Plane illumination device

Abstract

Abstract PURPOSE:To obtain uniform plane illumination with no intensity nonuniformity by distributing an opaque pattern at the same distribution density in the longitudinal direction of a light source and at the decreasing distribution density apart from the light source in the perpendicular direction so that the transmitted light quantity distribution is unified. CONSTITUTION:A light control plate 10 is made of a polyester film 11 deposited or printed with dot-shaped opaque aluminum pattern 12, for example, and the opaque pattern 12 has opaque distribution so that the light quantity emitted from the light control plate 10 is unified. Arrows MD and TD on the light control plate 10 indicate two directions for the two-axis extension when the polyester film 11 is manufactured, and they are perpendicular to each other. The thermal contraction coefficient of the polyester film 11 differs according to the extension direction, and the thermal contraction coefficient in the MD direction is larger than that in the TD direction. The direction TD with a smaller thermal contraction coefficient of the polyester film 11 is made to coincide with the direction perpendicular to the longitudinal direction of a light source 13. No intensity nonuniformity occurs at a high temperature which may cause thermal contraction.

Inventors

• 👤 Takashi Yamamoto
• 👤 高司 山本
• 👤 Hirobumi Iwamoto
• 👤 博文 岩本

Bibliographic Details