Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-10-06
2001-08-07
Foster, Jim (Department: 3728)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C206S714000
Reexamination Certificate
active
06270614
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a carrier tape used for packing surface-mounting type electronic devices and a method for fabricating such a carrier tape. The present invention also relates to a taped package having electronic devices packed by such a carrier tape.
2. Description of the Related Art
Conventionally, electronic devices, and in particular surface-mounting type electronic devices, are sometimes packed using trays or embossed type carrier tapes, and the thus formed packages are shipped to users. The users use the electronic devices in such packages in automated mounting machines to mount the electronic devices to the surface of the printed wiring boards or the like.
FIG. 14
of the attached drawings is a perspective view of the tray. The tray has a plurality of square cavities (pockets)
41
arranged in a matrix pattern, so that the electronic devices can be accommodated in the pockets
41
.
FIG. 15
of the attached drawings is a perspective view of the embossed type carrier tape. In this figure, the numeral
50
shows the embossed type carrier tape, the numeral
60
shows a top cover tape, and the numeral
70
shows a reel. The embossed type carrier tape
50
has a row of pockets
51
and connecting wall portions
52
interconnecting adjacent pockets
51
. The embossed type carrier tape
50
is made from a plastic sheet (tape) which is embossed by vacuum forming or heat pressing, to form the pockets
51
. The carrier tape
50
also has feed holes
53
.
The package of electronic devices is used as follows; the electronic devices are put in the pockets
51
of the carrier tape
50
, the pockets
51
are covered by the top cover sheet
60
bonded to the carrier tape
50
, and the carrier tape
50
is wound on the reel
70
. The manufacturer then ships the reel
70
as a package, and the user thus uses the reel
70
in an automated mounting machine to mount the electronic devices to the surface of a printed wiring board or the like. After the mounting operation, the carrier tape
50
is severed into small pieces by a cutter attached to the automated mounting machine, and the severed carrier tape
50
is disposed of.
In the mounting operation of the electronic devices to the surface of the printed wiring board by the automated mounting machine, it is generally recognized that the electronic devices packed in the carrier tape can be mounted to the printed wiring board at a considerably faster speed than that of the electronic devices packed in the tray. However, since the embossed type carrier tape
50
is made from a plastic sheet having a uniform thickness and the pockets
51
are embossed by vacuum forming or heat pressing, there are problems that if a relatively thick plastic sheet is used, it is not easy to wind the embossed type carrier tape
50
on the reel
70
, and if the relatively thin plastic sheet is used, the strength of the pockets
51
is insufficient to reliably accommodate, in particular, large articles, so that the bottoms of the pockets may collapse while the embossed type carrier tape is wound on the reel, to cause the articles in the pockets to be damaged (for example, the external leads may be deformed in the case of a QFP (Quad Flat Package) type LSI). In addition, it is difficult to accurately form the pockets which are designed to accommodate larger articles. Therefore, conventionally, there is a problem that larger articles must be packed in the trays.
FIG. 13
in the attached drawings is a side view of the package, illustrating the problem of the prior art. This figure shows that the embossed type carrier tape is wound on the reel and the bottoms of the pockets located on the outer side of the bent portion of the tape are collapsed.
SUMMARY OF THE INVENTION
The object of the present invention is to solve the above described problems and to provide a carrier tape and a method for fabricating such a carrier tape, which can be wound onto a reel without difficulty even if the carrier tape is intended to pack relatively large articles.
Another object of the present invention is to provide a carrier tape and a method for such a carrier tape, in which the bottoms of the pockets are strengthened to prevent the articles accommodated in the pockets from being damaged.
A further object of the present invention is to provide a taped package comprising a carrier tape and articles accommodated in the pockets of the carrier tape.
According to the present invention, there is provided a carrier tape having a row of pockets comprising bottom walls and side walls for accommodating articles therein, and connecting walls interconnecting the side walls of adjacent pockets, at least the bottom walls having a thickness greater than a thickness of the connecting walls to reinforce at least the bottom walls.
Preferably, the tape comprises a biodegradable plastic or an electrically conductive plastic. Preferably, the tape comprises a first region including at least the pocket and a second region, the first region comprising an electrically conductive plastic, the second region comprising an electrically non-conductive plastic.
Preferably, the pocket has a plurality of through holes at the bottom wall. Also, preferably, the tape has a region to which a top cover tape is to be bonded after an article is accommodated in the pocket, the surface of the region being roughened. Also, preferably, the pockets comprise a plurality of kinds of pockets differing in at least one of a shape and a dimension. Also, preferably, the tape has a hole pattern at or adjacent to a particular one of the pockets. Also, preferably, the tape has at least one of through holes, notches, and thin wall portions arranged at a longitudinally constant pitch so that a widthwise cross-sectional area of the tape is reduced.
According to another aspect of the present invention, there is provided a method for fabricating a carrier tape having a row of pockets. The method comprising the steps of forming carrier tape sections by injection molding so that each of the carrier tape sections has at least one pocket for accommodating an article therein, and joining the carrier tape sections in the form of a tape.
Preferably, the carrier tape sections have respective sides, and wherein the first carrier tape section is first injection molded, the second carrier tape section is then injection molded such that one side of the first carrier tape section is in contact with one side of the second carrier tape section, and the further one carrier tape section is then injection molded such that one side of the second carrier tape section is in contact with one side of the further one carrier tape section, whereby the carrier tape sections are successively joined together.
Preferably, a plurality of kinds of carrier tape sections differing in at least one of a shape and a dimension are formed by injection molding, and the carrier tape sections are joined in the form of a tape.
Preferably, the carrier tape sections are formed by two-color injection molding so that each of the carrier tape sections comprises a first region of an electrically conductive plastic and a second region of an electrically non-conductive plastic.
According to a further aspect of the present invention, there is provided a taped package comprising a carrier tape arranged in the above described manner, and articles accommodated in the pockets of the carrier tape.
In the present invention, the bottom walls of the carrier tape are made thicker to reinforce the bottom walls so that the bottoms of the pockets are strengthened to prevent the articles accommodated in the pockets from being damaged, and on the other hand, the connecting walls are maintained thinner, so that the carrier tape can be easily wound on a reel without difficulty. In the conventional embossed type carrier tape, it is difficult to partially increase the thickness of the carrier tape which is fabricated by vacuum forming or heat pressing, but according to the present invention, it is possible to partially increase the thickness of
Ando Yukio
Kanai Osamu
Kobayashi Kazuo
Naito Fuminori
Foster Jim
Fujitsu Limited
Staas & Halsey , LLP
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