A chip on board light emitting diode (LED) device includes a LED device, a printed circuit board (PCB) and a dissipation unit array. The LED device includes a LED substrate, a first contact pad and a second contact pad above the LED substrate and a thermal layer formed on top surface of the LED device. The thermal layer includes a thermal conductive material. A printed circuit board (PCB) includes a PCB substrate with a thermal projection extending from surface of the PCB substrate, and a first and a second electrode pads above the PCB substrate. The thermal projection and the PCB substrate include the thermal conductive material. The dissipation unit array includes a plurality of dissipation units each disposed between the LED device and the PCB. The thermal layer is thermally coupled to the thermal projection via at least one dissipation unit. Each of the first and second contact pads is electrically coupled to the corresponding electrode pad via at least one dissipation unit.