A light emitting device includes a substrate having a top surface, upper and lower metal layers, multiple LED chips, at least one Zener diode, multiple conductive wires and an encapsulant. The top surface includes a central region bounded by an imaginary boundary with a profile conforming to an outline of a circle stacked with a polygon. The central region has a die bonding area corresponding to the circle, and at least one polygonal extension area formed outside the die bonding area. The upper metal layer includes multiple conducting pads surrounding the central region. The LED chips are disposed on the die bonding area. The Zener diode is disposed on the polygonal extension area. The encapsulant is disposed on the substrate and covers the LED chips.