In this application note, Ocean Insight uses a high-speed Ocean FX spectrometer to measure flicker, color and other spectral characteristics of incandescent and LED holiday lights.
During the holiday season, mesmerizing light shows and magical holiday scenery fill the world around us. Colorful, twinkling lights abound, filling the world with a festive, joyous atmosphere. It’s the perfect time for the spectroscopy of Christmas lights.
LEDs have become the holiday lighting of choice, thanks to their low power requirements, high efficiency and bright colors. Yet we can’t help but wonder how LEDs compare to incandescent holiday lights. More efficient holiday lighting may not be the first requirement on everyone’s list. Here’s what Ocean Insight discovered while characterizing the irradiance, flicker and color of multicolor LED and incandescent holiday lighting.
Experimental Setup
Ocean Insight tested strings of 20 multicolored incandescent and LED lights using an Ocean-FX-VIS-NIR spectrometer (350-1000 nm), a FOIS-1 integrating sphere, 600 µm Vis-NIR optical fiber and OceanView spectroscopy software (Figure 1). Spectral data was acquired for three bulbs of each color from each string in absolute spectral radiant flux (uW/nm) with the HL-3P-INT-CAL radiometrically calibrated light source as the reference. Using the processed mode in OceanView, Ocean Insight corrected the spectral data for the instrument response function of the Ocean FX spectrometer, with intensity reported as power in microwatts per nanometer (uW/nm).
Figure 1. Because it can acquire up to 4,500 scans per second, the Ocean FX is ideal for measuring the rapid occurrence of flicker in lighting.
Ocean Insight chose the Ocean FX because its fast electronics enabled them to measure super-bright LED holiday lights without saturating their detector. Also, the spectrometer’s high acquisition speeds allowed us to qualitatively assess flicker – a change in brightness over time typically related to fluctuations in the power source — of a blue bulb from each string of lights. Quantitative color measurements also were made for each color of the LED and incandescent light strings.