Fight blue light emissions of white LEDs with new colour sensor

December 4, 2017 | 14:00
LEDs, and especially those that produce white light, are great for lighting applications. They consume little power in comparison to incandescent lightbulbs and it is easy to create nice colour effects with them. To produce white light a white LED often generates blue light and filters it with yellow or orange phosphor. Unfortunately, blue-light wavelengths appear to have important health effects such as disruption of the circadian rhythm, accelerated eye aging, and eye strain.

blue light contained in white led light
White LED light contains potentially harmfull blue light.

Two addtional blue light filters

The AS7264N tri-stimulus colour sensor by ams can measure blue-light wavelengths accurately, and is therefore suitable for human-centric lighting. The sensor’s on-wafer silicon interference filters create spectral channels that match the CIE 1931 XYZ standard observer model while two additional filters allow accurate measurements of blue light intensities at the 440 nm and 490 nm wavelengths.

The AS7264N provides easy-to-use digital colour measurement outputs over an I2C interface. Programmable on-chip LED drivers enable direct control of synchronized electronic shutter functionality. The sensor’s small size (4.5 mm x 4.7 mm x 2.5 mm) makes it easy to integrate it in luminaries, allowing real-time monitoring of blue light exposure of end users.

Address the interaction between light and human health

With its measurements of photobiologically active wavelengths, the sensor serves applications that address the interaction between light and human health. Ambient light characterization and light exposure data collection for commercial, residential, and industrial lighting are applications that come to mind.

Controlling the emission of blue light wavelengths at the source seems a much better solution than wearing special blue light filtering glasses or sticking yellow films on displays. White LED light may be superior for illumination in terms of colour rendering, preserving your eyes is important too. Therefore replacing all the lightbulbs in your home by LEDs is not a good idea.
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