In this work we have designed a novel optical architecture for LED-based LCOS projectors. First we have investigated the available LEDs and characterized them. Further the LED illumination engine with the custom collection system is designed, simulated and manufactured to use them in our novel architecture that is based on two LCOS light valves. This architecture is firstly simulated and optimized by using ray-tracing software ZEMAX. After testing the several parts of this architecture experimentally, we have built a LED projector demonstrator. The several aspects that is evolved to optimally and efficiently use the available light flux will be discussed.