| 摘要 |
PROBLEM TO BE SOLVED: To increase focusing speed by eliminating a waiting time before the start of a signal processing time corresponding to the integration time of analog detection signals outputted from a light receiving element. SOLUTION: After having integrate-processed, in an integration circuit 30, the analog detection signals corresponding to the light amount of the luminous flux from a specimen S received by a light receiving sensor 21 through an observation optical system, the signals are converted into digital values for a constant processing time Tc by an A/D converting section 31 to conduct focusing judgement. At that time, the amount of light received is determined on the basis of digital range signals A and B corresponding to the amount of light received by the light receiving sensor 21 and setting changes are respectively made for the integration time at the integration circuit 30 and the starting time of the A/D conversion at the A/D converting section 31 based on optical amount determination signals "0", "1", ... or "5". COPYRIGHT: (C)2005,JPO&NCIPI |
