Patterned reflectors can improve the light-extraction efficiency of light-emitting diode ( LED) chips.Inthe investigation,a triangular lattice of the micro-scale SiO₂-cone array was placed on the backside of a sapphiresubstrate,and then the metal Al was deposited on the lattice,so that a patterned reflector was built.Three-dimensionalsimulation results obtained through the Monte Carlo ray tracing method show that,as compared with the planemirror,the SiO₂-cone patterned Al backside reflector can improve the light-extraction efficiency of LED chips by7.5%.Experimental results indicate that,when the injection current is 20mA,the LED samples with the patternedreflector achieve a light-output power increase by 8.4% without the degradation of the electrical performance,incomparison with those with plane mirrors.It is found from the two-dimensional finite-element thermodynamic simulationsthat the pattern reflector helps to achieve lower chip temperature and smaller chip thermal-stress in comparisonwith the plane mirror.In addition,the thermal stress concentration in the vicinity of micro-structures has littleeffect on the performance of LED chips.