Glass manufacturing – Processes of manufacturing fibers – filaments – or preforms – Process of manufacturing optical fibers – waveguides – or...
Reexamination Certificate
1999-07-07
2003-01-28
Colaianni, Michael (Department: 1731)
Glass manufacturing
Processes of manufacturing fibers, filaments, or preforms
Process of manufacturing optical fibers, waveguides, or...
C065S404000, C065S406000, C065S408000, C065S038000, C065S044000, C065S055000, C065S066000, C065S102000, C264S001210, C264S001250, C264S002500, C264S219000, C264S220000, C425S398000, C425S399000, C425S412000
Reexamination Certificate
active
06510709
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a shaping mold, an optical fiber guide block, processes for the production thereof and an optical fiber array. More specifically, it relates to a shaping mold for producing an optical fiber guide block which permits highly accurate positioning and fixing of all of a plurality of optical fibers, a process for the production thereof, an optical fiber guide block having the above excellent properties, a process for the production thereof, and an optical fiber array in which all of a plurality of optical fibers are highly accurately positioned and fixed in an optical fiber guide block.
2. Description of Related Art
For optically connecting a plurality of optical fibers to a plurality of optical fibers or connecting a plurality of optical fibers to one or a plurality of optical parts, it is desirable to carry out highly accurate pre-positioning and pre-fixing of each of optical fibers which are to be optically connected. For this purpose, many optical fiber guide blocks are used. An optical fiber guide block is a member for highly accurately pre-positioning and pre-fixing, for example, end portions of a plurality of optical fibers for optically connecting a plurality of the optical fibers to optical fibers or optical part(s).
The optical fiber guide block is a thin-sheet-shaped part having a predetermined number of optical fiber fitting portions formed on one surface thereof, which optical fiber fitting portions are used for positioning and fixing end portions of optical fibers. The optical fiber fitting portions are generally formed of grooves having a predetermined width and a predetermined depth each. The optical fiber guide block is largely classified into the following two types (1) and (2).
(1) An optical fiber guide block which is a thin-sheet-shaped member having a predetermined number of optical fiber fitting portions formed on one surface thereof, each optical fiber fitting portion extending from one side of the “one surface” to the other side or from the one side to predetermined positions on the “one surface”.
(2) An optical fiber guide block having an optical fiber fixing region where optical fiber fitting portions are formed on the upper surface thereof and a low-level region having its upper surface positioned at a lower level than the level of the upper surface of the optical fiber fixing region.
In the optical fiber guide block of the above type (2), a predetermined number of optical fiber fitting portions are formed on the upper surface of the optical fiber fixing region, and each optical fiber fitting portion extends from a side (boundary) between the optical fiber fixing region and the low-level region to the other side which is opposite to the boundary side and is on the upper surface of the optical fiber fixing region, or from the boundary side to a predetermined position on the above upper surface. The low-level region works as a setting on which the coating portion of coated optical fibers (optical fibers protected with a coating) such as an optical fiber tape is to be fixed.
Conventionally, attempts have been made to produce optical fiber guide blocks of the above types by an etching method or a cutting method, while attempts are being actively made to produce them by a mold-shaping method in recent years. The mold-shaping method is promising as a method capable of providing optical fiber guide blocks having high accuracy of an external form and high accuracy of optical fiber fitting portions and having high stability with regard to the above accuracy properties with high productivity at low costs.
When an optical fiber guide block having a plurality of optical fiber fitting portions is produced by a mold-shaping method, conventionally, there is used a shaping mold having transfer shaping surfaces which are used for shaping the above optical fiber fitting portions and upper surfaces around a region of the optical fiber fitting portions (the above upper surfaces will be referred to as “sided upper surfaces” hereinafter). The above conventional shaping mold has a cross section, for example, as shown in FIG.
11
(
a
). FIG.
11
(
a
) is a schematic cross-sectional view of one example of conventional shaping molds. A shaping mold
80
shown in FIG.
11
(
a
) has convex portions
81
for shaping a predetermined number of optical fiber fitting portions, and bottoms between adjacent convex portions
81
are at the same level as the level of shaping surfaces
82
a
and
82
b
to be used for shaping the sided upper surfaces (for example, see
FIG. 4
of JP-A-8-292332).
When the above shaping mold
80
is used, an optical fiber guide block shown in FIG.
11
(
b
) is obtained. FIG.
11
(
b
) shows a schematic cross-sectional view of an optical fiber guide block
88
obtained by means of the shaping mold shown in FIG.
11
(
a
). The optical fiber guide block
88
has a structure in which peak surfaces
86
present in boundaries between adjacent optical fiber fitting portions are substantially at the same level as the level of sided upper surfaces
87
a
and
87
b.
Meanwhile, for complying with an increased density of an optical circuit, etc., in recent years, there is increasingly demanded an optical fiber array in which a plurality of optical fibers are positioned and fixed at intervals which are as close as possible. The above optical fiber array has an optical fiber guide block, a plurality of optical fibers positioned and fixed on the optical fiber guide block and a pressing member used for pressing and fixing the optical fibers to optical fiber fitting portions. With the above increasing demand, it is also increasingly demanded to form optical fiber fitting portions at intervals as close as possible in an optical fiber guide block for constituting the above optical fiber array.
As the pitch of a plurality of optical fiber fitting portions is decreased when the optical fiber fitting portions are formed, theoretically, there can be produced an optical fiber guide block which permits positioning and fixing of a predetermined number of the optical fibers in a state where circumferential surfaces of optical fibers located side by side are in contact with each other. When the circumferential surfaces of adjacent optical fibers are in contact with each other, however, there is no lubricity caused between the circumferential surfaces of the adjacent optical fibers, and it is therefore difficult to position and fix the optical fibers. Practically, therefore, it is desirable to give a gap of approximately several &mgr;m between the circumferential surfaces of the adjacent optical fibers.
When a plurality of optical fibers are positioned and fixed in a state where the circumferential surfaces of adjacent optical fibers are in contact with each other or in a state where the circumferential surfaces of adjacent optical fibers are apart from each other by the above gap of several &mgr;m, and when the peaks of boundary portions between the adjacent optical fiber fitting portions are substantially at the same level as the level of the sided upper surfaces, the amount of projection of the circumferential surfaces of the optical fibers (height of projected portions) measured from the level of the sided upper surfaces is large.
When an optical fiber array is produced by fitting a plurality of optical fibers in optical fiber fitting portions and pressing and fixing the optical fibers with a pressing member, therefore, there is formed a large gap between the optical fiber guide block and the pressing member, and an adhesive layer formed in the gap therefore has a large thickness. As a result, the adhesive layer is liable to peel off due to curing contraction or due to swelling caused by the absorption of water, which causes a problem that the reliability of the optical fiber array decreases. Further, each of optical fiber supporting positions of the optical fiber fitting portions is considerably low. That is, when cross sections of each optical fiber fitting portion and each optical fiber are take
Kagami Kaoru
Ohgami You
Yamashita Teruo
Colaianni Michael
Hoya Corporation
Nixon & Vanderhye
LandOfFree
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