The proposed method and device relate to the field of lighting technology and are intended for generating a light output indoors such as to provide uniform lighting. The housing of an elongate cornice lamp is comprised of the following components, fastened to one another: a primary plate for accommodating LED strips which generate a light output, a plate for reflecting the light output, a plate for restricting the light output, and a mounting plate. An electric power supply is disposed inside the cavity of the housing. The necessary number of LEDs is selected and these are mounted on LED strips which are fastened on the primary plates and on the plates for reflecting the light output, the LEDs are connected to the electric power supply, a set of light beams is produced, the luminous intensity of the light beams is controlled, the angles of spatial distribution of the light are modified by additional lenses, the light output is distributed with the aid of the reflecting surfaces, and the dispersion of the light output in unwanted directions is prevented with the aid of the restricting surfaces.