OPTICAL LOW-PASS FILTER, OPTICAL LOW-PASS FILTER CORRECTION METHOD, CCD SOLID-STATE IMAGE PICKUP ELEMENT, COLOR IMAGE PICKUP DEVICE AND CAMERA

摘要

PROBLEM TO BE SOLVED: To provide an optical low-pass filter which is capable of executing optical low-pass filter correction suitable for pixel arrays of the same colors in image regions of an RGB type and an optical low-pass filter correction method which does not form moire images, etc., even in any of the horizontal direction, perpendicular direction and diagonal direction of the image regions of the RGB type. SOLUTION: The optical low-pass filter is the optical low-pass filter for an image pickup element having the image regions of the RGB type and is formed with phase gratings extending in the diagonal direction in such a manner that the cut-off characteristics corresponding to the Nyquist space frequency of the diagonal direction when the MTF characteristics in the diagonal direction of the image regions are measured. This optical low-pass filter correction method is the optical low-pass filter correction method for the image pickup element having the image regions of the RGB type arrayed with the pixels in the matrix form and executes the correction in the diagonal direction by arranging the optical low-pass filter in such a manner that the phase gratings extend in the diagonal direction of the image regions.