Barrel driving mechanism and image pickup device thereof

An image pickup device, comprising:

• an image sensor, installed inside the image pickup device;
• a barrel driving mechanism, comprising:
• a fixing-barrel, being a hollow barrel-shaped structure, and having a first groove formed on an internal wall of the fixing-barrel, and the first groove having a first stop-position, a first position, and a third position, and a slanted groove extending from the first stop-position to the first position, wherein the fixing-barrel is fixed onto the image pickup device and a part of the first groove between the first position and the third position is a first slanted groove;
• a driving-barrel, being a hollow barrel-shaped structure, disposed in the fixing-barrel, and having a second groove formed on an internal wall of the driving-barrel, and the second groove having a second stop-position, a second position, and a fourth position, and a slanted groove extending from the second stop-position to the second position, and having a first guiding protrusion formed on an external wall of the driving-barrel and inserted into the first groove, such that when the driving-barrel is rotated, the driving-barrel is moved a first axial distance, wherein a part of the second groove between the second position and the fourth position is a second slanted groove;
• and
• a moving-barrel, being a hollow barrel-shaped structure, disposed in the driving-barrel, and having a second guiding protrusion formed on an external wall of the moving-barrel and inserted into the second groove, such that when the driving-barrel is rotated, the moving-barrel is moved a second axial distance, and the total displacement of the moving-barrel is equal to the sum of the first axial distance and the second axial distance;
• and
• a focusing lens group, installed between the moving-barrel and the image sensor;
• wherein when the driving-barrel is rotated, the first guiding protrusion of the driving-barrel is moved a third axial distance from a the first position to the third position along the first slanted groove, and the second guiding protrusion of the moving-barrel is moved a fourth axial distance from the second position to the fourth position along the second slanted groove, and the total displacement of the moving-barrel is the sum of the third axial distance and the fourth axial distance, and the displacement of the third axial distance plus the fourth axial distance is a displacement of a second-stage focusing of the barrel driving mechanism.