CRT socket

Details CRT socket CRT socket

2002-11-22

2004-06-08

Nguyen, Khiem (Department: 2839)

Electrical connectors

Including arc suppressing or extinguishing means

Lamp or electron tube socket

C439S683000

Reexamination Certificate

active

06746259

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to a CRT (cathode ray tube) socket for connecting with CRT of color TV or display, where the structure of the CRT socket is simplified and miniaturized.
RELATED PRIOR ART
In the CRT of color TV or display, along with increase in size and precision, dual-focus tube having plural of focus means is widely used so as to correspond to the high voltage of the focus voltage and to make CRT a larger viewing-angle and more miniaturized. In order to obtain high resolution image on whole area of the screen, the voltage difference applied between a plurality of focus pins is increased and a high frequency dynamic voltage waveform is repeatedly applied to the focus pins.
In the CRT socket for using in multiple-focus tube, in order to prevent abnormal discharge energy generated in the CRT from damaging circuit elements, each discharge gap is generally built in each focus portion.
Hereinafter using an example for explanation the general structure of the CRT socket for using in dual-focus tube.
FIG. 8
is a perspective view of the CRT socket
100
of the prior art,
FIG. 7
is a sectional view of the main portion of the CRT socket
100
, and
FIG. 6
shows the structure of the main, viewing from inside of the outer case.
The CRT socket
100
comprises an annular portion
102
, an outer case
103
, a base portion
104
, and a cylindrical center opening
105
. The annular portion
102
is formed by concentrically positioning a plurality of signal contact openings
106
on the outside of the cylindrical center opening
105
formed by resin injected molded, positioning signal contact housings
161
inside the annular portion
102
, positioning signal contacts
162
formed of conductive metallic plate in the signal contact housings
161
, and arranging a small predetermined discharge gap to separate from a grounded metal
164
, which, after being applied with abnormal voltage, will discharge to outside.
The outer case
103
comprises the focus contact openings
107
a
and
107
b
for connecting focus pins inserted to apply high voltage, and the base portion
104
covered by resin.
In the concentric position of the annular portion
102
, the focus contact housings
117
a
and
117
b
are concavely positioned in the inside of the outer case, and focus contacts
170
a
and
170
b
are provided therein. Also provided therein are grounded terminals b
11
and b
21
of grounded electrodes b
1
, b
2
, which are provided with predetermined high voltage discharge gaps H
1
and H
2
.
Focus contact openings
107
a
and
107
b
are positioned on the surface corresponding to the focus contact housings.
As shown in
FIG. 7
, terminal pins
22
a
,
22
b
to which 5-10 KV high voltage is applied for focus in CRT
20
are connected to the focus contact
170
a
,
170
b
, and a terminal pin
23
to which a plurality of signals with 0-100V low voltage are applied is connected to the signal contact
162
.
The grounded terminals b
11
, b
21
and the connecting terminal
163
for the signal contact are connected to a circuit board
21
by solder welding.
As shown in
FIG. 6
, i.e., the structure of focus portion viewing from inner side of the outer case, in case of having a plurality of focus portions, in the prior art, the focus contacts
170
a
,
170
b
for connecting to each terminal pin are provided with high voltage discharge electrodes a
1
, a
2
, and are respectively provided with the grounded electrodes b
1
, b
2
opposite thereto and the grounded terminal b
11
, b
21
.
Because the high voltage discharge electrodes a
1
, a
2
and the grounded electrodes b
1
, b
2
are necessary for each focus terminal to form high voltage discharge gaps H
1
, H
2
, the structure of CRT socket becomes large and the elements used therein are also increased.
Due to the above problems, the applicant of the invention has disclosed a structure of CRT socket as shown in
FIG. 5
(Japanese patent application 2001-285531).
For connecting to a first focus pin
22
a
on one side of the CRT, a first focus contact
70
a
is provided where one of its ends is opposite to a first focus contact opening
7
a
, and the other end is provided with a wiring contact
71
a.
A low voltage discharge electrode A
1
is pressed connected to another end of the electrode A of a second focus contact
70
b
, a low voltage discharge electrode FA is position on the first focus contact
70
a
, and a low voltage discharge gap L
1
is formed therebetween.
For connecting to a second focus pin
22
b
on the other side of CRT, a second focus contact
70
b
is provided where one of its ends is opposite to the second focus contact opening
7
b
. The other end of the second focus contact
70
b
has a wiring connect portion
71
b
, and is pressed connected to a connect portion
72
b
of the second focus contact and a connect portion AW of the focus contact of the electrode A.
The electrode A is opposite to grounded electrode B with a predetermined high voltage discharge gap H intervened therebetween, and the grounded electrode B is connected to the grounded terminal B
1
.
Here the high voltage discharge gap H is determined along with the abnormal discharge energy. Usually, there are 5-10 KV high voltage applied to the terminal pin for focus, and thus what is defined shall be higher more than 3-5 KV.
The low voltage discharge gap L
1
, in consideration of the voltage difference or dynamic voltage variation of two terminal pins or focus, is usually set as 2-3 KV.
In the prior art, as shown in
FIG. 6
, when an abnormal discharge is happened from the anode of the CRT, for those through high voltage discharge gaps H
1
, H
2
to flow the discharge energy to the ground in order to protect the circuit elements in the circuit board, the focus contact structure shown in
FIG. 5
is used. That is, when the second focus pin
22
b
generates abnormal discharge, this abnormal discharge will flow through the high voltage discharge gap H between the electrode A pressed connected to the second focus contact
70
b
of the second focus pin and the grounded electrode B to the ground.
When an abnormal discharge is generated in the first focus pin
22
a
, the abnormal discharge will flow through the low voltage discharge gap L
1
between the first focus contact
70
a
and the electrode A connected to the second focus contact
70
b
to the electrode A, and flows through the high voltage discharge gap H between the electrodes A and B, so as to protect the circuit elements on the circuit board.
Therefore, the first focus contact may use the electrode A through the low voltage discharge gap L
1
, the numbers of elements are reduced, and thus the CRT socket can be miniaturized.
The focus contact may directly connect to the electrode A. By providing the low voltage discharge gap L
1
between the other focus contacts and the electrode A, the voltage difference or the dynamic voltage variation between the focus pins can be absorbed to some degree, and the electrode A is used commonly.
However, in comparison with independently providing high voltage discharge gap so as to make grounded electrode b opposite to the electrode a as shown in
FIG. 6
, it is inevitable to narrow the withstanding voltage difference between focus pins. Because the electric connect situation and the discharge wiring of focus pins are different from each other, the discharge voltage of every focus pins just before discharge still need to be improved to be the same.
SUMMARY OF THE INVENTION
In view of the above, the Japanese patent application 2001-285531 filed by the applicant shall be further improved. The invention aims at this and provides an effectively miniaturized CRT socket capable of assuring large withstanding discharge voltage difference between the focus pins of the CRT socket, unifying the voltage just before discharge, and simplifying the structure of the high voltage discharge gap.
The invention relates to a CRT (cathode ray tube) socket to which a plurality of focus means of the CRT are connected, characterized in comprising electrodes (FA) each positioned on each focu

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