High Brightness Leds

Light Emitting Diodes (LEDs) are light sources based on semiconductor devices. LEDs are used for a broad range of applications, like backlight illumination of mobile phones, displays, traffic signals, car lamps, projectors, general illumination, and so on. LEDs offer various advantages compared to other light sources, which include their long life time, low lifecycle costs, very compact size, ease of implementation into devices, and very high efficiency. The use of LEDs can save up to 85% in energy consumption compared to standard light sources like tube lights or light bulbs.

Semiconductor materials used to manufacture LEDs have a relatively high refractive index compared to air. This is the reason why only light beams at low angles normal to the surface can exit the device. This effect can be avoided by patterning the surface with feature sizes in the same order of magnitude as the wavelength of light that is emitted by the LED. In this way, the out-coupling of the light and therefore the efficiency of the LED can be significantly improved.

Various types of LEDs are currently available. These include narrow band emitting LEDs with wavelengths spanning from red to blue or broadband emitting LEDs as white light source for general illumination. LEDs are fabricated by epitaxial growth of an optical active layer on compound semiconductor material. The wavelength of the final LED is determined by the semiconductor material type and arrangement of the grown layers. The total efficiency of LEDs can be dramatically increased by implementing efficient and uniform cooling, which amongst others is strongly determined by package design.

WBS offers a wide range of specially adapted products and processing technologies for the fabrication of highly efficient LEDs within its semiconductor solutions portfolio. WBS provided thin-wafer handling solutions as well as UV-imprinting lithography for patterning the top surface of a substrate.