GB768394A - Improvements in and relating to apparatus for taking composite pictures by photography or television - Google Patents

Abstract

768,394. Television. ALEKAN, H. A. Jan. 3, 1955 [Jan. 7, 1954], No. 56/55. Class 40 (3). [Also in Group XX] In an installation for television transmission of a composite scene comprising illuminated objects and projected images a camera and an optical projector are situated on the same side of a projection screen and an optical reflector is disposed with respect to the camera and projector so that the virtual image of the objective of one coincides with the objective of the other, the screen being formed of transparent beads of a refractive index between 1.7 and 2.0 embedded in a reflecting layer. In the form shown in Fig. 3 a foreground subject 8 disposed in front of an auto collimating screen 5 is photographed by a camera 6. The background is projected by a projector 7 by reflection from a semi-transparent mirror 9. One form of auto collimating screen is shown in Fig. 2 and comprises a backing layer 1 supporting a reflecting layer 2 in which glass beads 3 are embedded and retained by a binder 4 for example of resin. The reflecting layer may itself be composed of separate layers of which the uppermost is rendered more reflecting by the addition of aluminium flakes. The binder is black, or covered with a black layer and may also contain aluminium flakes. The glass balls are of 0.05-1.5 mm. diameter preferably 0.10- 2.5 mm. and of a refractive index between 1.7 and 2.0, preferably between 1.8 and 1.9. The balls may have a low reflection coating.