A rewritable recording/display apparatus using a rewritable recording medium in which color development reaction occurs by thermal energy at a predetermined temperature, and in which a color extinguishing reaction occurs by thermal energy at a temperature lower than the color development temperature,...http://www.google.com.au/patents/US5231505?utm_source=gb-gplus-sharePatent US5231505 - Rewritable recording display apparatus and method of erasing record
