METHOD AND APPARATUS FOR PRODUCING NONGRINDING LENS BY LIQUID-DROP METHOD

PURPOSE:To obtain nongrinding glass free from striae on the glass surface in the process of forming lens by liquid-drop method by detecting, cutting and removing the glass threads generated with glass liquid drops by a specified means. CONSTITUTION:The glass heated and melted in dropped by gravity through a platinum nozzle 1 on the lower mold 7 heated to the temp. lower than the softening temp. of glass. In this case the glass is dropped in such a state that the liquid drop part 2 is connected with the thread part 3 directed to the nozzle 1. Two pairs of photodetectors 4A, 4B, 5A, 5B detect the liquid drop 2, and the position of the liquid drop and the thread are calculated by an arithmetic part 15 and a thread cutting unit which consists of nipping parts 8 and a nipping plate driving part 9, etc., and is acted according to the calculated result and nips the thread 3 and, at the same time, the nipping plates 8 are moved upwards along a rail 11 by the operation of an actuator 12 so that the thread 3 is attracted by the weight of the liquid drop 2, which falls on the lower metallic mold 7 where the surface temp. is swiftly lowered to a lower temp. than the softening temp. Then, an upper metallic mold is operated to carry out the pressing formation. On the other hand, the cut thread is sucked and removed by a suction unit 13.