Optical waveguides – With optical coupler – Input/output coupler
Patent
1996-10-18
1998-06-09
Lee, John D.
Optical waveguides
With optical coupler
Input/output coupler
385 31, 385 33, 385 39, G02B 634
Patent
active
057648280
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical apparatus and an apparatus capable of outputting a ringed light beam having a uniform distribution of light intensity and more particularly to an optical apparatus for controlling an angle of divergence of a ringed light beam which is capable of irradiating a narrow light beam (slit beam) whose distribution of light intensity is uniform in the direction of 360.degree. concurrently with any angle of divergence with respect to an optical axis.
BACKGROUND ART
Hitherto, as an optical apparatus for irradiating a slit beam in the direction of 360.degree., there has been known an apparatus which transforms a laser beam output from a laser source into a ringed beam by inputting it to and reflecting from or transmitting through a conical prism or the like having a conical light reflecting surface or a conical light transmitting surface.
Further, among levels used in construction and civil engineering works, there has been known one which scans a laser beam in the direction of 360.degree. by turning an optical element such as a prism for reflecting or transmitting the laser beam to change an irradiating direction thereof by means of a turning mechanism such as a motor.
However, the inventors et al. have clarified that it is extremely difficult to obtain a ringed beam having a uniform distribution of intensity in the direction of 360.degree. with the above-mentioned technology using the conical prism and the like just by transforming the beam output from a semiconductor laser or the like into the ringed beam via the conical prism or the like because the beam has an anisotropy that its distribution of sectional intensity is different in the vertical and horizontal directions. It has been also clarified that the prior art technology has had a problem that it is difficult to obtain a uniform slit beam due to a diffraction of light input to an apex portion of the conical prism or the like.
The technology of turning the prism or the like also has had a problem that because the irradiating direction of the laser beam is scanned, the laser beam cannot be received at two or more points in the same time and the precision of leveling carried out by means of the level by receiving the laser beam at a plurality of points cannot be so high. It has had also other problems that the measuring accuracy drops due to aged deterioration of the turning mechanism and that it requires a power source for supplying driving force to the motor or the like.
Accordingly, it is an object of the present invention to solve the aforementioned problems by providing an optical apparatus for controlling an angle of divergence of a ring beam which is capable of outputting the ring beam having a uniform distribution of light intensity.
SUMMARY OF THE INVENTION
An optical apparatus for controlling an angle of divergence of a ring beam of the present invention described in claim 1 comprises parallel beam generating means which is capable of outputting a parallel light beam; ring beam generating means to which the parallel beam output from the parallel beam generating means is input and which is capable of outputting the input light beam by transforming into a ringed light beam whose shape is annular or partly annular when it is irradiated to an imaginary plane vertical to an optical axis and which diverges with a predetermined angle of divergence with respect to the optical axis; and divergent angle changing means for changing the angle of divergence so that an expansion ratio or reduction ratio of the irradiated shape of the ring beam output from the ring beam generating means with respect to a distance from an output end face changes on the way.
By constructing as described above, the ring beam having a uniform distribution of intensity can be irradiated with an arbitrary angle of divergence with respect to the optical axis in accordance to its use.
That is, the present invention is characterized in that it contains expansion ratio changing means for changing the expansio
REFERENCES:
patent: 4834484 (1989-05-01), Gorman et al.
patent: 4961622 (1990-10-01), Gorman et al.
patent: 5113244 (1992-05-01), Curran
Iga Kenichi
Katsura Shinichi
Kawaguchi Yuzo
Kawaguchi Kogaku Sangyo
Lee John D.
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