Perger prism

However, in contrast to the traditional double Porro prism, it leads to a significantly reduced eyepiece/objective axis offset.

[1][2][3] Dr. Andreas Perger patented the inversion system in 2011, and it was initially used in the Geovid HD laser rangefinding binoculars (2013 third generation) from the manufacturer Leica.

Then the first and last reflecting surfaces were tilted so that the beam has an angle of incidence that exceeds the 45° that is usual in a Porro prism.

[9] The manufacturer who commercially offers this optical system in binoculars claims good brightness and a light transmission of over 90 percent in its 2020 models.

Since its invention, the patented Perger prism optical design found commercial application on a small scale in some Leica binoculars.