Apparatus and method for controlling auto focus of camera module

A method of controlling an auto focus of a mobile terminal, the method comprising:

• moving a lens unit of the mobile terminal by applying a first current or voltage signal to a moving coil of the mobile terminal, wherein a second current or voltage signal is induced to a fixed coil of the mobile terminal by electromagnetic induction between the moving coil and the fixed coil, the second current or voltage signal being varied according to a distance between the moving coil and the fixed coil;
• sensing an image incident on the lens unit according to the movement of the lens unit;
• processing the sensed image;
• detecting a temperature of the fixed coil;
• determining a position of the lens unit for the auto focus based on the second current or voltage signal, the processed image, and a difference between a reference temperature and the detected temperature of the fixed coil.

A method of controlling an auto focus of a camera module, the method comprising:

• moving a lens unit of the camera module by applying a first current or voltage signal to a moving coil of the camera module, wherein a second current or voltage signal is induced to a fixed coil of the mobile terminal by electromagnetic induction between the moving coil and the fixed coil, the second current or voltage signal being varied according to a distance between the moving coil and the fixed coil;
• sensing an image incident on the lens unit according to the movement of the lens unit;
• processing the sensed image;
• detecting a temperature of the fixed coil;
• determining a position of the lens unit for the auto focus based on the second current or voltage signal, the processed image, and a difference between a reference temperature and the detected temperature of the fixed coil.

A camera module for an auto focus, the camera module comprising:

• a fixed unit having a hole formed therein;
• a magnet placed inside the fixed unit;
• a lens unit including at least one lens and configured to move;
• a moving coil placed on the lens unit;
• a fixed coil;
• an image signal processing unit processing an image provided by a sensing unit;
• and
• a controller configured to:
• provide a first signal to the moving coil, wherein a second signal is induced to the fixed coil by electromagnetic induction between the moving coil and the fixed coil, the second signal being varied according to a distance between the moving coil and the fixed coil,
• detect a temperature of the fixed coil;
• and
• determine a position of the lens unit for the auto focus based on the second current or voltage signal, the image processed by the image signal processing unit, and a difference between a reference temperature and the detected temperature of the fixed coil.