Abstract: A piracy protection digital recording medium comprising a polymeric layer incorporating an optical state change material in conjunction with a cationic photoinitiator.

Abstract: A storage case of storing optical digital data storage media, the case including a cover with a defined area therein that permits transmission of certain energy to the medium stored therein while the area of the cover outside of the defined area does not.

Abstract: An optical media device comprises a mask layer placed over a data layer, and that includes chemical ingredients designed to render the data layer unreadable by an optical reader in a first initial state, and allow the data layer to be read when converted to a second state. The mask layer is optically opaque in the first state, and is optically transparent in the second state. The chemical ingredients include a dye that absorbs light in the visible light and/or optical reader spectrum, and a further chemical that is activatable to shift the dye's absorption wavelength so the data layer can be read by the optical reader. The activation source is radiative emission having a wavelength different from that of visible light and/or the optical reader. The activation source can be used at the point of sale of the device to render the device readable upon purchase.

Abstract: A photoemissive photocathode, being a metal with a low work function and preferably tantalum-surfaced cesium-antimonide, is illuminated with pulses of 5320 .ANG. laser light, typically 20 psec at a 20 Hz repetition rate, to emit electrons by the photoelectric effect. The emitted electrons are accumulated in a spatial region near the photocathode by a grid electrode. The same laser pulses activate a semiconductor switch, normally an LiTaO.sub.3 crystal doped with 2.24% Cu, to apply a high voltage, typically 100 Kv, between the photocathode and an anode. The accumulated electrons are accelerated, and focused, as an electron beam that strikes the anode, typically in a focal spot of less than 0.5 mm diameter. Time-resolved x-ray pulses, typically K band of 20 picoseconds duration with 4-10 microjoules energy each, are produced. A laser-induced pulsed wide-area table-top-size embodiment of the x-ray source reliably generates a 1-10 mW/cm.sup.2 flux of hard, 0.