Electronic Polarization Axis Control on Eyewear – PA3 – Lema

The PA3 is an electronic device designed to verify the correct alignment of polarized lenses once mounted on eyewear.
It uses a polarization sensor for precise detection of the polarization axis, and features an auto-calibration system that runs at every startup using a dedicated calibration filter.

The PA3 provides visual feedback during calibration, while the LCD display shows test results and settings in real time.
Once the device is calibrated, the eyewear is placed on dedicated supports that align the lenses with the built-in sensors.

At the touch of a button, the device performs an automatic polarization check, displaying the results and confirming whether the lens alignment is within ISO 12312-1:2022 tolerance limits.

The PA3 also includes PC-compatible software for saving and managing test data.

Reliable and precise, the PA3 is ideal for lens assembly labs, eyewear manufacturers, and optical quality control specialists— an essential tool for teams who rely on consistent, high-quality results.

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.