Auto focusing lens module and calibrating method thereof

A calibrating method, suitable for an auto focusing lens module, the auto focusing lens module comprising a casing, a photo interrupter and a lens holder, the photo interrupter being fixedly disposed on the casing and having a light-emitting surface and a light-sensing surface opposite to the light-emitting surface, the lens holder being disposed in the containing space and having a first obstacle and a second obstacle, the space between the first obstacle and the second obstacle keeping a calibrating interval;

• the calibrating method comprising:
• moving the lens holder, and defining a home position when the first obstacle is moved to the space between the light-emitting surface and the light-sensing surface;
• keeping moving the lens holder so that the calibrating interval and the second obstacle sequentially pass through the space between the light-emitting surface and the light-sensing surface, and counting the calibrating interval to obtain a counting value when the second obstacle is moved to the space between the light-emitting surface and the light-sensing surface;
• and
• comparing the counting value with a predetermined value so as to calibrate and set a moving scale for moving the lens holder.

An auto focusing lens module, comprising:

• a casing, having a containing space;
• a photo interrupter, fixedly disposed on the casing and having a light-emitting surface and a light-sensing surface opposite to the light-emitting surface;
• and
• a lens holder, disposed in the containing space, wherein the photo interrupter is located on the substantially middle position of a moving range of the lens holder in the containing space and the lens holder has a calibrating obstacle and a calibrating width of the calibrating obstacle is substantially greater than or equal to 2 mm,
• wherein the lens holder is capable of moving to-and-fro along an axial direction to bring the calibrating obstacle to-and-fro passing through the space between the light-emitting surface and the light-sensing surface.