Detecting an object having an elevated temperature

摘要

A detector 10 for detecting an object 18 having an elevated temperature comprises a thermochromic layer 13 comprising thermo-chromic material that changes between opaque and transparent states according to increased temperature. Light travels through the thermo-cromic layer 13 and a light conducting body 12 to a light detector 13. Object 18 can be a foreign body such as a coin that is heated by eddy currents induced in it by the electromagnetic field of a an inductive energy transfer device for charging electric vehicles. Thermo cromic 13 layer can be formed on a transparent protective cover 14 and mechanically connected to a planar surface of light transmitting body 12. Light passing through the thermo chromic layer 13 can be can be ambient light or light from a light source (fig 5, 24). The detector can be protected by an opaque cover 11.