| 摘要 |
PURPOSE:To make it possible to exactly adjust the quantity of the collimated beams of light or condensed light emitted from an optical member by coating the surface of the optical path part consisting of metal with phosphate, thereby preventing the light reflection of the optical path part of the optical member. CONSTITUTION:The surface of the optical path part consisting of metal is immersed into an aq. soln. contg. phosphoric acid ions and metal ions to coat the surface of the optical path part with the phosphate. For example, the surface of a lens barrel (optical path part) 1 made of iron is subjected to washing with trichloroethylene, degreasing treatment and washing with water as pretreatments. The lens barrel 1 is then immersed into a heated treating liquid in which Mn, Fe, H2PO4 and NO3 and are dissolved thereafter, the lens barrel is subjected to washing with water and washing without hot water then to drying. As a result, the film of the phosphate consisting mainly of manganese phosphate is formed on the surface of the lens barrel 1. Then, the light beams cast onto the inside surface of the lens barrel among the incident laser beams on the lends barrel 1 are nearly completely absorbed and are not reflected. All the exit light beans from the lens 3 are thus taken out as the collimated beams of light. |
