Thin-film chips ideal for projection applications

Osram Opto Semiconductors has increased the efficiency of red thin-film light-emitting diodes (LEDs) by 30 per cent, opening up applications in general illumination and projection.

The latest generation of thin-film chips, also suitable for use in the industrial sector, benefits from an optimised chip platform that has potential for further improvements.

A red 1mm thin-film chip (InGaAlP) has achieved an efficiency of 119lm/W at an operating current of 350mA (136lm/W at 70mA).

The chip is packaged in a Golden Dragon Plus LED and emits at a wavelength of 615nm (l dominant).

This advanced technology efficiency has been measured at 44 per cent at 350mA (49 per cent at 70mA) and exceeds 50 per cent efficiency at 350mA for a wavelength of 642nm.

A higher efficiency yields a greater output for the same current and lower power consumption in all relevant applications.

With this advanced technology, new design options are possible as fewer chips are needed for the same output requiring less space.

In addition, there is 50 per cent less wasted thermal heat that needs to be removed, which, in turn, reduces the required cooling.

As brightness increases, the light sources can be made smaller.

The improved performance of this thin-film LED technology expands the possible applications for this light source.

For example, high-efficiency red can deliver warm-white LED solutions with better colour rendering and improved energy balance by colour mixing instead of the typical phosphor conversion of blue light.

Dr Wolfgang Schmid, who is responsible for developing this chip technology at Osram Opto Semiconductors, said: 'This will benefit all applications that use high-efficiency red LEDs, particularly projection applications.

'We expect to start equipping LED products with the new thin-film chips in about a year's time,' he added.

Back to top