Mask and skin care device including same

A mask comprising:

• a first wiring disposed on a first base layer;
• a piezoelectric element disposed on the first wiring;
• a second wiring disposed on the piezoelectric element;
• a second base layer disposed on the second wiring;
• a protective layer disposed between the first and second base layers and surrounding the first wiring, the second wiring, and the piezoelectric element;
• and
• a control unit for controlling a driving frequency of the piezoelectric element,
• wherein the control unit controls the driving frequency of the piezoelectric element in a frequency band defined as a first range, and
• a temperature of the piezoelectric element is changed by controlling the driving frequency by the control unit,
• wherein the frequency band of the first range includes a resonant frequency of the piezoelectric element, and is lower than an anti-resonant frequency of the piezoelectric element, and
• wherein a temperature of the piezoelectric element when the driving frequency is the resonant frequency of the piezoelectric element is higher than a temperature of the piezoelectric element when the driving frequency is higher than the resonant frequency of the piezoelectric element and is lower than a temperature of the piezoelectric element when the driving frequency is lower than the resonant frequency of the piezoelectric element.