More light for pico projectors : Green laser diode with high optical output
Osram Opto Semiconductors is getting around 60 percent more light from its new PL 520B green laser diode. Pico projectors that only use green lasers achieve a system brightness of up to 20 lumen. The PL 520B has an extremely stable response to changes in temperature and therefore contributes to good image quality.
The green PL 520B single-mode laser provides an optical output of 80 milliwatts (mW) at a typical current of 200 milliamps (mA) and a voltage of 6.4 V. Compared to its predecessor with an output of 50 mW, developers were able to increase the efficiency of the component from five to seven percent. This greater efficiency reduces energy consumption, which benefits mobile battery powered devices in particular. The PL 520B is used mainly in very small projection units. It can be found in portable mini projectors and as embedded solutions in cameras, smartphones and tablet computers. Projectors with only one green laser in the light source can now achieve a system brightness of up to 20 lumen. Up to 40 lumen can be achieved for systems with two green diodes.
Excellent thermal stability
The high efficiency of the laser diode also contributes to much improved thermal behavior. It does not heat up as much at high operating currents. The laser threshold is reduced to a typical value of 40 mA. Its good thermal stability simplifies control of the laser and ensures that the laser threshold remains more stable if there is a rapid change from high to low operating currents. The PL 520B is mounted in a compact TO38 package. There is also a TO56 version. The package is a little larger but offers benefits in terms of thermal connection and simplifies thermal management in many applications.
On the way to head-up displays
The excellent thermal behavior of the new laser diode paves the way for future applications in cars. “The performance of the PL 520B is a first milestone along the road to its use in laser-based head-up displays”, said Stephan Haneder, Marketing Manager at Osram Opto Semiconductors. “We are currently working on further improving the thermal behavior of the laser diode to achieve reliable operation also at an ambient temperature of 85°C.”
