| 摘要 |
PURPOSE:To provide a small sized portable gas detector having high light collection efficiency and auto-focus function which can detect concentration of gas at any place. CONSTITUTION:The laser light reflected on an outer target is condensed through a condenser lens 2 and a part thereof is further reflected on a half mirror 51. A linear image sensor 53 detects the position illuminated by the reflected laser light through a focus lens 52 and the imaging position of laser light passed through the condenser lens 2 is operated based on the position thus detected. A step motor 55 is then rotated to shift a sleeve 5 to the imaging position through a pinion 54 and rack 56. |
