To realize the effective utilization of illuminating light by reducing the wasted illuminating light by optimally setting the projection range of the illuminating light projected to a body to be illuminated in accordance with the breadth and length size of the body to be illuminated. 被照明体に投射される照明光の投射範囲の設定を、その被照明体の横と縦とのサイズに応じて最適の設定を行い、無駄になる照明光を少なくして照明光の有効利用を図ることである。 - 特許庁