| 摘要 |
PURPOSE:To calculate easily the MTF value of a pinhole every time a lens to be inspected is changed and measured, and to improve a measurement speed by monitoring the focal length of each lens to be inspected through a personal computer all the time. CONSTITUTION:Light from a lighting stand 26 is collimated by a collimator lens 43 and focused on the surface of a Ronchi grating 29 through the lens 44 to be inspected. An axis 45 of rotation is aligned almost to the 2nd principal point of the lens 44 and a turntable 30 is rotated clockwise and counterclockwise. Then, the focus spot scans on the Ronchi grating 29 and light transmitted through the grating is converted by a photoelectric conversion stand into an electric signal, calculating the MTF vlalue of the image by it. On the other hand, the distance between the position of the principal point of the lens 44, i.e. the position of the axis 45 of rotation of the turntable 30 and a sensor 34 is already known, so this known value is added to the position relation between the sensor 34 and a scale 33, i.e. the value of a display device 36 to find the focal length of the inspected lens 44. The personal computer 38 receives signals from a photoelectric conversion part 31 and the sensor 34 to find and output the MTF value of the lens. |
