Radiant energy – Photocells; circuits and apparatus – Housings
Reexamination Certificate
2002-04-04
2004-01-13
Porta, David (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Housings
C250S551000, C257S433000
Reexamination Certificate
active
06677580
ABSTRACT:
TECHNICAL FIELD
This invention relates to a photo-interrupter and a semiconductor device using the same, and more particularly to a photo-interrupter which can mount a light-emitting device and a light receiving device in a concave case in an inexpensive configuration and stably couple hooks for hooking a base plate with the left and right outer surfaces of the case, and a semiconductor device such as an interrupter which is attached into a hole of the base plate, particularly a semiconductor device characterized by a structure of its attaching legs and provided with a floatage suppressing piece for suppressing the floatage in a state attached to the base plate.
BACKGROUND ART
A photo-interrupter with a light-emitting device and a light-receiving device oppositely arranged apart from each other by a predetermined distance and integrated to each other detects whether or not there is an object between the light-emitting device and the light-receiving device on the basis of a change in an amount of light received by the light-receiving device. Such a photo-interrupter houses the light-emitting device and light-receiving device molded by translucent synthetic resin within a case molded by opaque synthetic resin.
FIG. 3
is a schematic longitudinal front view showing an example of a conventional photo-interrupter. In
FIG. 3
, reference numeral
20
denotes a photo-interrupter;
2
a case molded in a concave shape by opaque synthetic resin; and
3
a
,
3
b
hooks for hooking a base plate which are coupled with outer surfaces
2
x
and
2
y
located on left and right sides of the concave case
2
, extended horizontally and bent vertically to form hook pieces
4
a
and
4
b
for hooking the base plate at their tips. These hooks
3
a
and
3
b
are molded by opaque synthetic resin integrally to the concave case
2
.
Reference numerals
5
a
and
5
b
denote openings formed on left and right inner surfaces
2
a
and
2
b
of the concave case
2
which are opposite to each other. A light-emitting device
6
and a light-receiving device
7
are housed in spaces within the case
2
. The light-emitting device
6
is provided with a lens
6
a
which projects forward. The light-receiving device
7
is provided with a lens
7
a
which projects forward.
The lens
6
a
and lens
7
a
are arranged oppositely to each other in the openings
5
a
and
5
b
so that the output light emitted from the light-emitting device
6
is received by the light-receiving device
7
. As seen from a perspective view of
FIG. 4
, the opening
5
a
is formed in a groove shape having a prescribed length from the upper surface
2
s
. Reference numeral
5
x
denotes an end face of the opening
5
a
. The opening
5
b
is also formed in the same shape as that of the opening
5
a.
Numeral
6
b
denotes a lead terminal of the light-emitting device
6
, whereas numeral
7
b
denotes a lead terminal of the light-receiving device
7
. Numeral
8
a
denotes an adhesive which fixes the light-emitting device
6
to the side wall of the case
2
, whereas numeral
8
b
denotes an adhesive which fixes the light-receiving device
7
to the side wall of the case
2
.
A configuration in which the light-emitting device
6
and the light-receiving device
7
are fixed to the side walls of the case
2
using the adhesives
8
a
and
8
b
presents a problem of increasing the number of man-hours of assembling the photo-interrupter
20
. Application of a small amount of adhesive will peel the light-emitting device
6
and light-receiving device
7
. Therefore, the amount of the applied adhesive must be controlled appropriately. This presents a problem of making the process management complicated.
In order to overcome such an inconvenience, a photo-interrupter having a configuration in which the light-emitting device
6
and the light-receiving device
7
anchored to the case using pallets formed inside the case
2
has been developed.
FIG. 5
is a schematic longitudinal front view of an example in which the light-emitting device
6
and the light-receiving element
7
are anchored using pallets
8
x and
8
y formed inside the case
2
. In
FIG. 5
, like reference numerals refer to like parts in FIG.
3
.
Where such pallets are formed inside the case
2
, the bottoms of the light-emitting device
6
and the light-receiving device
7
are aligned with the pallets by warping the portion sandwiched by two slits passing through the side walls from the outer surfaces
2
x
and
2
y
of the concave case to the internal spaces.
FIG. 6
is a schematic perspective view showing an example in which the above two slits
9
having a prescribed length from the bottom of the case
2
are formed in the outer surface
2
x
. The slits
9
has a depth which reaches the space in which the light-emitting device
6
is housed inside the case
2
through the side wall. Similar slits are also formed in the outer surface
2
y
on the side in which the light-receiving device
7
is housed. With the light-emitting device
6
inserted into the internal space of the case
2
, the portion of the outer surface
2
x
sandwiched by the two slits
9
is swung in a direction of arrow A so that it warps. Then, the light-emitting device
6
is anchored by the pallet formed inside the case.
FIG. 8
is a perspective view showing an example in which two slits
10
each having a prescribed length from the upper surface
2
s
of the case
2
are formed in the outer surface
2
x
to provide a portion
2
c
sandwiched therebetween.
FIG. 10
is a perspective view showing an example in which two slits
11
each having a prescribed length are formed centrally in the outer surface
2
x.
In the examples of
FIGS. 8 and 10
, the same slits as formed in the outer surface
2
x
are formed in the outer surface
2
y.
The configuration as illustrated in
FIG. 5
in which the pallets for anchoring are formed inside the case has presented a problem that the mold is generally complicate. Further, as illustrated in
FIG. 6
, when the slits each having a prescribed length from the bottom of the case are formed in the left and right outer surfaces, as seen from a perspective view of
FIG. 7
, where the hooks
3
a
and
3
b
(
3
b
not shown) for hooking the base plate are provided on the outer surfaces
2
x
and
2
y
to support the weight of the photo-interrupter, these hooks are coupled with the outer surfaces aside from the positions where the slits are formed.
This fact presented a problem that the assembled structure provides reduced mechanical strength and poor stability. In addition, the coupling portion between the hook for hooking the base plate and the outer surface of the case is unstable. This also presented a problem that the position of the hook piece, formed at the tip of the hook, relative to the base plate is not stable.
Further, as illustrated in
FIG. 8
, where two slits
10
each having a prescribed length from the upper surface
2
s
of the case
2
are formed, the hooks for hooking the base plate are formed on the left and right outer surfaces. This make it impossible to extend the slits downward. Therefore, as seen from a partial longitudinal front view of
FIG. 9
, where the light emitting device
6
inserted into the case
2
from a direction of arrow B is anchored by the pallet
8
x
provided inside the case
2
, the portion
2
c
sandwiched between the two slits
10
is shortened so that it does not warp sufficiently in a direction of arrow. This presented a problem that the operation of anchoring the light-emitting device
6
becomes difficult. Likewise, the operation of anchoring the light-receiving device became difficult.
As seen from
FIG. 10
, where two slits each having a prescribed length are formed centrally in the left and right outer surfaces of the concave case, a sliding mold is required so that the mold structure becomes complicated. This presented a problem of an increase in the product price.
Further, traditionally, the semiconductor device such as a photo-interrupter has been attached to the base plate in such a manner that the attaching legs provided o
Sano Masashi
Suzuki Nobuaki
Lee Patrick J.
Porta David
Rohm & Co., Ltd.
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