The directionality of LED lighting is limited in that the beam angle of
LED spots is wider than that of halogen spots. In order to be able to better evaluate and compare lighting solutions with spot radiation of LED lamps, the company Cree proposed the Optical Control Factor (OCF), a characteristic value with which the directional beam characteristic of LED lamps can be measured. The OCF factor results from the quotient of the luminous fl ux(lumen) to the scaled area in square millimetres. The scaled area is the light-emitting area of the light-emitting diode. Thus, the OCF factor increases as the luminous flux increases or as the scaled area decreases. For LED arrays, the scaled area increases with the number of LEDs.