Think of a simple source of light, like a traditional incandescent light bulb, surrounded by a sphere. Light is given off in all directions and illuminates the inside of the sphere almost equally. With an LED, the light is directional, and is given off predominantly in one direction. If the LED points downward, imagine that the top of the sphere will be quite dark. If our working surface is below the sphere one will get almost as much light on the working surface, by starting with a light source of half the intensity of a traditional light source. This is not a fully accurate model but it does express the principle. In reality, the conventional source will probably have a reflector in an attempt to redirect some of the upward and sideways light downwards. However, the LED light may also have a lens or reflector to concentrate the light at the working surface.
One advantage of the LED light is that the side glare is significantly reduced compared to a conventional light source. Again, imagine the inside of the sphere. This is quite beneficial for cities with “Dark Sky” initiatives.
In an ALLED light fixture using reflectors, one can quite accurately direct light where it is needed.