| 摘要 |
PURPOSE: A horizontal/vertical reference beam generator is provided to prevent gap changes between a casing and a housing of a focusing lens unit as well as to fix a beam generator firmly. CONSTITUTION: A beam generating unit(10) consists of a beam generator(11) and a nut(12) for fixing the beam generator. A through hole is formed in the center of the nut to accept plural terminal pins(11C) of the beam generator, and a threaded part is formed outside. The beam generator includes a head(11A) of a front end, a support holder(11B) having a larger diameter than one of the head, and the terminal pins(11C) electrically connected with the head. The head of the beam generator is inserted into the through hole via a first space portion(101) of a casing(100). The head is exposed to a second space portion(102) via the through hole. The support holder is fixed to a sill portion(104) of the through hole to prevent the head from being inserted into the second space portion excessively. The nut is screwed into the first space portion of the casing. In a process of connecting the nut, the terminal pins are exposed to outside via the through hole. The front end surface of the nut presses the rear side of the support holder contacted with the sill portion. Thereby, the beam generator is inhibited from horizontal moving by the sill portion of the through hole. The beam generator does not move horizontally when external shock is applied to the nut.
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