Utilization of Nonconvex Shapes as Horizontal Section of Paper Folding Lampshade Constructed with Skew Quadrilateral Elastic Folding

Abstract

Lampshades were developed as wind shield for light source when fire was used for light source. Though contemporary light sources, like LED lamp, fluorescent lamp and incandescent light, are working with electricity and wind shield is not required for light source, almost all light sources are still covered by lampshade to arrange or control luminous flux from light source. And combination of lampshades and light sources may give distinctive impression to surrounding people. Until now, paper folding method ‘SQEF’ (Skew Quadrilateral Elastic Folding) was proposed to construct shapes with non-flat texture in the field of lampshade design. With SQEF methods, final shape is constructed by skew quadrilateral unit with a curved surface. As each skew quadrilateral unit is composed by continuously curved surface, luminance distribution within each unit is continuous as well. The shapes of section appeared in proposed lampshades are convex and curved surface in each unit is concave. The purpose of the research described in this paper is expansion of the horizontal sections of lampshades to nonconvex shape to generate convex unit. The buffer part was inserted between concave parts to combine them. An example of the lampshade including concave parts was manufactured. And finally, luminance distribution on the lampshade was examined.