Eye don't believe it: Iris scanner protects your home

27th February 2017

Alice Matthews

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The new SFH 4787S Infrared LED (IRED) for iris scanners illuminates the eyes so evenly that the software identifying the iris pattern now hardly needs to correct artefacts. Like its predecessor (SFH 4786S), its direction of emission is slightly angled rather than vertical, thus simplifying the design process by eliminating the usual mechanical aids.

Osram Opto Semiconductors is presenting the new SFH 4787S IRED at the Mobile World Congress. Iris recognition is among the most reliable biometric identification methods available today. With this safeguard, iris scanners illuminate the user’s eyes with infrared light and a camera takes a photograph. Special software then analyses this photo to detect the iris pattern, which is unique to each individual. Once confirmed, the device is unlocked for the user.

Two years ago, Osram Opto Semiconductors was first to market an infrared LED (the SFH 4780S) that brought this technology to smartphones and other mobile devices. This was followed by a version with a slightly angled direction of emission (SFH 4786S), which meant that designers no longer needed mechanical aids to tilt the entire LED to align the angle of emission with the camera’s field of view.

Even illumination simplifies processing
The key feature of this third-generation Osram IRED for iris recognition is its flat intensity distribution, optimising the reflector and lens to ensure virtually constant intensity across the emitted light beam. With this technology advance, the brightness differences in the camera images originate only from the iris pattern and are not additionally generated by a gradient in the illumination. The software then needs to correct fewer artefacts when determining the iris pattern, increasing accuracy in analysis and detection.

Apart from this, the SFH 4787S is almost identical to its predecessor, the SFH 4786S. Both are based on the compact 3.5x3.5x1.6mm Oslux package. A wavelength of 810nm delivers high-contrast images for all eye colours. The emission direction is tilted by 8°, while the emission angle is ±18°. The optical output of this emitter is 720mW at a current of 1A, with a radiant intensity of 1,000mW/sr.

Industrial applications gaining ground
The impetus to develop more compact and reliable iris scanners was driven by the need for dependable solutions to safeguard mobile devices from unauthorised access. Gradually, the technology is making its way into other sectors. “Access control as a whole is becoming increasingly important and iris recognition remains one of the most reliable methods available,” explained Eric Kuerzel, Product Marketing Manager at Osram Opto Semiconductors. “There are a variety of industries following in the footsteps of the consumer markets by incorporating iris recognition for access control and other functions.”