Del Mar Photonics

Simple explanation of confocal microscopy by Andrew Resnick (Case Western)

"Confocal" simply means that the source, object, and image all share the same focal plane.  Depth sectioning from "confocal microscopy" results from using a pinhole for the detector as well as the source- the pinholes are confocal to each other.  The spinning disk uses the same set of pinholes for source and detector, so they are confocal by construction.

Use of different light sources does not really relate to confocal microscopy, except for considerations of brightness and color selection- the pinhole is the source, as far as the microscope is concerned.

Other than Pawley's excellent book, I also use "Confocal Microscopy" edited by T. Wilson and :Confocal Scanning Optical Microscopy and Related Imaging Systems" by Corle and Kino.

Confocal and Two-Photon Microscopy: Foundations, Applications and Advances, Alberto Diaspro
Handbook of Biological Confocal Microscopy, James Pawley
Douglas B Murphy, Fundamentals of Light Microscopy and Electronic Imaging (Wiley-Liss).
Alan Hibbs: Confocal Microscopy for Biologists (Springer)