Reflection-type projection screen
View Patent ↗A reflection-type projection screen is provided having uniformly high gain over a wide range of viewing angles. The projection screen includes a dual-purpose light reflective, supportive substrate including at least one unpigmented flash-spun plexifilamentary film-fibril sheet having a light reflectance of greater than about 85% and a gloss of less than about 10% when measured at a 60° incident angle, and an optical diffusion layer of a light transmissive melt-processible polymer containing diffusion-enhancing particles covering at least one surface of the substrate. The projection screen has an optical gain of between about 0.90 and about 2.0 and the optical gain deviates by no more than about 8% over viewing angles between −60° and +60°. The projection screen has good drapeability, rollability the ability to lay and hang flat. The projection screen can also be recycled.
1. A reflection-type projection screen comprising:
a) a dual-purpose light reflective, supportive substrate having a front surface and rear surface comprising at least one unpigmented flash-spun plexifilamentary film-fibril sheet having a thickness between about 5 mils and about 15 mils and having a light reflectance of greater than about 85% and a gloss of less than about 10% when measured at a 60° incident angle; and
b) an optical diffusion layer covering the front surface of the substrate having a thickness between about 0.2 mil and about 15 mils comprising a light transmissive melt-processible polymer containing diffusion-enhancing particles;
wherein the projection screen has an optical gain of between about 0.90 and about 2.0 and wherein the optical gain deviates by no more than about 8% over viewing angles between −60° and +60°.
2. The projection screen of claim 1 wherein the optical diffusion layer contains less than about 10% by weight of diffusion-enhancing particles based on the weight of the melt-processible polymer.
3. The projection screen of claim 1 wherein the substrate comprises a polymer selected from the group consisting of polyethylene, polypropylene, polyester, acetyl polyoxymethylene resin, polyamide.
4. The projection screen of claim 1 wherein the optical diffusion layer comprises a polymer selected from the group consisting of polyethylene polymers and blends, polypropylene polymers, copolymers of propylene and ethylene, ethylene copolymers, copolymers of ethylene and vinyl acetate, copolymers of ethylene and acrylate, blends of ethylene copolymers, blends of ethylene copolymers with E/MAME and E/MAME.
5. The projection screen of claim 1 wherein the diffusion-enhancing particles comprise a pigment selected from the group consisting of titanium dioxide and calcium carbonate.
6. The projection screen of claim 1 further comprising a backing layer covering the rear surface of the substrate comprising melt-processible polymer containing an opacifying agent.
7. The projection screen of claim 1 wherein the diffusion layer is formed on the surface of the substrate by casting, extrusion, thermal lamination or adhesive lamination.