REFLECTION SURFACE DESIGN METHOD OF REFLECTION MIRROR OF VEHICLE LIGHTING FIXTURE

摘要

PROBLEM TO BE SOLVED: To provide a reflection surface design method of a reflection mirror of a vehicle lighting fixture in which controllability of a light distribution pattern and efficiency in designing are enhanced. SOLUTION: The refection surface design method of the reflection mirror used for the vehicle lighting fixture includes a first basic curve production step for producing a first basic curve Q; a second basic curve production step for producing a plurality of second basic curves R; and a surface shape production step for producing the surface shape of the reflection surface RS based on the first basic curve and a plurality of second basic curves. In the first base curve production step, after a partial curve Qi is produced, a step for producing a latter partial Qi+1 so as to link to the partial curve Qi is repeated. Thereby, the first base curve Q formed by linking a plurality of partial curves Qi is produced and the respective partial curves Qi are produced based on a corresponding shape parameter respectively.