Optical: systems and elements – Deflection using a moving element
Reexamination Certificate
2002-08-30
2004-09-28
Phan, James (Department: 2872)
Optical: systems and elements
Deflection using a moving element
C359S226200, C250S234000
Reexamination Certificate
active
06798548
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotational laser apparatus capable of forming a measuring reference plane, especially, a horizontal reference plane or any oblique setting plane inclined at a predetermined angle to the horizontal reference plane by means of laser beam.
2. Description of the Prior Art
Conventionally, there is known a rotational laser apparatus for forming a reference line on a laser plane measured with a laser-scanning plane by radiating laser beam from a laser beam source on a wall and so on while rotating the laser beam source. This is referred to as a laser survey machine. The laser plane is horizontally or obliquely formed and then high and low positions of or vertical positions of a point to be measured are determined based on the laser plane as reference.
When hoping to set the laser beam in a predetermined position, for example, an oblique position, data of changing an angler of gradient are input directly from input means into a main body or is set by moving a target which is provided in an radiating position.
Comparing with the direct input by the input means, setting by the target is easy and is relatively mostly used.
FIG. 1
shows a state of changing an angle of gradient at a conventional target
80
. Reflecting sections
85
a
and
85
b
are composed of mere reflection layers and reflecting sections
84
a
and
84
b
are composed of polarized light planes (&lgr;/4 birefringment members) in addition to the reflection layers. Laser beam is scanned on the reflecting sections to detect a measured position on the reflecting sections and is moved along the reflecting sections by a predetermined distance until the measured position is detected and then is stopped when the measured position is detected.
The laser beam moves to trace a laser plane and changes an angle of gradient thereof when the target is moved.
FIG. 2
shows a signal obtained when the laser beam is scanned on the target.
Basically, the measured point is determined by detection of the reflecting sections
84
a
and
85
b
. The reflecting sections
84
b
and
85
a
determine clearly rising portions of the signal. The laser beam of circularly polarized light is used to distinguish laser light reflected on a reflected plane. For example, if the target is scanned to obtain time t
1
from rise to decay and time t
2
from decay to rise and the t
1
is not equal to the t
2
, the laser beam is moved to become t
1
=t
2
.
FIG. 3
shows an optical and electrical construction of the rotational laser apparatus. A rotational radiating apparatus
1
comprises a light emitting part
3
, a rotated part
2
, a reflected-light detecting part
4
and a control part (CPU)
60
.
First, the light emitting part
3
will be explained.
A collimator lens
66
, a first &lgr;/4 birefringment member
67
and an holed mirror
68
are arranged in turn from a laser diode
65
side on an optical axis of the laser diode
65
which exits polarized radiating flux of linearly polarized light. The polarized radiating flux of linearly polarized light exited from the laser diode
65
is adapted to parallel by the collimator lens
66
and is changed into circularly polarized light by the first &lgr;/4 multiple refracting member
67
. The polarized radiating flux of circularly polarized light is exited through the holed mirror
68
into the rotated part
2
.
The rotated part
2
changes an optical axis of polarized light radiating flux
100
from the light emitting part
3
by 90 degrees and scans the changed flux. A penta-prism
18
of changing the optical axis of the polarized light radiating flux from the light emitting part
3
is provided in a mirror holder
13
to rotate about the optical axis of the polarized light radiating flux. The mirror holder
13
is connected through a scanning gear
17
and a drive gear
16
with a scanning motor
15
.
The radiated laser beam from the rotated part
2
is reflected on the target
80
and then polarized light reflected flux from the target
80
is inputted into the rotated part
2
. The polarized light reflected flux inputted in the penta-prism
18
is deflected toward the holed mirror
68
which causes the polarized light reflected flux to be incident into the reflected-light detecting part
4
.
Next, the reflected-light detecting part
4
will be explained.
A condenser lens
70
, a second &lgr;/4 birefringment member
71
, a pinhole
72
, a polarized light beam splitter
73
and a first photo-electric transformer
74
are arranged in turn from the holed mirror
68
side on a reflected optical axis of the holed mirror
68
. A second photo-electric transformer
75
is disposed on a reflected optical axis of the polarized light beam splitter
73
. An output from the first and second photo-electric transformers
74
and
75
is inputted in a reflected-light detecting circuit
76
.
The beam splitter
73
divides the polarized light reflected flux inputted in the reflected-light detecting part
4
and causes them to input into the first and second photo-electric transformers
74
and
75
. In this case, the second &lgr;/4 birefringment member
71
and beam splitter
73
are arranged so that the polarized light radiating flux exited from the light emitting part
3
passes through the &lgr;/4 birefringment member of the reflected plane of the target twice and flux of coinciding with deflected direction of the polarized light reflected flux which has been returned to the main body is inputted into the first photo-electric transformer
74
and the polarized light reflected flux which has been returned to the main body with the same deflected direction as a direction of the polarized light radiating flux exited from the light emitting part
3
is inputted into the second photo-electric transformer
75
.
Further, the control part
60
(CPU) will be explained.
A signal from the reflected-light detecting part
4
is inputted into the control part
60
. The control part
60
detects as a scanning signal the polarized light radiating flux scans which position of the target
80
from a relationship between the polarized light changing reflected part and a width of a reflected layer in the target
80
. A signal from the control part
60
based on the detected position controls an oblique control portion
62
so that the oblique mechanism is driven to oblique the rotated part
2
.
However, to detect the position on the target, further an oblique position for getting primarily and to position it, a high detecting ability and a calculating circuit of setting automatically the detection and position are required.
A high accurate light receiving detector and a complex optical system in which resolving ability is high to separate different polarized light fluxes are required for the high detecting ability. A high accurate workability together with a complex structure is, also, required for the complex optical system. The complex and high accurate structure is expensive and easily to damage.
High cost parts must be used to the control part for feeding back immediately detected results to a mechanical part.
Therefore, the rotational laser apparatus capable of performing an oblique setting automatically is expensive necessarily.
SUMMARY OF THE INVENTION
The present invention is made in view of the above and an object thereof is to provide a rotational laser apparatus capable of performing an oblique setting without requiring a complex optical system, such as a high accurate light receiver, to separate different polarized fluxes.
The rotational laser apparatus according to the present invention comprises a light emitting part for emitting scanning laser beam toward a target having reflected planes, a rotated part for forming a reference plane with the scanning laser beam from the light emitting part, an oblique mechanism for causing the rotated part to oblique, a light receiving part for receiving light reflected on the target and a control part for controlling the oblique mechanism according to a light receiving signal of the light receiving part.
Hayase Shin-ichi
Ohoka Mitsutoshi
Yamazaki Takaaki
Yoshino Ken-ichiro
Kabushiki Kaisha TOPCON
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Phan James
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