We have designed optical structure to be used as tiles on the outsides of buildings for indoor illumination. To cover an
entire building, we have designed optical units to be used together that can compress light. The important factor in our
design is producing parallel exit beam from our single units. We have used saw-toothed surface with two different principles, the Co-focus and Parallel-plate, to design optical units. Finally, we analyze the efficiency and the beam divergence angle to compare these optical structures.
The utilization of sunlight is very helpful to saving resources. Different approaches were used for that purpose, but the
most of these systems only collect the light of some area of building and illuminate the room near window. Therefore, the primary idea of this paper is to collect large area of sunlight and convert planer light to parallel linear light so it could be guided to the deeper room. A "small unit" which could condense light is designed, and after combining, they could convert the planer light into the parallel linear light beam for the deeper room. Besides, we develop a mathematical model to describe the parallelism of the output light of the unit. OSLO is used to verify the model of the unit, and TracePro is used to verify the efficiency of the system.