Patent ID: 9055644
Filing Date: 2015-06-09
Classification: F21V,F21W,F21Y,H05B,H05K,Y02B

Abstract:
1. A lighting apparatus for use with a plurality of light emitting diodes comprising: a power source arranged to supply the plurality of light emitting diodes with electric power for illumination; a first controller arranged to change the number of the light emitting diodes which are supplied with electric power for illumination by the power source, and to determine a maximum limit of electric power to be supplied to each of the light emitting diodes in dependence on the number of the light emitting diodes which are supplied with electric power for illumination; and a second controller arranged to change the electric power to be actually supplied to each of the light emitting diodes the number of which is changed by the first controller, the second controller controlling the electric power independently from the first controller but within the maximum limit determined by the first controller to optionally change a luminance attained by the light emitting diodes to any desired luminance within the maximum limit; and a heat radiator having a heat radiating capacity, the heat radiator being arranged for use in common by the plurality of light emitting diodes, wherein the first controller is arranged to determine the maximum limit of power to be supplied to each of the light emitting diodes so that a total heat generated by the light emitting diodes which are supplied with electric power for illumination by the control of the second controller does not exceed the heat radiating capacity of the heat radiator, and wherein the first controller is arranged to decrease the maximum limit of power to be supplied to each of the light emitting diodes if the number of the light emitting diodes which are supplied with electric power for illumination is increased and to increase the maximum limit of power to be supplied to each of the light emitting diodes if the number of the light emitting diodes which are supplied with electric power for illumination is decreased.