| 摘要 |
A projection screen having spaced apart lateral edges and opposite upper and lower ends that is mounted at its upper end by appropriate support means to a wall and which has a means for releasably magnetically securing the lower end of the screen to the wall. By securing the lower end of the screen to the wall while the upper end of the screen is spaced apart from the wall, the keystone effect that occurs when an overhead projector is used to upwardly project an image onto a vertically hanging screen is eliminated.
|
