Osram LED: Longer lifetime at high temperatures


Osram Oslon Square

Excessive heat generation is one of the main reasons why light-emitting diodes fail. With the Oslon Square, Osram Opto Semiconductors presents an LED that withstands high ambient temperatures particularly well. To ensure that the colors of several LEDs in a luminaire remain uniform even at higher temperatures, they are measured and binned at 85 degrees Celsius (°C), a temperature that comes very close to that encountered in lighting applications within buildings, in everything from spotlights to retrofit light sources.

Osram has optimized the heat dissipation of the Oslon Square to allow an increase in the junction temperature. “With our new conversion technology, we can produce significantly thinner converter layers. The thinner layers better dissipate the heat, thus enabling the higher temperatures in the LED,” says Ivar Tangring, SSL Product Development at Osram Opto Semiconductors, explaining the advantages of the innovative technology. With that, the Oslon Square can reach a lifetime of considerably more than 50,000 hours even at high temperatures of up to 135° C in the LED.

Customers benefit from the properties of the new Oslon Square

Measuring and binning at operating temperatures of 85° C is of great significance to customers who further process the light-emitting diodes into luminaires. They receive precise information on parameters such as luminous flux or color stability, which they need to optimally define the properties of their products.

Furthermore, the improved temperature behavior leads to higher luminous efficacy in the application. “This luminous efficacy, meaning the ratio of luminous flux to applied electrical power, helps our customers to significantly optimize the price/performance ratio of their luminaire solutions,” Tangring emphasizes. Thanks to the higher permitted junction temperatures, fewer large heat sinks are required, and this simplifies the design of lamps and luminaires, because they can be smaller and therefore less costly.

Application in interior lighting

The Oslon Square is particularly suitable for the various applications in buildings. With a color temperature ranging between 2,400 and 5,000 Kelvin, it can generate either warm- or cold-white light. The color rendering index is over 80 and the luminous flux is an impressive 202 lumens (lm). Product variations with a different color temperature spectrum and higher color rendering indices are to follow.

At present, the new LED is undergoing extensive quality testing: The certification process under the LM-80 long lifetime standard is underway. The results of the 3,000 hour test are expected at the end of the year, those of the 6,000 hour test in spring 2014.

Technical data (GW CSSR M1.EC) – All data at a junction temperature of 85 °C:

Housing dimensions 3 mm x 3 mm
Beam angle 120 °
Typical voltage (at 700 mA) 2.9 V – max. 3.2 V
Current max. 1.8 A (previously 1.5 A)
Typical brightness (at 700 mA) ~ 202 lm (at 3,000 K)
Color rendering index (CRI) min. 80
Thermal resistance Rth 3 K/W (previously 3.8 K/W)
Color temperature 2,400 – 5,000 K


OSRAM, with its headquarters in Munich, is one of the two leading lighting manufacturers in the world. Its subsidiary, OSRAM Opto Semiconductors GmbH in Regensburg (Germany), offers its customers solutions based on semiconductor technology for lighting, sensor and visualization applications. Osram Opto Semiconductors has production sites in Regensburg (Germany) and Penang (Malaysia). Its headquarters for North America is in Sunnyvale (USA). Its headquarters for the Asia region is in Hong Kong. Osram Opto Semiconductors also has sales offices throughout the world. For more information go to www.osram-os.com.