Instead of the usual lens, OSRAM Ostar Stage LEDs have a flat glass cover with an anti-reflective coating, giving the LED a much flatter profile. It is now only 1.23 mm high – one quarter of the usual height. Spotlights can therefore be made much more compact.
The glass cover on the new LEDs has been optimized 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 customer optics enables a very narrow beam of light (+/- 9°) to be produced. This beam is smaller by factor 2 than for spotlights based on plastic-encapsulated LEDs. This optimum bundling of the light increases the luminance of the spotlight also by factor 2.