TEMPERATURE SENSOR AND ELECTRO-OPTICAL DEVICE

PROBLEM TO BE SOLVED: To provide a temperature sensor which achieves highly-reliable measurement.SOLUTION: A temperature sensor includes a measurement cell measuring temperature, and the measurement cell includes a ring oscillator in which an odd number of inverters are circularly connected. Each of the inverters includes a first conductivity type thin film transistor and a load element. The first conductivity type thin film transistor has lightly doped drain structure or offset structure. A transmission frequency of the ring oscillator strongly depends on the temperature, so that temperature measurement can be performed with high accuracy.