| photobiologyLEDs-package {photobiologyLEDs} | R Documentation |
photobiologyLEDs: Spectral Data for Light-Emitting-Diodes
Description
Spectral emission data for some frequently used light emitting diodes available as electronic components. Part of the 'r4photobiology' suite, Aphalo P. J. (2015) doi:10.19232/uv4pb.2015.1.14.
Details
Data for emission spectra of different types of LEDs and LED arrays.
The package contains one main collection of spectra for different LEDs
available as electronic components through hole (th), surface mount devices
(SMD) and chip-on-board (COB) packages with no built-in driver circuitry to
limit the current, leds.mspct. Data for LED bulbs and LED
luminaires/lamps are included in package
photobiologyLamps-package. Two smaller
collections, provide spectra for a COB LED driven with varying current or
constant-current (CC) dimming, COB_dimming.mspct, and at fixed
current but in combination with different reflectors,
COB_reflectors.mspct.
In addition to the spectra the package provides character vectors of names to
be used as indexes to subset groups of spectra from leds.mspct. In all
cases spectral data are normalized to spectral energy irradiance equal to one
at the wavelength of maximum spectral energy irradiance (strongest emission
peak). In most cases the multiplier used for normalization can be obtained by
quering the object. However, this is useful only in those cases where the
distance from source to entrance optics of the spectrometer and alignment
were recorded.
All LEDs have been measured at room temperature mounted on passive heatsinks and usually driven near their maximum current rating. Precision power supplies or LED drivers were used to drive them at constant current.
The number of different LED types available is enormous, and this collection attempts only to provide examples for some of them. Which types are included is the result of what has been bought for specific uses at my lab or out of curiosity since 1995 to the present. Which brands and LED types are included, should not be interpreted as endorsement of any supplier.
Warning!
None of the spectral data included in this package are based on supplier's specifications and are only for information. The exact emission spectrum of a LED depends to some extent on testing conditions, but more importantly among individual LED dies. Spectral specifications are usually given by typical and boundary values. Furthermore, most manufacturers classify LEDs of a given type into "bins" with slightly different colour and electrical characteristics. In addition, the performance of LEDs deteriorates with use, with light output decreasing faster if driven with high current or if they overheat as a consequence of insufficient cooling. In other words, the data provided here are not a substitute for actual measurements of radiation emission and spectrum of the LEDs actually used in a given piece of scientific research or other important work. For less demanding situations, such as planning of experiments or testing the sanity of independent measurements, the data are in most cases reliable enough but perfect agreement with measurements on other LEDs of the same exact type should not be expected.
Note
Some of the LEDs were bought from AliExpress sellers while others were sourced from major electronic component distributors like Farnell, RS components, Digi-Key, Mouser, TME, Roithner-Lasertechnik, and Lumitronix/LedRise. In the case of some AliExpress sellers or smaller webstores sometimes the exact type specifications are not available. Some of the Chinese sellers package the LEDs they sell using LED dies (= chips) from major brands and provide this brand name. In very recent times this seems to have expanded in some cases to include high density COB packages. Be aware that in recent times the word COB is being used by AliExpress, Bangood and eBay sellers to describe old-style arrays where the LED chips are not directly attached to a board to maximize thermal conductance. In this package, we use COB in its more restricted meaning and name other packages simply LED array.
Author(s)
Maintainer: Pedro J. Aphalo pedro.aphalo@helsinki.fi (ORCID)
Other contributors:
Shafiuddin Ahmed [contributor]
References
Aphalo, Pedro J. (2015) The r4photobiology suite. UV4Plants Bulletin, 2015:1, 21-29. doi:10.19232/uv4pb.2015.1.14.
See Also
Useful links:
Report bugs at https://github.com/aphalo/photobiologyLEDs/issues
Examples
library(photobiology)
names(leds.mspct)
led_brands
white_leds
qe_ratio(leds.mspct$Nichia_NS6L183AT_H1_sw) * 1e6 # umol / J
is_normalized(leds.mspct$Nichia_NS6L183AT_H1_sw)
cat(comment(leds.mspct$Nichia_NS6L183AT_H1_sw))
when_measured(leds.mspct$Nichia_NS6L183AT_H1_sw)
how_measured(leds.mspct$Nichia_NS6L183AT_H1_sw)