Talk:Centre wavelength

Definition

The current definition is wrong. It is rather the definition of the centroid wavelength. This may caused by using Symbol λ_c instead of λ_0.5m.

Correct definition of center wavelength:
The center wavelength is the wavelength halfway between the two points with a spectral density of 50% of the peak.<ref>http://spie.org/x32417.xml</ref>

λ_0.5m= (λ^'_0.5m+ λ^"_0.5m) / 2

To avoid confusion it would be helpful to have reference to the following definitions as well:
λ_c Centroid Wavelength
λ_0.5m Center Wavelength
λ_p Peak Wavelength
Central Wavelength

Further sources for definitions of Center and Centroid Wavelength:

[1] Field Guide to Illumination
A. V. Arecchi, T. Messadi, and R. J. Koshel, Field Guide to Illumination, SPIE Press, Bellingham, WA (2007)

[2] Handbook of LED Metrology
Instrument Systems, 42 Pages, 2009-09-10
http://www.instrumentsystems.com/fileadmin/editors/downloads/Products/LED_Handbook_e.pdf

[3] Symbols & Terminology
Document Number: 81252, Rev. 1.3, 18-Aug-08, VISHAY Semiconductors
http://www.vishay.com/docs/81252/symbols.pdf

[4] The Radiometry of Light Emitting Diodes
Labsphere, Inc., 18 Pages, 2001-01-03
http://www.bfioptilas.com/objects/52_23_2079453411/LED-Measurement-Guide.pdf

[5] Answers(TM)
http://www.answers.com/topic/spectral-centroid

-164.90.16.101 (talk) 21:28, 4 March 2013 (UTC)