Yoshinori HONGUH

R & D Center, Toshiba Corp., 1, Komukai Toshiba-cho, Saiwai-ku, Kawasaki, 210 Japan

(Received June 1, 1994; Accepted August 15, 1994)

A noise power spectrum estimation method is presented for optical disk readout signal influenced by dust on the substrate. The noise due to dust has been modeled using geometrical optics and assuming the Poisson distribution for the dust particles. The noise power spectrum consists of two components: one comes from the effect of individual dust particles passing across the light beam, and the other comes from the effect of overlapping area of a particle and the inverted image of another particle. The feasibility of a thin-substrate optical disk was studied using this model. Dust will not have a serious effect on the readout signal when a 0.6 mm-thick substrate is used in place of the conventional 1.2 mm-thick substrate.

Key words : optical storage, optical disk, noise, dust, readout signal