Apparatus for reading a disc-shaped record carrier with video luminance and chrominance information
Device for the optical read-out of a diffractive track belonging to a data carrier in the form of a disc or tape
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ApplicationNo. 05/726161 filed on 09/24/1976
US Classes:369/44.24, Means to mask or shield a portion of the beam250/201.5, With optical storage medium; e.g., optical disc, etc.250/202, Following a pattern (e.g., line or edge)250/570, Tape, drum, or disc types369/112.24, Plural distinct lenses369/117, Having movable shutter or light gate369/121, With particular light source (e.g., laser, CRT with phosphor)369/44.41Arithmetic operation using plural photodetectors
ExaminersPrimary: Cardillo, Raymond F. Jr.
Attorney, Agent or Firm
Foreign Application Priority Data1975-09-29 FR
AbstractThe invention relates to the optical reading of a support comprising a track along which is arranged a series of information items which optically translate a carrier wave angularly modulated by the information. The read-out system uses a single lens for projecting a quasi-punctiform spot onto the support; a photodetector comprising four cells arranged in a square and asymmetrical illumination of the lens to ensure detection of the information and simultaneous supply of defocussing and tracking deviation signals.