OPTICAL DATA RECORDING MEDIA AND METHODS FOR RECORDING AND READING DATA THEREON

摘要

An optical data recording medium (100) includes a substrate (220) and a markable coating (230) established on the substrate (220). The coating (230) includes an absorber (239) and a contrast agent (240). The absorber (239) is configured to absorb light of a first wavelength, and the contrast agent (240) is configured to undergo a chemical or physical change upon receiving energy from the absorber (239), thereby producing an optically detectable mark (242). The optically detectable mark (242) generates at least one of 1 ) a pattern that is readable with light of a second wavelength that is at least 200 nm apart from the first wavelength or 2) a pattern that is readable with light of the first wavelength.