Patent ID: 8395312

Claim:
A light source comprising: a first LED that emits light at a first wavelength; a layer of phosphor that is illuminated by said first LED, said phosphor being excited by light of said first wavelength to convert light of said first wavelength to a band of wavelengths having wavelengths greater than said first wavelength and having a dominant wavelength less than 555 nm; and a second LED that emits light at a third wavelength that is greater than said first wavelength, wherein said phosphor is not substantially excited by light of said third wavelength, and wherein said combined light from said phosphor, and first and second LEDs is perceived as being white by a human observer; and wherein said second LED has a higher efficiency for converting electrical energy into light at said third wavelength than the efficiency characterizing the combination of said first LED and said phosphor for converting electrical energy into light at said third wavelength.