substrate; a metal layer formed inside the hermetic container; a linear member disposed in the hermetic container so as to confront the metal layer; at least one set of holders, disposed in the hermetic container, for holding the linear member; and metal auxiliary members, disposed between the linear member and the metal layer, each for supporting a linear member welded to the metal layer.
In the electron tube, the linear member comprises a cathode filament. Each of said auxiliary members comprises a spacer for a cathode filament. At least one set of the spacers is disposed between (inside) the holders.
In the electron tube, the linear member comprises a cathode filament. Each of the auxiliary members comprises a spacer for a cathode filament. The metal layer comprises a cathode mounting electrode.
In the electron tube, the linear member comprises a cathode filament. Each of the auxiliary members comprises a damper for a cathode filament. The damper is disposed between (inside) the holders.
In the electron tube, the linear member comprises a cathode filament. The auxiliary members comprise a spacer and a damper, for a cathode filament. At least one set of spacers is disposed between (inside) the holders. At least one damper is disposed between (inside) the spacers.
In the electron tube, the linear member comprises a wire grid. Each of the auxiliary members comprises a spacer for the wire grid. At least one set of spacers is disposed between (inside) the holders.
In the electron tube, the linear member comprises a grid wire. Each of the auxiliary members comprises a damper for the wire grid. The damper is disposed between (inside) the holders.
In the electron tube, the auxiliary members are disposed independently for each linear member.
In the electron tube, the welding is ultrasonic welding.
In the electron tube, the metal layer and the auxiliary members are made of the same metal material.
In the electron tube, the metal layer comprises a thin film layer.
In the electron tube, the
Kawasaki Hiroaki
Nohara Yasuhiro
Ogawa Yukio
Yonezawa Yoshihisa
Futaba Corporation
Tran Thuy Vinh
Wong Don
LandOfFree
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