| 摘要 |
PURPOSE:To find the optical performance of a lens to be measured by arranging a movable mirror between the lens to be measured and an edge opening surface and rotating or oscillating the movable mirror and scanning a slit body image illuminated with luminous flux from a light source. CONSTITUTION:The movable mirror 5 which is rotated or oscillated as shown by an arrow is arranged between the lens 1 to be measured and a slit body 2 illuminated with luminous flux from a light source 4. A slit 7 having an edge opening is arranged on the image formation plane 6 of the body 2 formed by the lens 1. A photomultiplier 9 detects the quantity of light of part of a linear image intensity distribution 8 passes through the opening 7. Consequently, the linear image intensity distribution 8 of the body is scanned substantially through the opening 8 and a signal obtained by the photomultiplier 9 is differentiated by a differentiating circuit 10 and processed by Fourier transformation through an arithmetic circuit 11 to find the modulation transfer function MTF of the lens 1 with high precision. |
