A colleague was kind enough to arrange for a machine translation of the Japanese patent publication.
I have not yet perused it at any length. The translation is a bit clumsy but is still very welcome.
The patent indeed refers to a flash unit using (for example) three sets of LED's so that the chromaticity of the flash burst can be set, presumably (as mentioned by one of the correspondents here) so that the flash illumination can match the chromaticity of the ambient illumination. [Note that this involves more than the correlated color temperature, although much of the discussion proceeds as if that is the only parameter of interest.].
Presumably this concept itself has been covered in earlier patents.
The thrust of this patent (as it seemed from the earlier characterization) is to provide for automatic flash exposure control to perform properly in this situation.
The basic idea ("matchable" flash burst chromaticity) sounds very worthwhile.