DIAPHRAGM FOR PERFORMING IMAGE POSITION CORRECTION OF A VIRTUAL IMAGE PROJECTABLE ON A WINDSHIELD OF A VEHICLE BY MEANS OF A HEAD-UP DISPLAY

A diaphragm for performing image position correction of a virtual image projectable onto a windshield of a vehicle by a head-up display. A first positioning mark, a second positioning mark, and a calibration mark are attached to a disk of the diaphragm. The disk is transparent at least in the region of the first positioning mark, the second positioning mark, and the calibration mark, so that a first image including the first positioning mark and a first positioning pattern recorded directly through the disk and output on the vehicle side, a second image including the second positioning mark and a second positioning pattern output on the vehicle side, mirrored by a mirror of the diaphragm and recorded through the disk.