MICRORELIEF STRUCTURE FOR LIGHT EMITTING ELEMENT, AND LIGHT EMITTING ELEMENT AND ILLUMINATION DEVICE USING SAID MICRORELIEF STRUCTURE

摘要

Provided is a microstructure for electroluminescent (EL) elements which has superior light extraction efficiency. The microstructure for EL elements comprises a plurality of microconvexities (a) having circular bottom surfaces (p). Each microconvexity (a) has a peak (q) on a perpendicular line from the centre of the circular bottom surface (p), and is defined by a generatrix dropped from the peak (q) to the circumference of the bottom surface (p). The height of the generatrix of each convexity (a) is monotonically reduced from the peak (q) to the circumference of the bottom surface (p). The height of the peaks (q) of the convexities (a) is 0.67-1.15 times the radius of the bottom surfaces (p). The height of the convexities (a) at the position on the radius of the bottom surface (p) 3/4 away from the centre of the bottom surface (p) is 0.21-0.65 times the radius of the bottom surface (p). The height of the convexities (a) at the position on the radius of the bottom surface (p) 9/10 away from the centre of the bottom surface (p) is 0.04-0.38 times the radius of the bottom surface (p).