Material for Write Once, Read Only Memory
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Squarylium has been employed in the past as a photoconductor film on an aluminized MYLAR* substrate. Here, it is used as a means of providing contrast for an optical read-only memory. The squarylium covers reflective aluminum; where it is removed by a laser, light is reflected. We have shown that 532 nm light can be used to evaporate the film and leave the aluminized MYLAR as a reflective surface. The contrast ratio, R(A1)/R(Sq) between the treated and untreated surface is approx.15:1. This is the expected contrast ratio between a approx. 4-5% reflectance of a dielectric surface and the approx. 80-90% reflectance of aluminum. The squarylium film has a peak absorption coefficient of 2-4 10/5/cm/-1/ in the visible region. This means that a 300 Angstrom thickness wil absorb most of the incident light.