Infra-red, multi-die emitters let surveillance cameras see 6x further

August 22, 2014 // By Graham Prophet
The first 4-die infrared emitters emit six times previous flux densities from a 7 x 7 mm package.

LED Engin has four new families of Dual Junction infrared (IR) emitters, including the first 4-die versions. Single-die types deliver 70% more output than typical single junction IR emitters. In both product families each die has two serially-connected junctions, creating two radiant surfaces and boosting output. A continuous 5A pulse drive capability means that they can produce a short output burst for even greater range. The emitters are designed for IR systems operating at up to 150m.

LZ1 and LZ4 emitters come in 850 nm and 940 nm variants and produce 1.15W and 4.5W flux output at 1A drive current, respectively. The packages are tiny: 7 x 7mm for the LZ4 and 4.4 x 4.4mm for the LZ1, enabling the design of very small, discreet fixtures. The emitters feature thermal resistance 50% to 75% lower than competing parts: 6.0°C/W for single-die and 2.8°C/W for four-die products, thanks to a proprietary CTE matched, multi-layer ceramic substrate. It means that smaller heat sinks can be used, again facilitating more compact fixtures.

The surface mount ceramic packages have integral glass primary lenses, which are more robust than moulded silicone types and do not degrade over time. The package materials are optimised for thermal and optical performance, ensuring reliable, consistent operation throughout the emitters' lifetime, particularly in tough outdoor environments with high ambient temperatures and high humidity.

A suite of complementary total internal reflection (TIR) lenses, in a choice of beam angles from 8 to 40 degrees enables fixtures to be designed for narrow, longer-distance or wider, shorter-distance beams.

“LED Engin is addressing a number of fast-growing markets for infrared technology by creating emitters that lead the industry in terms of flux density, reliability and sustained high performance. Equipment manufacturers in established markets such as surveillance, transportation and machine vision, and newer businesses in biometrics and gesture recognition, are all looking for ways to differentiate their products through improved performance, smaller size and lower