Thermal mangement article having thermal wave guide

An article includes a stack of display layers including a display layer having a high-shear modulus that is sandwiched between two display layers having a low-shear modulus. The display layers include a light-emitting device that generates heat and light during use. The heat generated by the display layers may form localized heat-sources in the stack. The display layer with the high-shear modulus is a thermal transport layer through which the localized heat-sources-induced guided elastic waves propagate along an acoustic waveguide plane and can transport the heat generated by the light-emitting device away from the light-emitting device. Alternately, a display layer having a high refractive index may be sandwiched between two display layers having a low refractive index. The display layers with low shear modulus or low refractive index may be replaced with thermal transport layers having low shear modulus or low refractive index respectively.