| 摘要 |
<p>The invention relates to systems for playing information stored in optical form (optical disks). According to the invention, use is made of the fact that the light from the source of illumination (L) of the optical disk (D) is a coherent source, in order to form a hologram on a photodetector array (BCCD). This hologram is the compounding of the unmodulated incident beam from the source with the beam reflected by the disk, modulated by the information to be played. Signal processing by Fourier transformation, shifting in the plane of spatial frequencies, inverse Fourier transformation, makes it possible to get back to the information written on the disk. The detection of the information can be much more thorough than in the case of the conventional playing of optical disks, since it involves not only the global modulation of light energy from the laser beam, but also phase modulation. This makes it possible to increase the information storage density, to reduce the precision of the optical and mechanical systems of the player, and to process electronic signals in order to correct defects in optical systems and focusing defects. <IMAGE></p> |
