HEATING SHEET OF MULTI-LAYERED STRUCTURE

摘要

PURPOSE: A heating sheet of multi-layered structure is provided to promote growth of plants by preventing release of harmful electromagnetic waves from heating layers. CONSTITUTION: A heating sheet has a structure of multi-layers. A heating layer(24) in the central portion is made of fabrics and includes electrodes(22) and semiconductor devices(26). Main coating layers(28,28') are formed in the both sides of the heating layers(24) to prevent the heating layer(24) from exposure. Surface layers(30,30') are formed on the upper and lower parts of the main coating layers(28,28') and include electromagnetic wave shielding means. The electromagnetic wave shielding means are made of hardwood charcoal. Side coating layers(34,34') are provided at both ends of the heating sheet(20). When the electrodes(22) are supplied with current, the semiconductor devices(26) generated heat. The heat is transferred to the air via the main coating layers(28,28') and the surface layers(30,30'). Harmful electromagnetic waves are shielded by hardwood charcoal in the surface layers(30,30').