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Dynamic Reflectance Control for High Contrast Projection using Photochromism

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.

Principle of the proposed method: (a) when visible lights are projected on a uniform white screen, the contrast of the reflected light is identical to that of projected light; (b) when PhC is applied to the screen and the screen reflectance is modulated by UV radiation, the contrast of the reflected light is the multiplication of the reflectance and projected light.

Experimental setup: (a) overview, (b) side view of the screen and UV LED array, and (c) front view of the UV LED array when the screen is removed.

Experimental result: (a) target luminance map, (b) projection results under conventional condition, (c) projection results under proposed condition; (d), (e), and (f) are false color representations of (a), (b), and (c), respectively.

Publications

  • Daisuke Iwai, Shoichi Takeda, Naoto Hino, and Kosuke Sato, "Projection Screen Reflectance Control for High Contrast Display using Photochromic Compounds and UV LEDs," Optics Express, Vol. 22, No. 11, pp. 13492-13506, 2014. [open access]
  • Naoto Hino, Daisuke Iwai and Kosuke Sato, "Dynamic Reflectance Control of Photochromic Compounds for 3D High Dynamic Range Display," CVPR 2012 Workshop for Computational Cameras and Displays, 2012. (No publication)