Transparency projector with additional lens system for projection of cursor

摘要

Transparencies (DIA) are projected by a projector having a light source (L1) and objective (OBJ), with an additional lens system (LS) which produces a virtual image of an LCD display (LCD1) in the plane of the transparency, so that the transparency and one or several arrows etc. or cursors are shown together on the projection wall or screen. The position of the cursor on the display can be varied by means of electronics and a control program. A trackball, joystick, or other means may be provided for moving the cursor position or a laser pointer may be used to transmit the co-ordinates of the cursor position to the control system.