Patent ID: 7078856

Claim:
A wavelength variable light source comprising: a light emitting layer containing therein light emitting substance having a carbon-carbon inter-atomic bond; a pair of electrodes, one electrode of the pair of electrodes is disposed on each side of the light emitting layer so as to hold the light emitting layer therebetween; a pair of main reflectors disposed on both sides of the light emitting layer so as to hold the light emitting layer therebetween, thereby to constitute an optical resonator with respect to light emitted from the light emitting layer; and refractive index modulating means disposed on the optical path of the optical resonator, the refractive index modulating means being capable of reversibly varying the length of the optical path of the optical resonator so as to control the wavelength of the light emitted from the light source, wherein an auxiliary electrode having light transmittance is disposed outside of at least either one of the pair of electrodes holding the light emitting layer therebetween.