Patent ID: 6839316
Filing Date: 2005-01-04
Classification: G11B,Y10T

Abstract:
1. An optically-readable medium comprising: a reflective layer; at least one substrate coupled to said reflective layer, said substrate layer comprises one or more substrate layers through which laser light from an optically readable medium reading device passes before impinging on the reflective layer; a first reactive agent disposed in the optical path of said laser light, said first reactive agent inhibits the ability of the laser light to read the reflective layer after a first predetermined time; a second reactive agent, said second reactive agent degrades the integrity of the reflective layer after a second predetermined time; and wherein said first reactive agent inhibits the ability of the laser light to read the reflective layer by changing from a first optical state that is substantially transparent to the laser light to a second optical state that is substantially opaque to the laser light in response to a predetermined stimulus within said first predetermined time.