Infra Red LEDs For Eye Tracking

Eye tracking in VR and AR is there to reduce the discomfort and dizziness felt by some users when virtual and real perceptions do not match. It is implemented by analysing images from a camera directed at the eye, illuminated by infra-red LEDs, to extract viewing angle and eye movement.

Called Firefly SFH 4030 and SFH 4060, the side-emitting LEDs are 1.0 x 0.325mm and 0.55mm high.

As with many Osram infra-red emitters, they are offered in two wavelengths: “Customers can choose between 940nm [SFH 4030] or 850nm [SFH 4060]. With 850nm, the customers benefit from the high sensitivity of the sensors in this wavelength range. On the other hand, the 940nm version avoids the disturbing ‘red glow’ the user can see,” said Osram.

Which ever wavelength, the devices have a black cap to reduce visual impact when the components are installed.

Operating current is 70mA, where forward voltage (SFH 4030) is typically 1.6V (2V max). Radiant intensity is 2.5 – 12.5mW/sr depending on bin (70mA 20ms).

Maximum power is 140mW.