In a lighting apparatus, comprising a heatsink having at one side thereof a recess with at least one groove extending over the length of the heatsink, a plurality of lighting units are arranged in the groove or grooves oriented toward the opening of the recess for the emission of light therefrom and the frame is provided at the side opposite the opening with heatsink ribs, the lighting units in the groove or grooves being encapsulated by an encapsulating material added into the groove or grooves and being cured therein so as to be in direct contact with the groove walls and enclosing the lighting units at least up to the light emitting lenses thereof.