| 摘要 |
The invention relates to modification of a laser beam produced,for purposes of aiming at a target, by instruments for measuring,controlling and treatment, such as pyrometers. It is known to provide such instruments with a single laser beam for aiming purposes. It is also known to provide such instruments with a plurality of divergent beams serving to define an area of a target. In a first embodiment the present invention provides a carrier having a beam splitter movable out of and into the path of the laser beam so as to provide respectively a single aiming beam and a plurality of fractional beams for defining an area of a target. In a preferred form, provision is made for periodical and repeated movement of the beam sputter into and out of the path of the aiming laser beam. In another embodiment, provision is made to increase the power of the single aiming beam at the tim e of splitting it into fractional beams; conversely where a relatively high power is applied t o the laser beam whilst it is split to provide fractional beams, provision is made to reduce the power of the laser at such times as it has reverted to a single laser beam, or again to pass the single laser beam through an attenuator. A further feature is the provision of movement o f the beam splitter into and out of the path of theaiming laser beam at a rate high enough to ensure persistence of vision, say at least twelve times per second. A further featu re of the invention is the construction of the beam-splitter carrier and of the instrument so as to be readily engageable onto and disengageable from each other, as for example by screw- threading, push-fit, snap-action or other readily releasable mechanical structure. The invention further provides methods, for aiming of such an instrument at a target by use of a single beam, and splitting the aiming beam into fractional beams for defining a selected area of the target, and particularly as an automatically repeated action, the fractional beams being directed, for example, to indicate points on the target bounding a selected area thereof; or again being directed at successive shifted points bounding the selected area of the target, or yet again with the fractional beams being merged to define a closed loop area of the target .
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