Precision screen elevating and control means for a projection television receiver

摘要

An ultra-compact projection television receiver is disclosed comprising in combination cabinet means for enclosing the receiver components including a vertically reciprocable, rear projection viewing screen selectively storable in the cabinet. Precision elevating means provides for raising and lowering the screen between a stored position in the cabinet and a receiver-operable viewing wherein the screen is emerged. A television system has an ON control mode for providing television sound and pictures and an OFF control mode. Control means coupled to the elevating means and the television system provide for sensing the position of the screen in its reciprocation, and obstructions to said reciprocation manifested by increased resistance to said reciprocation, and correlatively controlling the elevating means and the OFF/ON control modes of the television system in response thereto. The control means are programmed to cause the screen to rise smoothly to its raised position without an abrupt stop and pictures to appear and sound to be heard the instant the raised position is attained. Safety is enhanced as obstructions to screen reciprocation are sensed and the reciprocation is stopped. The receiver is caused to automatically place the television system in the OFF mode when the screen is stored.