Limited Installation Space? A 90° Prism Can Help Redirect the Optical Path

In conventional machine vision systems, the camera, lens, and object are typically arranged along the same optical axis.

For top-down inspection, the lens must be installed above the object. If the working distance is 200 mm, the lens length, camera size, and mounting structure can make the vision module too tall for the equipment.

A common solution is to add a 90° right-angle prism between the lens and the object. The prism changes the direction of light propagation without changing the lens's primary working-distance parameter. A formerly vertical optical path can be redirected horizontally, moving the space requirement from above the object to the side.

Before implementation, check the prism's clear aperture against the lens beam, possible vignetting, prism angle, and mechanical stability. Build and test the assembly to confirm field of view, image quality, and installation space.

Machine-vision selection is not only about finding a lens with the right specifications; a deployable solution must match optical performance to mechanical structure. Sometimes the answer is not a new lens, but a different optical-path direction.