| 摘要 |
<p>An aid for positioning a user's head with respect to a remote object is described. The device comprises a visor (10), having front (14) and back (13) edges, the visor (10) being attached at its back edge (13) to a headpiece (17). A pair of spaced line markings (15) are provided on the underside (12) of the visor (10), the markings (15) being located substantially equidistant from an axis (16) extending between the front (14) and back (13) edges and bisecting the visor (10). The distance (d) between the markings (15) closest to the back edge (13) of the visor (10) substantially corresponds to the distance between the eyes of the user.</p> |
