| 摘要 |
PURPOSE:To obviate an invasion of an unnecessary matter and generation of a dewdrop, and to exactly execute an image photographing extending over a long period of time by providing a cover for covering an optical system, forming an opening part which is opened and closed through a shutter, between an optical lens and an object, and jetting pressure air of high/low pressure in accordance with opening/closing of the opening part. CONSTITUTION:When a vision sensor 60 is not driven, it is prevented that exhaust gas and dust, etc. adhere to a lens 62, by closing an opening part. Also, by driving a protecting device 63 for an optical lens, pressure air from a supply source 90 is brought to a pressure reduction by a throttle valve 96 after dust is removed by a filter 92, and low pressure air is led out to the shutter 68 side from duct lines 80a, 80b, and prevents dust, etc. from invading the inside of a cover member. When a motor is driven and a rotary driving axis is rotated, the shutter 68 is oscillated under a driving action of a cylinder 70 and the opening part is opened. Subsequently, the pressure air from a duct line 102s drives a changeover valve 94, and air of high pressure is jetted to the front in the axial direction of the lens 62 through the duct lines 80a, 80b. |
