Manual Polarization Axis Control for Eyewear on Headform – PA5 – Lema

The PA5 is a visual inspection device designed to check the correct alignment of polarized lenses on sunglasses positioned on a headform.

Built in compliance with ISO 18526-2:2020 (“Apparatus for the Determination of the Plane of Transmission”), the PA5 allows the eyewear to be tested in the actual “as worn” position, with pantoscopic angle adjustment for maximum accuracy.

The device features individually mounted split-field polarizers, backlit for clear visibility.
By rotating the levers, the operator can determine the polarization axis deviation (in degrees) for each lens.

The sunglasses are placed on adjustable supports on the headform, and the reading is done visually: the operator adjusts the levers until the top and bottom halves of the illuminated field appear evenly lit.

A pointer on a degree-calibrated scale then indicates the exact deviation.

The PA5 includes a calibration plate for precise alignment of the polarizers.
The headform—manufactured according to ISO 18526-5, size 1-M—features adjustable eyewear supports, improving both efficiency and repeatability in daily testing operations.

The PA5 is the ideal solution for lens assembly laboratories and eyewear manufacturers seeking reliable tools for quality control of polarized lenses.

The polarization axis of a lens is the direction along which its polarizing filter lets light pass. This is a key element in the design of polarized lenses, which are usually oriented vertically—about 90° from the horizontal.
This vertical alignment helps block reflected light from flat surfaces like water, snow, or wet roads, significantly reducing glare.

According to ISO 12312-1:2022, the declared polarization axis must not deviate more than ±5° from the vertical (or from a specified direction, if different). The alignment between the left and right lenses in a pair of polarized glasses must not differ by more than 6°.

Our polarization axis testing tools help manufacturers ensuring their lenses meet international standards with precision and ease.