Converted red LED cuts temperature droop for car rear lights
It has moved to phosphor conversion, rather than native red emission, to beat temperature droop.
The part is called Synios P2720 CR – the initials for ‘converted red’.
“One of the main issues with monochromatic LEDs for rear fog applications is the loss of brightness of about 50% in operating temperatures of 60°-70°C,” according to the company. “Until now, rear lamp manufacturers had to compensate for this physically induced gap by increasing the number of LEDs, which also increased space requirements.”
Instead, it is claiming only around 10% loss of brightness – see graph left: “Manufacturers benefit because fewer individual LEDs are required. Fewer LEDs means the required heat sink can be compact, saving space and weight.
There is a choice of two chip sizes: 0.5mm2 or 1mm2. Both come in 2.0 x 2.7 x 0.6mm packages.
The die behind the red conversion phosphor is blue, with a typical wavelength range of 442nm – 450nm. Less that <5% of that blue gets into the output spectrum – see graph right
The larger die version is intended to be driven at 700mA, where luminus flux bins are available across 90 to 125 lm (31.4 to 39.1cd luminous intensity), and voltage bins span 2.75 to 3.5V.
Colour coordinates are Cx = 0.64, Cy = 0.34 to CIE 1931.
As befits a part for vehicles, it is AEC-Q102 qualified with RV-level 1 and 8kV electrostatic discharge according to ANSI/ESDA/JEDEC JS-001 (HBM, Class 3B). Corrosion robustness is Class: 3B.