LED illumination apparatus with heat sink having a portion of heat fins exposed to axial forced flow from a cooling fan

1. An LED illumination apparatus comprising:

an LED substrate;

an LED package mounted on the LED substrate;

a base having a first surface, a second surface opposite the first surface, and a concave part formed on the first surface for receiving the LED substrate;

a heat sink including

a rectangular flat plate having a main surface thermally connected to the second surface of the base, and a heat radiation surface opposite the main surface, and

a plurality of first heat radiation fins having a rib-shape and protruding from the heat radiation surface of the flat plate, the first heat radiation fins extending from a periphery of the flat plate at two opposing sides;

a cooling fan; and

a casing housing the LED substrate, the base, the heat sink, and the cooling fan, wherein

the base is shaped such that a part of each first heat radiation fin extending from the periphery of the flat plate is exposed from the first surface of the base,

the cooling fan takes in air from a side of the casing that the LED package emits light and through the first heat radiation fins, and

the LED substrate has a through hole so as to allow air in an illumination part to contact the base.

2. The LED illumination apparatus according to claim 1 , wherein

a diameter of the cooling fan is substantially equal to a length of the first heat radiation fins in a traverse direction.

3. The LED illumination apparatus according to claim 1 , wherein the heat sink further includes a plurality of second heat radiation fins protruding from the heat radiation surface of the flat plate by substantially a same size as those of the first heat radiation fins and from the periphery of the flat plate at a side other than the two opposing sides thereof, and

the base is further shaped such that the second heat radiation fins are exposed from the first surface of the base.