Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
1999-09-21
2001-01-09
Lee, John R. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C438S025000, C438S028000
Reexamination Certificate
active
06172357
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a photoelectric tilt-detecting sensor for detecting the presence or absence of tilting of an object to be detected, and a method of fabricating the same.
There have been known photo-interrupters for use in various applications of optical sensors. The photo-interrupter generally includes a light-emitting element for emitting light, and a light-receiving element for receiving the light emitted therefrom. The photo-interrupter is utilized to determine whether or not a certain object is present between these two optical elements, by detection of an electric current generated from reception of light by the light-receiving element.
The conventionally known photoelectric tilt-detecting sensor, as shown in
FIG. 13
, comprising a photo-interrupter
31
formed by a light-emitting element
31
a
and a light-receiving element
31
b
. The photo-interrupter
31
is built in a lower case
32
for the sensor formed of a resin, with an upper case
33
fitted over the lower case
32
. The upper case
33
has opposite bearing supports
33
a
extending therefrom toward the inner side of the lower case
32
. A fan-shaped light-shielding plate
34
is pivotally supported on bearings
33
b
for swinging between the light-emitting element
31
a
and the light-receiving element
31
b.
In the tilt-detecting sensor thus constructed, the light-shielding plate
34
ordinarily rests at its lowest position due to the action of gravity. To use the tilt-detecting sensor, it is mounted or fixed on an object to be detected, not shown. While the tilting angle is smaller than a certain value, the light emitted from the light-emitting element
31
a
is shielded by the light-shielding plate
34
and no light is transmitted to the light-receiving element
31
b
. However, if the angle of tilting exceeds the above angle, the light-shielding plate
34
goes out between the light-emitting element
31
a
and the light-receiving element
31
b
. As a result, the light emitted is transmitted to the light-receiving element
31
b
. The light-receiving element
31
b
, upon reception of light, generates an electric current to supply the same through lead terminals thereof, making possible detection of the tilting for the object to be detected.
Meanwhile, there is increase in demands of offering sensors integral with a photo-interrupter, as the technology in the art of semiconductor or optical devices advances. On the other hand, it is strongly demanded that the number of parts be reduced for making such devices, together with simplification of fabrication processes.
However, the conventional tilt-detecting sensor necessitates bearings
33
b
on the upper case
33
for assembling a light-shielding plate
34
therein. Besides the light-shielding plate
34
has to be assembled by inserting its support axis into the respective bearings
33
b
. This light-shielding plate
34
must be formed relatively complicated in shape, or otherwise assembled with a separate support shaft, thus incurring complexity in fabrication processes. In practical, there is difficulty of reducing the number of parts used and simplifying the fabrication processes.
Further, in the conventional tilt-detecting sensor, there is a problem left in smoothness of movement of the light-shielding plate which is in pivotal support by the opposite bearings. The light-shielding plate thus mechanically structured is apt to lose its smoothness in movement, particularly where an external impact force be applied or tilting is in other direction than the direction being detected.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a phtoelectric tilt-detecting sensor which, while simple in structure, is to smoothly actuate in detection of tilting.
It is another object of the invention to make possible detection of direction to which an object to be detected is tilted.
It is a further object of the invention to provide reliability in structure, preventing disengagement of a lid from the main body.
It is a still further object of the invention to provide a method for fabricating a photoelectric tilt-detecting sensor through simplified processes.
According to a first aspect of the present invention, there is provided a photoelectric tilt-detecting sensor comprising:
a light-emitting element for emitting light;
a light-receiving element for receiving the light emitted from the light-emitting element;
a main body molding the light-emitting element and the light-receiving element in an opposed relation, the main body having slant surfaces in a lower portion thereof to define a space therein;
a spherical ball accommodated in the space so as to be movable along the slant surfaces;
a lid fitted over the main body to enclose the space; and
a ball guide means provided in the slant surfaces for guiding the movement of the spherical ball.
Therefore, the ball guide means serves as a guide for stable movement of the spherical ball along the slant surfaces. Besides, the ball guide means acts to prevent the light from traveling around the spherical ball and reaching the light-receiving element, sensibly detecting the inclination of an object to be detected and providing reliability in tilt detection.
It is preferred that the slant surface have a bottom formed continuous therewith, the bottom is of a curved surface having a radius corresponding to that of the spherical ball with respect to a direction of the slant surface. With such a structure, the spherical ball rests stably on the bottom when the sensor is not tilted.
It is also preferred that an additional ball guide means is further provided in an inner surface of the lid. This further reduces the traveling-around of light emitted.
It is further preferred that additional light-emitting element and light-receiving element are further provided at such positions that no light is transmitted from the additional light-emitting element to the additional light-receiving element due to shielding of light by the spherical ball when the spherical ball rests on the slant surface other than the bottom. This makes possible detection of the direction to which the tilting takes place.
According to a second aspect of the present invention, there is provided a photoelectric tilt-detecting sensor comprising:
a light-emitting element for emitting light;
a light-receiving element for receiving the light emitted from the light-emitting element;
a main body molding the light-emitting element and the light-receiving element in an opposed relation, the main body having slant surfaces in a lower portion thereof to define a space therein;
a spherical ball accommodated in the space so as to be movable along the slant surfaces; and
a lid fitted over the main body to enclose the space, wherein the lid has one end thereof connected by integral forming to the main body and the other end thereof engaged with the main body.
It is therefore possible to prevent the lid from disengaging from the main body, thereby providing the reliability of structure.
According to a third aspect of the present invention, there is provided a method of fabricating a photoelectric tilt-detecting sensor having a light-emitting element and a light-receiving element provided in an opposed relation so as to accommodate a spherical ball therebetween, comprising the steps of:
preparing forming dies, the dies has a cavity for forming a main body and a lid connected at one end thereof to the main body;
placing a light-emitting element and a light-receiving element between the dies;
filling a resin into the cavity of the dies to provide a main body and a lid in one body and slant surfaces defining a space between the light-emitting element and the light-receiving element in the main body;
inserting a spherical ball into the space of the main body after setting of the resin; and
bending the lid for engagement at the other end thereof with the main body.
It is accordingly possible to fabricate a photoelectric tilt-detecting sensor through simplified fabrication processes.
It is preferred that a plurality of ligh
Sakai Kazuhito
Sano Masashi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Lee John R.
Pyo Kevin
Rohm & Co., Ltd.
LandOfFree
Photoelectric tilt-detecting sensor and method of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photoelectric tilt-detecting sensor and method of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photoelectric tilt-detecting sensor and method of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2471483