| 摘要 |
PURPOSE:To vary the beam diameter of a projection light beam optionally and to facilitate optical-axis adjusting operation, etc., by arranging two cylindrical lenses in front of a light emitting element so that their optical axes are aligned with the optical axis of the light emitting element, and allowing one cylindrical lens to rotate on its optical axis. CONSTITUTION:A semiconductor laser 12 as the light emitting element is arranged in the case 11 of a projector 10 and the two plane cylindrical lenses 1 and 2 are provided in front of the laser so that the optical axes are aligned; and the cylindrical lenses 1 and 2 are supported on the case 11 rotatably on their optical axes. Thus, the lens 2 is rotated, to the projection light beam of the projector 10 is deformed from a collimated beam to a diverged beam or vice versa and its diameter is varied optionally. Consequently, the beam diameter of the projection light beam is increased to perform positioning and then the beam diameter is reduced gradually to make a highly accurate adjustment, thereby facilitating the operation.
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