Optics: measuring and testing – Angle measuring or angular axial alignment – Photodetection of inclination from level or vertical
Reexamination Certificate
2001-10-25
2004-02-10
Buczinski, Stephen C. (Department: 3662)
Optics: measuring and testing
Angle measuring or angular axial alignment
Photodetection of inclination from level or vertical
C200S06145M, C200S061520, C250S231100, C073S335110
Reexamination Certificate
active
06690457
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical inclination sensor provided in various apparatuses such as electronic cameras and robots for detecting the inclination condition of the apparatuses.
2. Description of the Related Art
Conventional optical inclination sensors using a sphere are disclosed, for example, in Japanese Unexamined Patent Publication JP-A 11-14350 (1999).
FIG. 7
is a plan view showing the structure of a conventional optical inclination sensor
71
in a simplified form.
FIG. 8
is a cross-sectional view taken on the line VIII—VIII of FIG.
7
.
FIG. 9
is a cross-sectional view taken on the line IX—IX of FIG.
7
.
The conventional optical inclination sensor includes a light emitting section
73
including a single light emitting element
72
; a light receiving section
75
including a light receiving element
74
having two light receiving surfaces
74
a
and
74
b
that receive diffused light from the light emitting section
73
; a holder
78
holding the light emitting section
73
and the light receiving section
75
and having two inclined surfaces
76
and
77
forming a predetermined angle with each other; a lid
79
fitted to the holder
78
; and a sphere
80
serving as a detection object that moves freely on the two inclined surfaces
76
and
77
of the holder
78
. The conventional sphere
80
is made of iron and has a diameter of 1.0 to 1.2 mm, and a surface roughing treatment is performed on the surface of the sphere
80
.
In the conventional optical inclination sensor
71
, when the holder
78
is upright without inclined, the diffused light from the light emitting section
73
is received by the two light receiving surfaces
74
a
and
74
b
, and when the holder
78
is inclined rightward or leftward, the sphere
80
moves to the end of the inclined surface in the direction in which the holder
78
is inclined, so that the light is intercepted from one of the two light receiving surfaces
74
a
and
74
b
and is received by the other of the surfaces
74
a
and
74
b.
The conventional optical inclination sensor
71
faces the following problem. The holder
78
only has the two inclined surfaces
76
and
77
forming the predetermined angle with each other, and the surface of the lid
79
facing the sphere
80
is a plane. Therefore, when the holder
78
is upright without being inclined, the sphere
80
is situated midway between the two inclined surfaces
76
and
77
, and the two light receiving surfaces
74
a
and
74
b
both receive the diffused light from the light receiving surfaces
74
a
and
74
b
both receive the diffused light from the light emitting section
73
. When the holder
78
is inclined rightward or leftward, the sphere
80
moves to the end of one of the two inclined surfaces
76
and
77
, so that the diffused light from the light emitting section
73
is intercepted from one of the two light receiving surfaces
74
a
and
74
b
and is received by the other of the surfaces
74
a
and
74
b
. As described above, the optical inclination sensor
71
can detect only three conditions, namely an upright condition where the holder
78
is not inclined, a rightwardly inclined condition where the holder
78
is inclined leftward, and cannot detect a condition where the holder
78
is inverted.
Moreover, since the two light receiving surfaces
74
a
and
74
b
receive the diffused light from the light emitting section
73
when the holder
78
is in the upright condition, in the case where the optical inclination sensor
71
is provided in an apparatus frequently used in the upright condition, the light is incident on the light receiving section
75
, so that a condition where current flows through the light receiving section
75
continues for a long time. This increases power consumption.
Further, since the sphere
80
used for the conventional optical inclination sensor
71
is small in mass, when the optical inclination sensor
71
is inclined, there are cases where the sphere
80
stays in contact with the holder
78
and does not move due to static electricity. Therefore, in order for the sphere
80
to easily move when the optical inclination sensor
71
is inclined, although the cost of manufacturing increases, a surface roughing treatment is performed on the surface of the sphere
80
to reduce the area of contact of the sphere
80
with the holder
78
. However, the angle of inclination of the optical inclination sensor
71
at which the sphere
80
starts to move is not always the same but varies largely.
SUMMARY OF THE INVENTION
An object of the invention is to provide an optical inclination sensor capable of detecting four conditions, namely an upright condition, a rightwardly inclined condition, a leftwardly inclined condition and an inverted condition, and in which power consumption can be reduced and the variation in the angle of inclination at which the detection object starts to move is small.
The invention relates to an optical inclination sensor for detecting a condition of inclination of an object to horizontal, the optical inclination sensor comprising:
a light emitting section including a light emitting element;
a light receiving section including a light receiving element having two light receiving surfaces;
a movable detection object for adjusting a light receiving condition of the light receiving section by blocking or opening paths of light from the light emitting section to the light receiving section;
a holder for housing the light emitting section, the light receiving section and the detection object, the holder having an inner surface including surfaces parallel to, vertical to and inclined to horizontal when the holder is in an upright condition; and
a lid shaped to fit to the holder, the lid having an inner surface including surfaces parallel to and inclined to horizontal when the holder is in the upright condition and the lid is fitted thereto,
wherein the detection object is movably housed in a housing space defined by the holder and the lid, and the path of light and the movement path of the detection object are formed so that the following conditions are distinctively detectable according to a position along the movement path of the detection object in the housing space:
the upright condition of the holder;
a rightwardly inclined condition of the holder;
a leftwardly inclined condition of the holder; and
an inverted condition of the holder.
According to the invention, the optical inclination sensor can detect the inclination conditions, that is, the four conditions, namely the upright, the rightwardly inclined, the leftwardly inclined and the inverted conditions. Consequently, although in the conventional optical inclination sensor capable of detecting only three conditions, namely the upright, the rightwardly inclined and the leftwardly inclined conditions, to detect the four conditions, it is necessary to provide in the apparatus two sensors disposed so as to be relatively rotated 90 degrees from each other, in the optical inclination sensor capable of detecting the four conditions, it is necessary to provide only one sensor in the apparatus. This reduces the cost of manufacturing, and reduces the space in the apparatus necessary for mounting the sensor to reduce the size of the apparatus.
In the invention it is preferable that the path of light and the movement path of the detection object are formed so that when the holder is in the upright condition, paths of light from the light emitting section to the two light receiving surfaces are both blocked by the detection object,
when the holder is in the rightwardly or the leftwardly inclined condition, one of the paths of light from the light emitting section to the two light receiving surfaces is blocked by the detection object, and
when the holder is in the inverted condition, the paths of light from the light emitting section to the two light receiving surfaces are both opened.
According to the invention, since the paths of light from the light emitting section to the two light receiving
Buczinski Stephen C.
Sharp Kabushiki Kaisha
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