Horological movement provided with an oscillator comprising a piezoelectric spring

A horological movement comprising:

• an analogue time display, a gear train, a barrel driving the analogue display via the gear train, and an oscillator formed of a resonator, comprising a balance and a piezoelectric spring, and a mechanical escapement coupling the balance to the gear train, the piezoelectric spring being formed at least partially of a piezoelectric material and comprising at least two electrodes at least one electrode of which is connected to an electronic control circuit, the piezoelectric material and said at least one electrode being arranged so as to allow the application, managed by the electronic control circuit, of an electrical stress on the piezoelectric spring;
• wherein the electronic control circuit is arranged to be able to be connected to an electric energy source and to be able to control the application, at least occasionally, of a power supply voltage to said at least one electrode so as to excite the oscillator to obtain a functional oscillation of the resonator and then to maintain said functional oscillation;
• and
• wherein the mechanical escapement is configured so as to be an escapement for counting the alternations of the functional oscillation, thus in order to pace the running of the horological movement, without the resonator being able to receive from the barrel via said mechanical escapement enough mechanical energy to maintain the functional oscillation.