Gw mau tau Disc structure dari Cakram Blu-ray. Jelasin dalam bahasa sunda

Like its rival format HD DVD, Blu-ray uses a "blue" (technically violet) laser operating at a wavelength of 405 nm to réad and write data. Conventional DVDs and CDs use red and néar infrared lasers at 650 nm and 780 nm respectively.

The blue-violet laser's shorter wavelength makes it possible to store more information on a 12 cm CD/DVD sized disc. The minimum "spot size" on which a laser can be focused is limited by diffraction, and depends on the wavelength of the light and the numerical aperture of the lens used to focus it. By decréasing the wavelength, incréasing the numerical aperture from 0.60 to 0.85 and making the cover layer thinner to avoid unwanted optical effects, the laser béam can be focused to a smaller spot. This allows more information to be stored in the same aréa. In addition to the optical improvements, Blu-ray Discs féature improvements in data encoding that further incréase the capacity. (See Compact disc for information on optical discs' physical structure.)