A backlight unit (1, 1000) comprising: a backlight module (5, 700) comprising a printed circuit board including a plurality of blocks (110b, 510b) and a plurality of multi cell light emitting diodes disposed on the plurality of blocks (110b, 510b), the backlight untit (1, 1000) further comprising a backlight control module (2, 800) for independently controlling operation of each of the multi cell light emitting diodes, wherein each of the blocks (110b, 510b) comprises at least one multi cell light emitting diode, wherein the backlight control module (2, 800) comprises a drive controller (4, 820) for On/Off control and dimming control of each of the multi cell light emitting diodes, and wherein each of the multi cell light emitting diodes comprises: a plurality of light emitting diode cells including a first light emitting diode cell and a second light emitting diode cell, the plurality of light emitting diode cells being disposed on a single growth substrate separated from each other and being electrically connected to each other in series, each of the light emitting diode cells comprising: a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer, and an active layer disposed between the upper and lower semiconductor layers; a reflective lower electrode disposed on the first light emitting diode cell and electrically connected to the first light emitting diode cell; an upper electrode electrically connecting the first light emitting diode cell to the second light emitting diode cell; a first insulation layer insulating the upper electrode from a side surface of the first light emitting diode cell; a first pad disposed above the upper electrode; and a second pad, wherein the first pad is electrically connected to an input light emitting diode cell and the second pad is electrically connected to an output light emitting diode cell. a printed circuit board including a plurality of blocks (110b, 510b) and a plurality of multi cell light emitting diodes disposed on the plurality of blocks (110b, 510b), the backlight untit (1, 1000) further comprising a backlight control module (2, 800) for independently controlling operation of each of the multi cell light emitting diodes, wherein each of the blocks (110b, 510b) comprises at least one multi cell light emitting diode, wherein the backlight control module (2, 800) comprises a drive controller (4, 820) for On/Off control and dimming control of each of the multi cell light emitting diodes, and wherein each of the multi cell light emitting diodes comprises: a plurality of light emitting diode cells including a first light emitting diode cell and a second light emitting diode cell, the plurality of light emitting diode cells being disposed on a single growth substrate separated from each other and being electrically connected to each other in series, each of the light emitting diode cells comprising: a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer, and an active layer disposed between the upper and lower semiconductor layers; a reflective lower electrode disposed on the first light emitting diode cell and electrically connected to the first light emitting diode cell; an upper electrode electrically connecting the first light emitting diode cell to the second light emitting diode cell; a first insulation layer insulating the upper electrode from a side surface of the first light emitting diode cell; a first pad disposed above the upper electrode; and a second pad, wherein the first pad is electrically connected to an input light emitting diode cell and the second pad is electrically connected to an output light emitting diode cell. a plurality of light emitting diode cells including a first light emitting diode cell and a second light emitting diode cell, the plurality of light emitting diode cells being disposed on a single growth substrate separated from each other and being electrically connected to each other in series, each of the light emitting diode cells comprising: a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer, and an active layer disposed between the upper and lower semiconductor layers; a reflective lower electrode disposed on the first light emitting diode cell and electrically connected to the first light emitting diode cell; an upper electrode electrically connecting the first light emitting diode cell to the second light emitting diode cell; a first insulation layer insulating the upper electrode from a side surface of the first light emitting diode cell; a first pad disposed above the upper electrode; and a second pad, wherein the first pad is electrically connected to an input light emitting diode cell and the second pad is electrically connected to an output light emitting diode cell.