A beam splitter of natural light guiding system based on dichroic prism for ecological illumination

Abstract

In thremmatology, many researches focus on ecological illumination for improving the growing speed of animal or plant. According to the Trichromatic theory, any specific color can be made up of red, green, and blue light. Sunlight has full spectrum so it is the most applicable source. A Natural Light Guiding System includes collecting, transmitting, and lighting parts. In our research, we would like to design a beam splitter in the transmitting part to separate the sunlight into red, green, and blue light for ecological illumination. We use high pass and low pass dichroic coatings in a prism, called dichroic prism, to be the beam splitter to separate the wavelength. For measuring the spectra of the exit beams, we build a space with the Natural Light Guiding System. In the space, the spectra of sunlight outside and inside the space and the exit beams of the beam splitter are measured. Finally, we use prismatic structure to design the beam splitter, and optimize the surface of the element with aspheric surface and Fresnel surface to reduce the beam angle of exit light.