Osram Opto Semiconductors has introduced the new Oslux SFH 4786S infrared LED (IRED). According to the company, the new IRED that measures just 1.6mm high enables less complex and lower profile iris recognition systems. The new IRED is about one-third thinner than its predecessor and its emission is slightly angled, so mechanical aids to ensure correct geometrical alignment are not necessary.
Osram Opto notes that recognizing different iris patterns from one person to the next is among the most reliable biometric identification methods. Smartphone makers have recently adopted the technology to prevent unauthorized access. In 2014, Osram Opto Semiconductors intro cued the Oslux SFH 4780S. The company claims that the Oslux SFH 4780S was the first IRED that enabled compact and reliable iris scanners for mobile devices.
The company optimized the 2.4 mm high SFH 4780S primarily for maximum light extraction. However, the new Oslux SFH 4786S features the same high light extraction, but the company reduced its height to just 1.6 mm for very low-profile emitters for designs with severe height constraints. The SFH 4786S now features an 8° tilt in the emission direction, which is useful for a field of view of the camera mounted a slight distance away. Osram Opto contends that the overall system performance is significantly better than one whose emission is angled slightly upwards.
“Up to now, mechanical means have been used in iris scanners to tilt the IRED slightly,” said Chris Goeltner, Product Marketing Manager, IR, at Osram Opto Semiconductors. “However, this additional expense is no longer needed with the SFH 4786S. This greatly reduces the level of complexity in designing iris scanners.”
The new IRED also provides a somewhat broader emission angle of +13°, allowing a larger area to be illuminated at the working distance for iris scanners in mobile devices. At a current of 1 amp (A) the radiant intensity of the SFH 4786S is typically 1,750 milliwatts per steradian (mW/sr). Like the SFH 4780S, the SFH 4786S emits light at a wavelength of 810 nanometers (nm), enabling high-contrast images for all iris colors. The chips are of Nanostack design which combines two emission centers per emitter, resulting in maximum optical output. Osram Opto based both IREDs are based on the very efficient Oslux package, that focuses the light very tightly an internal lens and a reflector.
The company points out that the new IRED can deliver very high radiant intensities and also be extremely easy to process thanks to its flat surface. The package has the low thermal resistance of 25 kelvin per watt (K/W). The SFH 4786S is available upon request. Osram Opto Semiconductors plans to begin volume production at the end of January 2016.