Reticle projection system for video inspection apparatus

Abstract

The reticle of a single magnification reticle projector mechanism of a multiple magnification video inspection apparatus may comprise a liquid crystal display (LCD) module the pixels of which are selectively energized by a conventional plug-in video card that forms part of a CPU. As the magnification setting of the apparatus is changed, the CPU causes a corresponding change in the size and spacing of the pixels that are energized. The energized pixels form clear or transparent dots on the reticle, while the remaining, unenergized pixels cause corresponding areas of the reticle to remain opaque. Alternatively the reticle is provided with a plurality of viewing areas or fields of different size, each area comprising a plurality of spaced openings or transparencies of equal size, and progressively larger fields having progressively larger openings. The reticle is mounted for lateral adjustment in the mechanism, and depending upon the selected magnification of the apparatus, the reticle is shifted either manually or under control of the CPU selectively to place the center of any one of the different fields into registry with the axial centerline of the reticle projector. In this way when the magnification is changed a corresponding change is effected in the size of the openings of the projected reticle image.