Patent ID: 7573446
Filing Date: 2009-08-11
Classification: H05B

Abstract:
1. A driving method of an LED element including an active region having a multiquantum well structure, in which a plurality of light emitting layers emitting light having different light emitting wavelength peaks from each other upon current injection, are serially put on each other with a barrier layer being interposed, color of emitted light from which substantially depends only upon driving current value, and the color of emitted light changes with a change in the driving current value on a CIE chromaticity diagram, the method comprising: a driving current value calculation step of obtaining a value for designating a current value corresponding to a desired color of emitted light from the LED element; a driving current generation step of generating a driving current having the current value designated by the values obtained in the driving current value calculation step; and a driving current supply step of supplying the LED element with the driving current generated in the driving current generation step, said plurality of light emitting layers of the LED element being sandwiched by a pair of p-type and n-type layers, wherein a plurality of values for designating a plurality of current values corresponding to a plurality of colors of emitted light from the LED element, are obtained in the driving current value calculation step, the plurality of colors being different from each other to be mixed to make the desired color of emitting light from the LED element, and wherein a driving current including a plurality of pulses having pulse heights I different from each other, designated by the plurality of values obtained in the driving current value calculation step, is generated in the driving currrent generation step.