miscellaneous articles [6]

overhead projector

Device that projects the enlarged image of a document printed on a transparency on a screen located behind the user.

optical stage

Glass plate that is lit by an internal light; the document to be projected is placed on it.

optical lens

Transparent optical disk that captures the light from the optical stage and makes it converge toward the mirror.

projection head

Movable part that contains the lens and mirror; a focusing ring changes its position to give a clear image on the screen.

mirror

Polished glass surface that directs light from the lens toward the projection screen.