Osram has started hot binning the Oslon Square which reportedly withstands high ambient temperatures particularly well. Osram notes that 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. For this reason, Osram contends that measuring and binning at operating temperatures of 85° C is of great significance to customers who further process the light-emitting diodes into luminaires. According to Osram, its OEM customers receive precise information on parameters such as luminous flux or color stability, which they need to optimally define the properties of their products. Osram says it 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. Osram claims that with this heat dissipating structure, 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.
In addition to longer life, Osram says that 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. Also, thanks to the higher permitted junction temperatures, fewer large heat sinks are required, the company pointed out
The Oslon Square comes in a color temperature ranging between 2,400 (warm white) and 5,000 Kelvin (cool white). The color rendering index of the LED is over 80 and the luminous flux is an impressive 202 lumens (lm) at 3000K operating at 700mA. This translates to about 100 lm/W at 2.9 V. Currently, Osram says that the new LED is undergoing extensive quality testing including the certification process under the LM-80 long lifetime standard. 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.
LED hot binning
As the name implies, hot binning is binning the LED lamps at a higher temperature than the conventional 25°C. The LED manufacturers who have decided to launch new products binned at an elevated temperature have converged on 85°C as the new conventional binning temperature. Though 85°C, like 25°C before it, is somewhat arbitrary, it has one major advantage it is a lot closer to the typical operating temperature of many solid-state lighting luminaires than 25°C.
Binning at 85°C makes the initial part of the design process slightly easier and more intuitive. For example, if a designer were working on an LED system that needed 1,000 lumens at an 85°C temperature, then he or she could simply select 10 LED lamps with a luminous flux of 100 lumens per LED, binned at 85°C. Thus, hot binning makes it easy to estimate the performance of these LED lamps in this real-world situation. On the other hand, if the LEDs were binned at 25°C, the same 10 LED lamps would need to be binned at 114 lumens each and de-rated per the LEDs mathematical framework (Fig. 3) to arrive at the same 1,000 lumen goal at the system level.
So, the good news is binning at 85°C makes the first-pass math more intuitive. The bad news is you still have to do the same math if your system runs or ever runs at any temperature other than 85°C. Examples of this would be outdoor luminaires (60° to 65°C is much more common) or freezer cases (20° to 25°C is typical) or downlights in insulated ceilings or almost any retrofit bulb (often over 100°C). In each of these cases the value of binning at 85°C is lost and the designer is back to doing the same math from a new mathematical framework where, arbitrarily, 85°C is now set to equal 100%.
OSLON Square LED
- Different luminous flux packages from one package family
- High luminous efficacy at high currents
- Superior corrosion robustness
- Binned at 85 °C
- 135 °C Tj max., 1.8 A If max.
- Package: SMT ceramic package with silicone resin and silicone lens
- Full CCT range available: 2400 K – 5000 K (warm and neutral white)
- CRI: min. 80 (typ. 82)
- Viewing angle at 50 % IV: 120°
- Luminous Flux: typ. 202 lm @ 3000 K, 85 °C
- Luminous efficacy: typ. 100 lm/W @ 3000 K, 85 °C
- Lumen Maintenance: Test results according to IESNA LM-80 available