A phosphor combination may include a first phosphor and a second phosphor. The second phosphor may be a red-emitting quantum dot phosphor. The phosphor combination may optionally include a third phosphor that is a red-emitting phosphor with the formula (MB) (TA)3-2x(TC)1+2xO4-4xN4x:E. A conversion element may include the phosphor combination. An optoelectronic device may include the phosphor combination and a radiation-emitting semiconductor chip.

A phosphor combination may include a first phosphor and a second phosphor. The second phosphor may be a red-emitting quantum dot phosphor. The phosphor combination may optionally include a third phosphor that is a red-emitting phosphor with the formula (MB) (TA)3-2x(TC)1+2xO4-4xN4x:E. A conversion element may include the phosphor combination. An optoelectronic device may include the phosphor combination and a radiation-emitting semiconductor chip.

A color temperature and brightness control system for an LED lamp of a ceiling fan includes a switch, a detection module, a determining module, a memory module, a control module, and a drive unit. The detection module detects the actuation of the switch, and the determining module performs a comparison. The control module outputs a control signal to the drive unit according to the calculation result of the determining module and the memory module to drive the lamp to actuate. The color temperature and brightness control system is able to control the lamp to be turned on/off and the brightness and color temperature of the lamp through a single switch.

A color temperature and brightness control system for an LED lamp of a ceiling fan includes a switch, a detection module, a determining module, a memory module, a control module, and a drive unit. The detection module detects the actuation of the switch, and the determining module performs a comparison. The control module outputs a control signal to the drive unit according to the calculation result of the determining module and the memory module to drive the lamp to actuate. The color temperature and brightness control system is able to control the lamp to be turned on/off and the brightness and color temperature of the lamp through a single switch.

Example adaptive vehicle headlights are disclosed. An example system includes a photodetector, an illumination source configured to generate first light during a first operating mode, a spatial light modulator (SLM), and a dichroic filter optically coupled to the illumination source and to the SLM, wherein the dichroic filter is configured to direct the first light to the SLM, and the SLM is configured to direct second light to the dichroic filter during a second operating mode, wherein the dichroic filter is configured to direct the second light having a first color to the photodetector, and direct the first light during the first operating mode.

Example adaptive vehicle headlights are disclosed. An example system includes a photodetector, an illumination source configured to generate first light during a first operating mode, a spatial light modulator (SLM), and a dichroic filter optically coupled to the illumination source and to the SLM, wherein the dichroic filter is configured to direct the first light to the SLM, and the SLM is configured to direct second light to the dichroic filter during a second operating mode, wherein the dichroic filter is configured to direct the second light having a first color to the photodetector, and direct the first light during the first operating mode.

A light-emitting circuit includes first and second light-emitting element strings respectively configured to emit light having a first and second color temperatures; a rectifying circuit configured to rectify a voltage, input by an alternating current (AC) power source, to generate a driving voltage; a string switching circuit configured to select at least one light-emitting element string to be used for light emission from among the first light-emitting element string and the second light-emitting element string; an off/on sensing circuit configured to change a selection of the string switching circuit to change a color temperature of light, which is emitted by the light-emitting circuit, when the AC power source is turned off and then turned on; and a driving circuit configured to turn on, in turn, light-emitting elements in the selected at least one light-emitting element string, according to a change in the driving voltage over time.

A light-emitting circuit includes first and second light-emitting element strings respectively configured to emit light having a first and second color temperatures; a rectifying circuit configured to rectify a voltage, input by an alternating current (AC) power source, to generate a driving voltage; a string switching circuit configured to select at least one light-emitting element string to be used for light emission from among the first light-emitting element string and the second light-emitting element string; an off/on sensing circuit configured to change a selection of the string switching circuit to change a color temperature of light, which is emitted by the light-emitting circuit, when the AC power source is turned off and then turned on; and a driving circuit configured to turn on, in turn, light-emitting elements in the selected at least one light-emitting element string, according to a change in the driving voltage over time.

A Light Emitting Diode, LED, based lighting device arranged for emitting a particular color of light, wherein said LED based lighting device comprises a power supply unit arranged for providing a Direct Current, DC, bus voltage for powering LEDs, a plurality of parallel cascaded LED channels, wherein each of said LED channels is connected to said bus voltage and comprises at least one colored LED and a switch for activating said corresponding LED channel, a controller arranged for providing control signals to each of said switches in said LED channels for periodically activating said LED channels, wherein each of said control signals has a duty cycle, and wherein said controller is arranged for determining said duty cycles of said control signals based on a received color set point, wherein said controller is further arranged for determining an amount of deficiency in light output of each of said LED channels caused by parasitic effects in said LED based lighting device, by determining instantaneous currents of each channel and comparing said instantaneous currents with expected currents resulting from the determined duty cycles, and for increasing said duty cycles based on said determined amount of deficiency.

A Light Emitting Diode, LED, based lighting device arranged for emitting a particular color of light, wherein said LED based lighting device comprises a power supply unit arranged for providing a Direct Current, DC, bus voltage for powering LEDs, a plurality of parallel cascaded LED channels, wherein each of said LED channels is connected to said bus voltage and comprises at least one colored LED and a switch for activating said corresponding LED channel, a controller arranged for providing control signals to each of said switches in said LED channels for periodically activating said LED channels, wherein each of said control signals has a duty cycle, and wherein said controller is arranged for determining said duty cycles of said control signals based on a received color set point, wherein said controller is further arranged for determining an amount of deficiency in light output of each of said LED channels caused by parasitic effects in said LED based lighting device, by determining instantaneous currents of each channel and comparing said instantaneous currents with expected currents resulting from the determined duty cycles, and for increasing said duty cycles based on said determined amount of deficiency.