| 摘要 |
PURPOSE: To reduce an ineffective area in the peripheral part of a reflecting mirror by determining a fundamental surface of the reflecting surface based on an outer frame prescribing the front shape on the reflecting surface and a spline curve obtained from a plurality of required parabola groups, and assigning a rotating paraboloid. CONSTITUTION: When a fundamental surface of the reflecting surface is formed on the basis of a rectangular frame 1 prescribing the front shape of a reflecting mirror and a spline curve connecting parabola vertexes V-1 , V-2 ... with a composite curve 4 of a multiplex reflecting line every step width ΔY of reference parabolas Par-1 , Par-2 ..., a fat part is not formed in the periphery of the reflecting surface. When a crossing line group between the fundamental surface and a rotating paraboloid is determined and the rotating paraboloid is partially assigned in the adjacent crossing line groups, a reflecting step is formed along crossing lines positioned in upper and lower, right and left parts of the frame 1, and a reflecting mirror of a vehicle lighting appliance in which an ineffective reflecting area in a circumferential wall is reduced is obtained. |
