| 摘要 |
<p>The overhead projector can be used during lectures without darkening the room. The projection beam can be horizontal or up to a max. of 40 deg. from the horizontal. The projector can be equipped with a magazine for supplying slides and a receiver for collecting them again after projection. A lamp (11) with condenser lenses (14) and aspherical lens (12) supplies illumination via a mirror (15) for projecting the transparency (5) through an objective lens (6) and onto a second beam diverting mirror (7). The latter are focussable (9, 17) and the transparency is protected from lamp heat by heat absorbing filters (13).</p> |
