Blinking replaces the double-click

The super low-profile Synios IRED is ideal for eye tracking in mobile devices

The SFH 4770S from Osram Opto Semiconductors is currently the most compact infrared LED (IRED) in the high-power class. Its low height is of particular benefit in smartphones and tablets. The high optical output of typically 1200 milliwatts (mW) and broad emission characteristics make this IRED ideal for facial recognition and eye-tracking systems which can activate applications in response to blinking instead of the usual double-click.

The basis for the new record emitter is the Synios package which Osram introduced some time ago for LEDs in the visible spectral range for automotive applications. The package is extremely compact, measuring only 2.7 mm x 2.0 mm x 0.6 mm, and offers optimum light extraction. The SFH 4770S is the first component in which this package has been used for infrared emitters. Installed in the IRED is a 1 mm2 emitter chip with a wavelength of 850 nanometers (nm) in which two emission centers are provided with the aid of nanostack technology. Overall, the component delivers a typical optical output of 1200 mW at a current of 1 ampere with only one chip

With a height of only 0.6 mm, the SFH 4770S has a lower profile than all IREDs previously available in its output class. It is therefore extremely attractive for designs that call for broad homogeneous illumination in a limited space. This is particularly the case for applications in mobile devices such as smartphones and tablets. “The SFH 4770S takes up very little space”, said Bianka Schnabel, Marketing Manager at Osram Opto Semiconductors. “Compared to the Oslon, previously our most compact high-power IRED, we have managed with Synios to reduce the footprint by almost one third and the height by around one quarter.”

The emission angle of 120° ensures that the target area is evenly illuminated. Even with this emission characteristic, the SFH 4770S achieves a typical radiant intensity of 375 milliwatts per steradiant (mW/sr) at 1 A thanks to its high overall output. This makes the IRED ideal for facial recognition and eye-tracking systems because these systems need the user’s face to be brightly and uniformly illuminated.

The Synios package is also highly suitable for injecting light into external optics or light guides. Another important property for all applications is the excellent thermal stability of the SFH 4770S. Its thermal resistance (Rth) is a maximum of 9 kelvin per watt (K/W).

The Synios SFH 4770S is already available on request for first customer projects. Volume start-up is planned for the end of January 2016.

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