A particle retrieving apparatus

摘要

A particle retrieving apparatus (10) is provided for individually retrieving particles (58) such as diamond particles using a reciprocating vacuum needle (48). A balance arm (20) is provided having a hopper (46) at its free end for receiving the diamond particles. The balance arm is adjusted so that it is in a position of equilibrium. As the needle tip (48A) contacts a particle (58A), the balance arm is displaced downwardly, with such downward displacement being sensed by an opto-sensor (38) which is thereby used to sense the contact position (81) of the needle as it comes into contact with the diamond particle (58A). The contact position is recorded at a micro-processor-based controller (52), which is then used to control the subsequent motion of the needle (48) in the next retrieval cycle on the basis of the recorded contact position.