Sensor

A method of temperature sensing using a temperature sensor device, said device comprising a plurality of temperature sensor cells, each temperature sensor cell comprising an electrical temperature sensor, said electrical temperature sensor comprising:

• a liquid crystalline material capable of existing in a crystal state, a liquid crystal state or a liquid state;
• first and second electrically conductive contacts, having a spaced relationship there between, which contact the liquid crystalline material;
• and an electric property measuring device, electrically connected to the first and second contacts and arranged to measure an electric property of the liquid crystalline material;
• wherein the liquid crystalline material has a transition temperature T at which it undergoes a phase change between polar and non-polar states, the phase change between polar and non-polar states occurring within the liquid crystal state and causing a change in said electric property of the liquid crystalline material;
• and wherein the transition temperature T of the liquid crystalline material in at least two of the temperature sensor cells is different;
• the method comprising:
• measuring said electric property of the liquid crystalline material in each temperature sensor cell via the first and second contacts;
• determining whether the transition temperature for each temperature sensor cell has been reached as a function of the measured electric property;
• and
• detecting the sensed temperature as lying between the transition temperatures of a first temperature sensor cell and a second temperature sensor cell, the transition temperatures of which are adjacent within a temperature range, wherein the measured electric property of the first temperature sensor cell indicates that the transition temperature has been reached and the electrical property of the second temperature sensor cell indicates that the transition temperature has not been reached.