Electric lamp and discharge devices – Cathode ray tube – Ray generating or control
Reexamination Certificate
2000-05-11
2002-05-21
Kim, Robert H (Department: 2882)
Electric lamp and discharge devices
Cathode ray tube
Ray generating or control
C313S482000
Reexamination Certificate
active
06392335
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an electron gun fixer for use in a color cathode-ray tube and the like, and more particularly to an electron gun fixer which prevents damage and the like to the conductive film on the inner surface of a bulb neck.
2. Description of the Related Art
A cathode-ray tube has an electron gun fixer. A cathode-ray tube is disclosed, for example, in Japanese Patent Application Laid-Open (JP-A) No. 6-260111.
FIG. 1A
is a schematic diagram showing a conventional electron gun fixer in its entirety, and
FIG. 1B
is an enlarged schematic diagram showing the essential parts thereof. Hereinafter, the conventional electron gun fixer shown in
FIGS. 1A and 1B
will be referred to as a first conventional example.
The electron gun fixer
20
according to the first conventional example has a plurality of electrodes
21
coaxially arranged in sequence. These electrodes
21
are fixed and supported by an insulating support
22
to constitute an electron gun body
23
. A stem section
24
is arranged on the cathode-ray-tube-neck side of the electron gun body
23
. On the extremity of the electron gun body
23
opposite the stem section
24
is provided a shield cup
25
. The shield cup
25
has a plurality of bulb spacers
29
arranged at regular intervals on a concentric circle. The bulb spacers
29
have legs
27
which are fixed at one ends to the shield cup
25
via fixing portions
26
. On the other ends of the legs
27
are formed supporting portions
28
. Each of the supporting portions
28
is partly shaped into a spherical surface, and put into press contact with the inner surface of a bulb neck. The bulb spacers
29
are made of spring material.
In the first conventional example of such configuration, the plurality of bulb spacers
29
are balanced with each other by their spring forces while the electron gun fixer
20
is fixed in the bulb neck.
Now, description will be given of another conventional electron gun fixer. Hereinafter, this conventional electron gun fixer will be referred to as a second conventional example.
FIG. 2A
is a schematic diagram showing the conventional electron gun fixer (the second conventional example) in its entirety, and
FIG. 2B
is an enlarged schematic diagram shown the essential parts thereof.
The electron gun fixer
30
according to the second conventional example has a plurality of electrode
21
coaxially arranged in sequence. These electrodes
21
are fixed and supported by an insulating support
22
to constitute an electron gun body
23
. A stem section
24
is arranged on the cathode-ray-tube-neck side of the electron gun body
23
. On the extremity of the electron gun body
23
opposite the stem section
24
is provided a shield cup
25
. The shield cup
25
has a plurality of bulb spacers
35
arranged at regular intervals on a concentric circle. The bulb spacers
35
have legs
32
and
33
. The legs
32
are fixed at one ends to the shield cup
25
via fixing portions
31
, and the legs
33
are coupled to the legs
32
. The legs
33
extend in the directions at an acute angle to the extending directions of the legs
32
. Accordingly, the leg portions consisting of the legs
32
and
33
have a crooked shape. on the other ends of the legs
33
are formed supporting portions
34
. Each of the supporting portions
34
is partly shaped into a spherical surface, and put into press contact with the inner surface of a bulb neck. The bulb spacers
35
are made of spring material.
In the second conventional example of such configuration, the plurality of bulb spacers
35
are balanced with each other by their spring forces while the electron gun fixer
30
is fixed in the bulb neck.
FIGS. 3A through 3C
are schematic diagrams showing the details of the supporting portions in the conventional electron gun fixers.
FIG. 3B
is a cross-sectional view along the line A—A in
FIG. 3A
, and
FIG. 3C
is a cross-sectional view along the line B—B in FIG.
3
A.
As shown in
FIGS. 3A-3C
, the supporting portions
28
,
34
of the conventional bulb spacers
29
,
35
have an ellipsoidal shape. The supporting portions
28
,
34
have a constant radius of curvature of e.g. R
4
along the direction of insertion, and a constant radius of curvature of e.g. R
5
along the direction perpendicular thereto. Here, these radii of curvature R
4
and R
5
are relatively small. The reason for this is to prevent the cuts on the edges of the supporting portions
28
,
34
from coming into contact with the bulb neck inner surface to damage the bulb neck inner surface when the bulb spacers
29
,
35
are deformed before or during the insertion.
As compared to the bulb spacers
29
in the first conventional example, the bulb spacers
35
in the second conventional example have a wider range of motion of their leg portions made of spring material. This allows a reduction in spring rigidity. Accordingly, even when the gap between the bulb neck inner surface and the electron gun fixer is small, the second conventional example is easy to insert, and therefore is in greater use recently.
In inserting the electron gun fixers into the bulb neck of a cathode-ray tube, compressive forces are applied from the bulb neck inner surface to the bulb spacers' supporting portions
28
,
34
to compress the bulb spacers
29
,
35
, which spread out wider than the bulb neck inner surface if no force is applied thereto.
However, since the radii of curvature R
4
and R
5
are small as mentioned previously, the supporting portions
28
,
34
and the bulb neck inner surface practically make point contact with each other as shown by a contact zone
41
in FIG.
3
A. In other words, the supporting portions and the bulb neck are very small in contact area. Accordingly, the contact points on the bulb neck inner surface are subjected to excessive pressures. This produces the problem that the conductive film on the inner surface of the bulb neck is damaged and peeled off on the occasion when the electron gun fixer
20
,
30
is inserted into the bulb neck. In addition, simply inserting the electron gun fixer
20
,
30
along the tube axis linearly does not always provide a match between the scanning direction on the screen and the RGB alignment of the electron gun fixer
20
,
30
. Therefore, the insertion is sometimes followed by rotation for directional adjustment. This also produces the problem of damaging and peeling the conductive film on the inner surface of the bulb neck due to the same reason.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an electron gun fixer having bulb spacers that can prevent the conductive film on the inner surface of the bulb neck from being damaged and peeled off in the steps of inserting the electron gun fixer along the tube axis linearly and rotating the same.
According to one aspect of the present invention, an electron gun fixer comprises bulb spacers fixed to an electron gun to be inserted into a bulb neck. Each of these bulb spacers has a supporting portion to be put into press contact with the inner surface of the bulb neck. The expression “R
1
≧R
2
>R
3
” holds for this support portion, where R
1
is the radius of curvature in the cross section along the direction of insertion of the electron gun into the bulb neck, R
2
is the radius of curvature of a peripheral part in the cross section perpendicular to the direction of insertion, and R
3
is the radius of curvature of the remaining parts in the cross section perpendicular to the direction of insertion. R
2
is substantially equal to the radius of curvature R
0
of the bulb neck.
The supporting portion of each bulb spacer in the present invention has the spherical surface whose radius of curvature R
2
in the region excepting the rims in the direction perpendicular to the direction of insertion of the electron gun fixer is almost the same as the radius of curvature of the bulb neck inner surface. Therefore, the contact portion between the bulb spacer's supporting portion and the bulb neck inner s
Kim Robert H
McGinn & Gibb PLLC
NEC Corporation
Yun Jurie
LandOfFree
Electron gun fixer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electron gun fixer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electron gun fixer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2864992