| 摘要 |
A video disc (11) is made by using the heat of a modulated focussed laser beam (13) as in prior proposals, but in order to get a more accurate record track, the medium on which the video disc record is made includes nitro-cellulose, or some other explosive material which is heated to its autoignition point when the heat in the focussed laser beam is above the critical level at which a pit is to be formed in the surface of the record. |
