1.  Field of the Invention
The present invention relates to a thermal recording method employing a recording member which can be adapted for use in a display or recording device.  The recording member is capable of reversible information recording and erasure by heating and cooling and allows optical information reading. 
2.  Related Background Art
There has long been known recording of information, such as image, with a material which undergoes a state change within a short period when brought above a certain temperature by thermal energy. 
In such conventional recording methods, there are known reversibly erasable and repeatedly usable recording materials such as photochromic materials, thermochromic materials or magnetic recording materials.  Thermochromy is found in various organic and inorganic substances, but fixing the recorded information is difficult in the case of photochromy.  Recently there have been proposed, as new thermal recording methods, a chalcogenide glass system utilizing crystalline-amorphous phase change and a system of a low-molecular fatty acid, an amide ester thereof or an ammonium salt thereof dissolved in a thermoplastic polymer and utilizing a thermal change in material (Japanese patent application Laid-open No.  117140/1982).  However the system of chalcogenide glass is expensive because th recording layer is prepared by evaporation and is also associated with the problem of toxicity.  Also a film in which a low-molecular material is dissolved in a thermoplastic polymer as disclosed in the Japanese patent application Laid-open No.  116380/1982 has not been used in practice since the recording and erasure have to be conducted in a delicate (i.e., precise) temperature range.