Osram Opto Semiconductors GmbH of Regensburg, Germany says that its latest Ostar Stage LEDs offer a high luminance of 48 million candelas per square meter (48Mcd/m2 , at a drive current of 900mA) as well as tunable color tones from cold white to warm white. Combined with their low-profile design and glass cover with its anti-reflective coating, they provide the basis for compact spotlights with an extremely narrow beam, the firm says, suiting use in moving head spotlights on stage, for booth lighting at trade fairs and for architectural lighting.
Two warm-white and two cold-white chips, arranged diagonally in the package, not only enable colors to be mixed at the component level but also allow all white tones between color temperatures of 2700K (warm white) and 10,000K (cold white) to be produced with appropriate control. The LED achieves a high color rendering index (CRI) of 94 for warm white and 74 for cold white.
Instead of the usual lens, the LEDs have a flat glass cover with an anti-reflective coating, making them suitable for injecting the light into lens systems. Its etendue (the emission angle/area ratio of the emitting light surface to the projected light surface) in conjunction with external optics is retained, enabling a very narrow beam of light (+/-9°) to be produced. This beam is smaller by a factor of 2 than for spotlights based on plastic-encapsulated LEDs, so the luminance of the spotlight is greater by a factor of 2.
Due to the glass cover, the Osram Ostar Stage LED also has a much lower profile than previous standard components. At 1.23mm its height is only a quarter of the usual component height and its footprint is only 5.9mm x 4.8mm, so spotlights can be made very compact.
Picture: Osram’s latest Ostar Stage LED.
All versions of the Ostar Stage are based on the Ostar SMT platform and are suitable for standard solder processes. The chips are fabricated using Osram’s latest thin-film technology, so almost all the light produced internally is emitted at the top. The LED hence suits use with external optics. In continuous operation (DC) the chips can handle an operating current of up to 900mA, giving maximum brightness of 390lm in cold white (10,000K) and 210lm in warm white (2700K). At a typical value of 1.8K/W the thermal resistance is very low and heat removal is therefore no problem, says the firm. In constant use the LEDs will last for more than 50,000 hours, giving moving heads and architectural fixtures a long life.
The LEDs can be used in spotlights of any size, from small stage spots to large moving heads. “Three versions of the Osram Ostar Stage LED are available, the Multi Color (RGBW), the pure white and now the tunable white,” says Wolfgang Schnabel, LED Marketing Industrial Applications at Osram Opto. “The range of applications is therefore now greater than ever before. With so many colors and configurations, lamp designers have a virtually unlimited set of options.”
Osram Opto is showcasing the Ostar Stage LED in Hall 9.0, Stand D10 at the Prolight + Sound 2013 event in Frankfurt, Germany (10-13 April).
