Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – With bending – folding – winding – or wrapping means
Reexamination Certificate
1999-06-01
2002-04-16
Aftergut, Jeff H. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
With bending, folding, winding, or wrapping means
C156S475000, C156S488000
Reexamination Certificate
active
06371186
ABSTRACT:
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/JP97/03537 which has an International filing date of Oct. 1, 1997, which designated the United States of America.
FIELD OF THE INVENTION
The present invention relates to a technique to uniformly affix a functional film on a panel of a cathode-ray tube and the like, whose surface has a curvature in three dimensional directions. The present invention covers the panel provided by using this technique and method and apparatus for fabricating the panel. It is natural that the present invention may be applied to a case where the functional film is affixed to a panel surface having the curvature in two dimensional directions.
THE BACKGROUND ART
There is a case where a functional film is affixed to a surface of a panel presenting an image in a fabrication process of a cathode-ray tube, for example, or other display devices. That's because the functional film has an antistatic effect, a transmittance-support effect, an antireflection effect and the like.
There are two broad methods to affix the functional film on the panel surface of the cathode-ray tube.
The first method is, as shown in
FIG. 33
, using an ultraviolet hardening-type resin
2
D to bond a functional film
2
to a surface of a panel
1
A of a cathode-ray tube
1
. In this method, the ultraviolet hardening-type resin
2
D is applied to the surface of the panel
1
A of the cathode-ray tube
1
, and then the functional film
2
is put thereon and temporally affixed by pushing pressure of a roller
3
P. After temporally affixing the functional film
2
, the cathode-ray tube
1
is put into an ultraviolet irradiation furnace not shown, where the ultraviolet hardening-type resin
2
D is harden under ultraviolet irradiation, to bond the functional film
2
to the surface of the panel
1
A.
The second method is, as shown in
FIG. 34
, using the functional film
2
with an adhesive
2
A on its one side to bond the functional film
2
on the surface of the panel
1
A of the cathode-ray tube
1
by pushing pressure of the roller
3
P. In this method, a release paper
2
B (see
FIG. 35
) covering a surface of the adhesive
2
A on one side of the functional film
2
is removed before the functional film
2
is put on the surface of the panel
1
A of the cathode-ray tube
1
and the roller
3
P travels in a travelling direction while applying pressure to the functional film
2
, to bond the functional film
2
. In this case, a film with hard-coat layer
2
E formed on its one side surface, such as a polyethylene terephthalate (PET) film, is used as the functional film
2
as shown in the cross section of FIG.
35
.
In both the above two methods, a mechanism is provided, by which the pressure of the roller
3
P can be made almost uniform along the curvature of the surface of the panel
1
A in the roller travelling direction. For example, a biaxial interpolation mechanism having a curvature approximate to that relative to the roller travelling direction of the surface of the panel
1
A is fixed in a roller vertical direction and a roller travelling direction, to make the roller pressure uniform in response to the vertical variation of the panel surface. When a cylinder is used to generate a pushing force of the roller, a precision regulator for controlling the pressure is attached to the roller, to make the roller pressure uniform in response to the vertical variation of the panel surface. Further, if it is needed to control the pushing pressure to keep uniform with high precision, both the above biaxial interpolation mechanism for the roller vertical direction and the roller travelling direction and the precision regulator for controlling the pressure are used.
A problem common to the above two methods arises when the panel surface has a curvature in three dimensional directions, for example, in the cathode-ray tube.
For example, if the panel surface has such a shape as shown in
FIG. 36
, specifically, has a predetermined curvature in the XZ plane and a rectangular section in the YZ plane (defined as “a panel surface having a curvature in two directions”), it is possible to affix the functional film on the panel surface almost completely uniformly with the pressure of the roller having the above biaxial interpolation mechanism.
However, if the panel surface has such a spherical shape as shown in Fig. (
a
) and (
b
) of
37
(defined as “a panel surface having a curvature in three directions”), specifically, has curvatures both in the XZ plane and the YZ plane, when the functional film is pushed against the panel surface with the pushing roller
3
P having a length l as shown in (
b
) of
FIG. 37
, the highest pressure is applied at a top portion TOP of the panel surface in the Z direction, causing large variation in thickness of the roller
3
P, and on the other hand the variation in thickness of the roller
3
P decreases towards end portions EP
1
and EP
2
and the lowest pressure is applied at both the end portions.
In this case, if the roller pressure at the end portions EP
1
and EP
2
is increased in order to improve the method of affixing the functional film at the end portions EP
1
and EP
2
, the pressure applied at the top portion TOP becomes so high that it causes a damage to the panel surface. Therefore, the problem can not be solved by simply increasing the roller pressure.
Thus, in the method using the background-art tubular pushing roller, even if the mechanism that controls the roller pressure to be uniform along the curvature in the roller travelling direction is provided, there is a difference in pushing pressure at both the end portion sides of the panel surface in a plane perpendicular to the roller travelling direction, and that causes a problem that the functional film can not be affixed uniformly.
For example, in the method of bonding the functional film by using the ultraviolet hardening-type resin (hereinafter, referred to as “ultraviolet hardening-type resin bonding method”), since the panel of the cathode-ray tube has a complicate curvature in three dimensional directions, there is height difference in the vertical direction (the Z direction of
FIG. 37
) between the top position and the bottom position by several mm at both the end portion sides of the panel surface in the plane perpendicular to the roller travelling direction, to cause a large difference in roller pressure between the end portions. As a result, the ultraviolet hardening-type resin has a difference in thickness at both the end portion sides and air bubbles are likely to remain. Therefore, it is hard to affix the functional film uniformly with high quality.
Next, also in the method of bonding the functional film by using the adhesive (hereinafter, referred to as “adhesive bonding method”), the same problem as in the ultraviolet hardening-type resin bonding method is manifested. Specifically, if the panel surface of the cathode-ray tube has a curvature in three dimensional directions, there is a large difference in roller pressure between the top portion and the end portion sides of the panel surface in the plane perpendicular to the roller travelling direction. As a result, the functional film is not sufficiently bonded and air bubbles are left in a surface to which weak pressure is applied, and that makes it extremely difficult to uniformly affix the functional film.
In this respect, as background arts intended to affix the functional film on the panel surface, there are inventions disclosed in Japanese Patent Application Laid Open Gazettes 7-326289 and 7-45186. These inventions, however, do not recognize the above problem at all nor present any means to solve the above problem. Therefore, it is impossible to adopt the techniques of these inventions.
The above problem is not confined to the panel of the cathode-ray tube, but necessarily arises in affixing the functional film on the panel surface having a curvature in three dimensional directions. For example, similar problem may arise in affixing the functional film on a panel surface o
Koizumi Hiroshi
Miyamoto Hiroshi
Murata Mizuki
Okuda Hiroshi
Aftergut Jeff H.
Mitsubishi Denki & Kabushiki Kaisha
Musser Barbara J.
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