Development of multi head review system using the planar stage

This paper proposed the multi head review system using the planar stage to increase the productivity about inspection in flat panel display industry. This system uses the planar stage having multi head against of conventional review system having single head gantry. Though the multi head system is able to increase productivity, it has the hazard of collision by multi head. Therefore, this paper also proposes the collision avoidance algorithm. This algorithm uses division of inspection area and simultaneous movement of each head. From the calculated coordination for each head the correct position data of defect is able to be obtained. This system is effectively implemented by it without collision. The performance of proposed system is verified with simulation and experiment. Through the simulation, this paper calculates and compares the tact time of multi head review system and gantry review system about inspection of same defect. Also, the variation of productivity is verified according to the distribution of defect. This paper uses the planar stage having 4 head for experiment. This system shows that the productivity about inspection is increased than conventional review system.