Device for optical recording and read-out of data along a prerecorded track

Abstract From the Canadian patent

The invention relates to optical devices enabling writing and reading of data on a disc comprising a preformed pattern, the recording and reading operations utilising a lighting spot able to illuminate only a single track element at a time. The invention provides a preformed pattern such that the spot overlaps on the track elements bordering a track interstice and vice versa, in such manner as to obtain a preformed contrast which can be accentuated by recording the data. The invention is applicable in particular to the recording of video frequency signals and to storing digital data on a disc.