Automatic focusing structure and digital camera module with same

A digital camera module, comprising:

• a lens module including a barrel;
• a holder carrying the lens module and defining a notch;
• a piezoelectric actuator mounted to the lens module and configured for driving the lens module to slide relative to the holder;
• a passive feedback unit configured for providing the movement position or the lens module to the piezoelectric actuator, and the piezoelectric actuator further adjusting the position of the lens module, the passive feedback unit including a resistor, an electrode and a power source connected to each other, the resistor being received in the notch, the electrode slidably contacting with the resistor;
• and
• an image sensor, the image sensor mounted on the holder.

A digital camera module comprising:

• a lens holder including a resistor thereon;
• a lens barrel telescopically received in the lens holder, the lens barrel having a front end and an opposite rear end, at least one lens fixed in the lens barrel, an electrode located on an outer periphery wall of the barrel, the electrode slidably contacting with the resistor, when the barrel slides relative to the holder, the resistance value of the resistor is changed, information of the resistor corresponds to a position information of the barrel;
• an image sensor located facing the rear end of the lens barrel;
• and
• a piezoelectric actuator attached to the rear end of the lens barrel, the position information of the barrel being fed back to the piezoelectric actuator, the piezoelectric actuator being configured for moving the lens barrel by piezoelectric deformation thereof when the piezoelectric actuator is energized.