"beautifu" - 1 õppematerjal

Elektroonika Alused

So, a highly magnified section of track might look something like: Pits are formed in the polycarbonate disk by an injection molding process. As such, they represent some of the smallest mechanically fabricated objects made by humans. The width of a CD pit is approximately the wavelength of green light. The tracks are separated by approximately three times the wavelength of green ligh Diffraction from these features (so very close to the wavelength of light) is what gives CD disks their beautifu colors. A thin layer (50-100 nm) of metal (aluminum, gold or silver) covers the pits. An additional thin layer (10-30 microns) of polymer covers the metal. Finally, a label is silk-screened on the top. Notice that the pits are far closer to the silk screened side of the disk (20 microns) than they are to the read-side of the disk (1.55 mm). Thus, it is easier to permanently damage a disk by scratching the top -- than the bottom! C. Reading the pits The CD disk is actually read from the bottom