Method of forming a reflection surface of a reflection mirror of a vehicle lamp

TLDR: In this paper, a basic reflection surface is formed by preliminarily setting a basic surface on which multiple paraboloids are to be formed, under a setting condition, and if the result of the preliminary setting is good, the setting condition is changed to another or other setting conditions, and the step of preliminary setting and evaluation of the incident angle distribution are repeated under the changed setting condition or conditions.

Abstract: A method of forming a reflection surface of a reflection mirror of a vehicle lamp includes the following steps. A basic reflection surface is formed by preliminarily setting a basic reflection surface on which multiple paraboloids are to be formed, under a setting condition. Angles θ at which light that is emitted from a light source located at a focal point is incident on different positions on the basic reflection surface, are calculated, to thereby form a plural number of contours of equal incident angles on the basic reflection surface. A distribution of incident angles is evaluated on the basis of the contours of equal incident angles. If the result of the evaluation is good, the basic reflection surface is set as a final basic reflection surface. If it is no good, the setting condition is changed to another or other setting conditions, and the step of the preliminary setting and the step of the evaluation of the incident angle distribution are repeated under the changed setting condition or conditions. Through those steps, a basic reflection surface can reliably be set which has an incident angle distribution excellent in suppressing the generation of dark portions on the reflection surface to the minimum and at the same time securing a required solid angle of the reflection mirror.