Talk:Centre wavelength

Definition
The current definition is wrong. It is rather the definition of the centroid wavelength. This may caused by using Symbol λc instead of λ0.5m.

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.

λ0.5m= (λ'0.5m+ λ"0.5m) / 2

To avoid confusion it would be helpful to have reference to the following definitions as well:

λc Centroid Wavelength

λ0.5m Center Wavelength

λp 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)