LED is designed for head-up displays

July 21, 2015 // By Christoph Hammerschmidt
Osram Opto Semiconductors has developed the Oslon Compact CL, a high-power LED with a colour coordinate that has been specially matched to TFT displays and the relevant white point requirements. A ceramic converter ensures that the colour locus remains constant even at high temperatures. This high-power light source with its compact package is ideal for use in head-up displays.

When it comes to automotive HMIs, head-up displays are, despite isolated criticism, regarded as a technology of the future. LED manufacturer Osram now has announced the Oslon Compact CL, a high-power LED with a colour coordinate that has been specially matched to TFT displays and the relevant white point requirements. A ceramic converter ensures that the colour locus remains constant even at high temperatures. With an extremely compact footprint of just 1 mm 2, this light source is ideal for use in head-up displays.

Head-up displays (HUDs) offer many significant advantages for car users. Drivers are less distracted and therefore enjoy greater safety. Relevant information such as current speed, warnings, satnav instructions and infotainment data appear directly in the field of vision. Drivers can therefore keep their eye on the road and at the same time receive important information.

The quality of a HUD depends largely on the light source used. TFT displays typically use white LEDs as the light source offer impressive performance, with full-colour display and excellent contrast. The Oslon Compact CL chip has a number of properties that make it ideal for use in head-up displays. Its extremely compact package measures only 1.9 mm x 1.5 mm x 0.75 mm so the LED can be arranged very close to the TFT display (< 100 µm). This results not only in high efficiency and excellent optical characteristics but also in a small mounting depth, which is a great advantage in the cramped interior of vehicles.

The colour coordinate in the colour triangle is cx 0.28/cy 0.25, producing a slightly bluish white. TFT displays filter out the blue component, leaving a pure white from which the entire color spectrum can be generated. As a ceramic component, the Oslon Compact CL has only a small thermal resistance of 8K/W. The resultant heat is quickly dissipated and the color coordinate remains constant even at high temperatures. There are no color