P11543: Variable LED Hemispherical Imager
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LED Specifications

LED Specifications

Chosen LEDs

LEDs were chosen to cover as much of the visible spectrum as possible with as few gaps as possible. It was decided that a varied of LEDs would be ordered and tested to see which LEDs will cover the 400 - 650nm portion of the spectrum. Below is a list of the LEDs (and their specs) which were tested for this project:

All LEDs have a 15 degree cone angle, unless noted otherwise.

LED Testing

The full Excel file containing all of the data and results can be found here: LED Spectral Data

In order to determine the intensity and spectrum of the chosen LEDs, extensive testing was performed. The SpectraScan PR-650 spectroradiometer was used to take these measurements in the color science lab. After initial setup, 3 different LEDs of each color were analyzed. The data was collected in MATLAB and exported to a text file. This data was then analyzed and the results were plotted in Excel. The spectrum of all the LEDs can be seen below.

Spectrum of all LEDs at 255

Spectrum of all LEDs at 255

From these tests, it was determined that the 6 outer LEDs would be: Red, Orange, Yellow, Green, Blue, and White. A White LED would also be in the center. The spectrum of these LEDs is shown below.

Spectrum of LEDs in Cluster

Spectrum of LEDs in Cluster

For each color LED, the data is normalized to its maximum brightness. A plot of these normalized values for the cluster shown where the gaps exist in the spectrum.

Normalized Spectrum of LEDs in Cluster

Normalized Spectrum of LEDs in Cluster