Patent ID: 8901584

Claim:
A light emitting diode comprising a compound semiconductor layer having at least a pn junction-type light emitting unit and a strain adjustment layer stacked on the light emitting unit, wherein the light emitting unit has a stacked structure comprising: (i) a plurality of strained light emitting layers having a composition formula of Ga Y In 1-Y P, wherein Y is a numerical value that satisfies 0.39≦Y≦0.45, a thickness ranging from 8 to 30 nm, and a peak emission wavelength ranging from 655 nm to 675 nm, wherein the number of the strained light emitting layers in the light emitting unit is from 8 to 40; and (ii) a plurality of barrier layers having a composition formula of (Al X Ga 1-X ) Y In 1-Y P, wherein X and Y are numerical values that satisfy 0.3≦X≦0.7 and 0.48≦Y≦0.52 respectively, wherein the individual ones of the strained light emitting layer and the barrier layer are alternatively stacked, and the strain adjustment layer is transparent to an emission wavelength, has a thickness of 3 to 15 μm, and has a lattice constant that is smaller than lattice constants of the strained light emitting layer and the barrier layer.