Geometrical instruments – Straight-line light ray type – Level
Reexamination Certificate
2002-03-13
2004-01-13
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Straight-line light ray type
Level
C033S291000, C356S249000, C250S559300, C250S559400
Reexamination Certificate
active
06675489
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a laser sighting device for projecting a laser beam in a horizontal or in a vertical direction and forming a laser irradiation reference plane or for projecting a light beam to form a reference point.
As a conventional type laser sighting device, a device is known, which irradiates a laser beam compensated for vertical irradiation via a rotating pentagonal prism and forms a horizontal laser irradiation reference plane. Also, a device is known, which is tilted at an angle of 90° and irradiates a laser beam similarly via a rotating pentagonal prism and forms a vertical laser irradiation reference plane.
Also, a laser sighting device is known, which irradiates a laser beam in one direction or in a plurality of directions and forms one reference point or a plurality of reference points.
The laser sighting device for forming the laser irradiation reference plane or the laser sighting device for forming the reference point as described above may be designed as an independent laser sighting device respectively, while these may be integrated together from economical reason. That is, a part of the optical system is designed as replaceable or the entire optical system may be designed as replaceable as a unit so that the optical systems can be used respectively depending on each purpose of use, and formation of the laser irradiation reference plane and formation of the reference point can be achieved by the use of a single laser sighting device.
In the laser sighting device, for the purpose of forming a reference plane or a reference point accurately, the irradiating direction of the laser beam must be accurately compensated in a vertical or horizontal direction.
In the laser sighting device, which can form the laser irradiation reference plane and the reference point, a tilt sensor comprising a bubble tube is provided to perform leveling operation of the laser sighting device itself so that the laser beam can be irradiated in the vertical or horizontal direction.
However, in the conventional type laser sighting device, in which the optical system can be replaced, the rotary prism can be removed or inserted, or the entire optical system can be replaced depending on the intended purpose. However, there has been provided no means for performing positioning of the optical system and laser sighting device main unit, i.e., there has been provided no means for detecting the relationship between an optical axis of the optical system and the reference angle of the tilt sensor. For this reason, the optical axis of the optical system is deviated with respect to the reference angle of the tilt sensor and the laser irradiation plane or the laser irradiation line is often extremely deviated from the vertical direction or the horizontal direction.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a laser sighting device, which comprises means for detecting positional relationship between the optical system and the laser sighting device, and by which it is possible to maintain high accuracy in vertical and horizontal directions even when an emitting mode of the laser beam is changed depending on the intended purpose.
To attain the above object, the laser sighting device according to the present invention comprises a tilt detecting device having a liquid member for forming a free liquid surface and a fixed reflection member fixedly mounted, the tilt detecting device being used for detecting angular deviation between the free liquid surface and the fixed reflection member, a main unit for accommodating the tilt detecting device, and a laser beam irradiation unit removably mounted on the main unit. Also, the present invention provides the laser sighting device as described above, wherein there is provided a display unit for displaying a tilt angle and or displaying of an alarm based on a result of tilt detection by the tilt detection device. Further, the present invention provides the laser sighting device as described above, wherein there is provided a leveling unit for performing leveling operation based on a result of tilt detection by the tilt detecting device. Also, the present invention provides the laser sighting device as described above, wherein there are provided a coarse leveling unit for leveling of the main unit and a fine leveling unit for leveling the laser beam irradiation unit independently from the main unit. Further, the present invention provides the laser sighting device as described above, wherein the fixed reflection member is provided on the laser beam irradiation unit. Also, the present invention provides a laser sighting device as describe above, wherein the tilt detecting device comprises a photodetection element, a free liquid light projecting system for projecting a light beam toward the liquid member, a fixed reflection member light projecting system for projecting a light beam to the fixed reflection member, a photodetection optical system for guiding a reflection light beam from the free liquid surface of the liquid member and a reflection light from the fixed reflection member toward a photodetection element, and an arithmetic processing unit for calculating tilting of the main unit from deviation of two reflection images received by the photodetection element. Further, the present invention provides the laser sighting device as described above, wherein a first pattern is provided in the free liquid surface light projecting system, a second pattern is provided in the fixed reflection member light projecting system, and the reflection images are pattern images. Also, the present invention provides the laser sighting device as described above, wherein the first pattern and the second pattern are darkfield patterns. Further, the present invention provides the laser sighting device as described above, wherein the free liquid surface light projecting system and the fixed reflection member light projecting system project linearly polarized light of the same phase, wherein a &lgr;/4 phase contrast plate is provided in a common optical path for incidence and reflection of the light to and from the liquid member, wherein a &lgr;/4 phase contrast plate is provided in a common optical path for incidence and reflection of the light to and from the fixed reflection member, and wherein the photodetection optical system comprises a polarization optical member for transmitting only the reflection light from the liquid member and the fixed reflection member. Also, the present invention provides the laser sighting device as described above, wherein direction of polarization of the projected light beam is determined by a polarizing plate. Further, the present invention provides the laser sighting device as described above, wherein the laser beam irradiation unit comprises a laser light source for emitting a laser beam and the laser beam is irradiated by rotary irradiation. Also, the present invention provides the laser sighting device as described above, wherein the laser beam irradiation unit forms at least one spot light beam. Further, the present invention provides the laser sighting device as described above, wherein the laser beam irradiation unit comprises a laser beam splitting means, the laser beam splitting means is a rhombic prism with a right-angle prism on one end thereof, and the one end splits the laser beam to a transmission light and to a reflection light. Also, the present invention provides the laser sighting device as described above, wherein the laser beam irradiation unit irradiates the laser beam through a cylinder lens. Further, the present invention provides the laser sighting device as described above, wherein the laser beam irradiation unit irradiates the laser beam through a cylindrical lens. Also, the present invention provides the laser sighting device as described above, wherein a cross-sectional direction of the incident laser beam entering the cylindrical lens can be changed, and a spreading angle of a fan-shaped laser beam can be changed. Further, the present invention pr
Kodaira Jun-ichi
Ohtomo Fumio
Cohen Amy R.
Gutierrez Diego
Kabushiki Kaisha TOPCON
Nields & Lemack
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