A width W5 of the first protrusion 220a or the second protrusion 220b of the second electrode unit 220 in the first axis (X) direction may be about 3/10 to about 4/10 of the width W10 of the first side of the substrate 201 in the first axis (X) direction. Since the insulating reflection layer 230 may include the first recess 230a and the second recess 230b, the second electrode unit 220 may include the first protrusion 220a or the second protrusion 220b. An area of the first protrusion 220a or the second protrusion 220b of the second electrode unit 220 may be equal to or less than that of the first recess 230a or the second recess 230b of the insulating reflection layer 230.