| 摘要 |
PROBLEM TO BE SOLVED: To optimize a thresholding reference level necessary to align in a full automatic bonder for wiring based on positioning through a photographed image mounting a semiconductor chip in a lead frame. SOLUTION: Image data, sent by a means 21 for imaging an object to be bonded in the drawing up to immediately prior to starting of bonding by a wire bonder is stored in a video memory 25 via a shift register 24 without intermediary of a comparator 23. A thresholding reference level of the image is obtained according to a discriminating function by using a CPU 26 from a histogram of the density of the data. Thus, the reference level is input to the comparator as an initial thresholeling reference level 502 and is provided as a sample reference level. In addition, after starting bonding, even when an aligning operation becomes impossible due to change in light quantity, is operation is conducted again immediately thereafter, optimum thresholding reference level is calculated, and thereafter a multivalued image is threshold processed, based on the optimum reference level. |
