Variable curved surface projection screen - has flexible membrane curved by gas pressure to maintain symmetry at different radii of curvature

摘要

A projection screen includes a frame supporting the screen which is curved in both horizontal and vertical directions. The front side is covered by a membrane with an edging and the gear side with a cover attached to the edging of the front membrane to form a chamber within which the screen is contained. The chamber can be partially evacuated by a fan as a result of which the membrane assumes a concave shape with a relatively constant radius of curvature about a single point; the projection surface becoming spherical in section. The radius of curvature can be varied by a slide which controls the exhausting of the chamber.