PATTERN DETECTING DEVICE

PURPOSE:To detect image patterns of various characteristics by the same photoelectric conversion means on the same stage under non-contact state by composing an optical means of plural optical means of plural optical systems and selecting those optical systems according to the image patterns to be read. CONSTITUTION:The kind of a pattern P to be detected is judged by a CPU 26 and one of detection systems 18A-18C which is suitable to the judged kind is set. Then, the stage 10 is driven in two directions by driving systems 12 and 14. Consequently, the pattern P is converted by a photoelectric transducer 20 into an electric picture signal, which is outputted to the CPU 26. The CPU 26 stores this picture signal in a memory 28 and then judges a next image pattern to repeat the same operation or finish the operation. When a detecting means corresponding to the kind of the image pattern on a semiconductor wafer 16 is selected, a corresponding processing means is also selected to perform the optimum processing of the image data stored in the memory 28. Thus various patterns are detected continuously on the same stage.