Abstract: The interior of a mailbox is illuminated with a highly efficient LED lamp powered by a rechargeable battery. The LED lamp is turned on when the mailbox door is opened. A solar panel is mounted under a light-transmitting cover located on the roof of the mailbox for recharging the battery. The illumination system is for the most part composed of a pair of compact modular assemblies which are carried by the mailbox.

Abstract: An immersed non-polarizing beamsplitter includes thin film groups and one or more additional thin films. Each of the thin film groups by itself fails to provide a non-polarizing reflection, but the combination of the thin film groups and the additional thin films provides a non-polarizing reflection. Each thin film group can consist of four layers, one of a higher refractive index material, two of an intermediate refractive index material, and one of a lower refractive index material, and at least one of the additional thin films is made of a material not used in the thin film groups. The additional thin films can precede, be between, or follow the thin film groups along the path of light through the beamsplitter. The order of the thin films in the groups can all be the same or can vary to improve performance of the non-polarizing beamsplitter.