Patent ID: 7122779
Filing Date: 2006-10-17
Classification: G01C

Abstract:
1. A laser line beam emitting apparatus comprising: a laser beam emitter for emitting a laser beam there from, the laser beam emitter having an optical broad element through which the emitted laser beam flux are vertically or horizontally broadened so that a vertical or horizontal straight line is formed and drawn on its objects, the broadened laser beam flux having a central optical axis, a main covering for surrounding and covering said laser beam emitter therewith, the main covering comprising a plurality of faces and having at least one long length outlet formed on said faces which the vertically or horizontally broadened laser beam flux reach, and a plurality of dust protective coverings consecutively provided in said outlet of the main covering for preventing entry of dust thereinto while allowing the passage therethrough of the broadened laser beam flux, the broadened laser beam flux being in part reflected from the interior of said dust protective covering to form a reflective laser beam, one of the dust protective coverings being arranged in a position through which said central optical axis of the broadened laser beam flux passes, the dust protective covering at the passage of the central optical axis of the broadened laser beam flux having an interior curvature such that all of the reflected laser beam is reflected into the interior of the apparatus, and the reflected laser beam does not pass through said dust protective covering.