At the Vision Congress in Paris (14-15 October), Osram Opto Semiconductors GmbH of Regensburg, Germany showcased an LED for car headlights with luminance three times that of existing versions, so that a single LED can be used to provide a complete low beam. Previously, several LED chips have been needed, depending on the design and the type of LEDs used.
The high brightness is the result of a combination of the firm’s UX:3 chip technology, ceramic conversion technology and high-current technology used in projection applications. In future it will be possible to design much smaller headlights, with every lighting function smaller than a box of matches, says Osram Opto.
A low-beam unit measuring only 30mm x 50mm generating 1400 lumen from a single LED chip as its light source could be a reality in only a few years time, Osram reckons. At 200 megacandelas per m2, the latest LED has three times the luminance of existing LEDs for these applications and loses less than 10% of its intensity even at high operating temperatures of 85°C.
“In developing the LED we applied our extensive experience in projection applications to combine the high-current technology used in such applications with UX:3 chip technology and ceramic conversion technology which is standard practice for white headlight LEDs,” says Stefan Grtsch, senior key expert at Osram Opto. Even the special mounting technology based on the Osram Ostar platform was transferred from projection to this automotive application, involving soldering the chip directly to the copper. The large amounts of heat produced as a result of the high output can be dissipated much more easily, which in turn greatly improves the thermal connection, says the firm.
Path to series production
The high brightness values were measured in the laboratory but they should be achieved soon also by series-production LEDs, reckons Osram Opto. The results of R&D will gradually flow into product development next year, adds the firm.
Together with the use of laser technology which produces very high luminance, a series LED could lead to extremely compact headlight solutions, says Osram, expanding its product portfolio in this sector. It is conceivable, for example, that headlights will become ultra-compact, comprising a laser high beam and LED low beam, and that other automotive applications such as interior lighting and new types of head-up display will follow. These displays will project key information directly onto the windshield, such as video of the area directly in front of the car or navigation instructions, and will be much more vivid and graphic than is the case with existing systems, says Osram. They will therefore be classed as ‘augmented reality’ displays because they enrich the viewing experience with additional information.
