Light source for vision measuring instrument and positioning system using the same

A positioning system for aiming a primary image capture unit of a vision measuring instrument at a selected micro region of an object to capture an image of said selected micro region for measuring, the positioning system comprising:

• a light source configured to be attached to the primary image capture unit to illuminate the object;
• an auxiliary image capture unit secured to the light source;
• a display unit capable of showing images captured by the primary image capture unit and the auxiliary image capture unit, respectively;
• and
• a processing unit coupled to the primary image capture unit, the auxiliary image capture unit, and the display unit;
• wherein the processing unit is capable of controlling a movement of the primary image capture unit with regard to the object, thereby making the primary image capture unit aim at said selected micro region.