University of Tsukuba Assigned Patent

University of Tsukuba, Tsukuba-shi, Japan, has been assigned a patent (9,029,068) developed by Hase, Muneaki, Makino, Kotaro, and Tominaga, Junji, Tsukuba, Japan, for a “phase change device having phase change recording film, and phase change switching method for phase change recording film.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”Allowing the rate of phase change to be controlled at the time period of phonons, (approx. 270 fs) for the purpose of achieving a substantially higher recording-erasing speed compared to what can be achieved with conventional technologies relating to optical recording media using phase change. A femtosecond pulse laser is shaped into pulse trains each having a first pulse and a second pulse using a Michelson interferometer, and the time interval of first and second pulses is matched with the time period of lattice vibration of a material constituting the phase change recording film to be irradiated, thereby inducing phase change.“

The patent application was filed on August 9, 2010 (13/503,346).