Patent ID: 7697377

Claim:
A portable timepiece, comprising: an atomic oscillator configured to generate and output a reference clock signal, the atomic oscillator having an atomic oscillator unit and a control unit; a timepiece module configured to operate based on the reference clock signal; a power source configured to supply power to the atomic oscillator and the timepiece module; a timepiece case configured to accommodate the atomic oscillator, the timepiece module, and the power source; a thermal separator configured to separate thermally the atomic oscillator and the timepiece module, the atomic oscillator unit being embedded by the thermal separator, the atomic oscillator including a cell in which atoms are sealed, a heater for heating the cell, and a control device in which the point of reference is a frequency being equivalent to the energy difference between the energy level of the ground state and the energy level of the excited state by excitation of the atoms in the cell, the control device configured to control the heater and maintains the cell at a specific temperature.