generated for different target luminance of the light source the shortcoming that luminance may be regulated to a set extent only in the related technology is overcome the luminance of the light source may be smoothly regulated and dimming flexibility is ensured those skilled in the art should know that the embodiment of the disclosure may be provided as a method a system or a computer program product therefore the disclosure may adopt a form of pure hardware embodiment pure software embodiment and combined software and hardware embodiment moreover the disclosure may adopt a form of computer program product implemented on one or more computer available storage media including but not limited to a disk memory an optical memory and the like including computer available program codes the disclosure is described with reference to flowcharts and or block diagrams of the method equipment system and computer program product according to the embodiment of the disclosure it should be understood that each flow and or block in the flowcharts and or the block diagrams and combinations of the flows and or blocks in the flowcharts and or the block diagrams may be implemented by computer program instructions these computer program instructions may be provided for a universal computer a dedicated computer an embedded processor or a processor of other programmable data processing equipment to generate a machine so that a device for realizing a function specified in one flow or more flows in the flowcharts and or one.