| 摘要 |
PURPOSE:To reduce the cost of a device and to unnecessitate adjustment or calibration by receiving two light beams splitted after transmitting through a mask and correlating two received light signals. CONSTITUTION:This device comprises an objective lens 4 focusing on an object 5, an image forming lens 6 forming the image of the light from the object 5 on a CCD sensor 8 and a mask 7 provided on the front side or the rear side of the image forming lens 6 and splitting the light beam from the object 5. The CCD sensor 8 generates a light receiving signal in accordance with two images formed on the CCD sensor 8 by the light beam from the object 5 and a correlator 9 correlating two received light signals generated in the CCD sensor 8 with each other is provided. By automatically moving the objective lens 4 so that the correlated value given by the correlator 9 becomes maximum, focusing on the object 5 is performed. Consequently, the combination of a lens and a mask is used instead of a separator lens. |
