| 摘要 |
PURPOSE:To make the spacial frequency characteristics of a lens to be examined measurable with high accuracy and make operation simple by forming the image of an infinite object point on the face of an optical grating and rotating the optical grating within the plance inclusive of optical axis. CONSTITUTION:While the image of the infinite object point formed by a lens 3 to be examined is being scanned with an optical grating 5, the contrast of the image is photoelectrically measured 14, whereby the spacial frequency characteristics of the lens 3 are measured. In this case, the image of the object point is formed through the lens 3 on the face of the rectangular wave grating 5, and while the image of the image point 8 is being scanned at an equal speed within the plane inclusive of an optical axis 6, the contrast 15 of the image with respect to a field angle theta is photoelectrically measured. |
