Projection screen reflectance control for high contrast display using photochromic compounds and UV LEDs

This paper presents the first proof-of-concept implementation and the principle that realizes a projection display whose contrast does not decrease even with existing inter-reflection of projection light or environmental light. We propose the use of photochromic compounds (PhC) to control reflectance of a projection surface. PhC changes color chemically when exposed to UV light. A PhC is applied to a surface to control its reflectance by radiating UV light from a UV-LED array. An image is projected from a visible projector onto the surface to boost the contrast. The proof-of-concept experiment shows that the prototype system achieves approximately three times higher contrast than a projection-only system under natural light.