▎ 摘　　要

NOVELTY - The device (100) has a first transparent heating unit (110) including a first transparent heating element (111). A second transparent heating unit (120) includes a second transparent heating element (121). A folding unit (130) is provided between the first transparent heating element and the second transparent heating element. The first transparent heating element and the second transparent heating element are graphene thin films. The graphene thin film comprises a single or multiple graphene layers. The graphene thin film is doped with a dopant. The first transparent heating unit comprises a first transparent substrate (112) provided with the first transparent heating element. USE - Variable heating device e.g. variable transparent toaster for baking meat such as pork and beef, fish such as mackerel and mackerel. ADVANTAGE - A portion for heating an object is transparent, so that a process in which the object is heated can be easily checked. A portion for heating an object is transparent, so that hygienic management may be easy. The variable heating device is deformed through a folding unit and can easily heat various objects. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view schematically showing a folded state of the variable heating device. Variable heating device (100) First transparent heating unit (110) First transparent heating element (111) First transparent substrate (112) Second transparent heating unit (120) Second transparent heating element (121) Folding unit (130)