The invention provides a light generating device (1000) comprising (i) a first series (1100) of at least two first LEDs (100), which are electrically conductively coupled, and (ii) a first support (2100) configured to support the at least two first LEDs (100), wherein: (i) the at least two first LEDs (100) comprise solid-state LEDs (10); and (ii) the at least two first LEDs (100) comprise a p-side up LED (110) and an n-side up LED (120), and wherein the at least two first LEDs (100) are configured to generate first LED light (101) having dominant wavelengths within 50 nm of each other.

The invention provides a light generating device (1000) comprising (i) a first series (1100) of at least two first LEDs (100), which are electrically conductively coupled, and (ii) a first support (2100) configured to support the at least two first LEDs (100), wherein: (i) the at least two first LEDs (100) comprise solid-state LEDs (10); and (ii) the at least two first LEDs (100) comprise a p-side up LED (110) and an n-side up LED (120), and wherein the at least two first LEDs (100) are configured to generate first LED light (101) having dominant wavelengths within 50 nm of each other.

A lighting device may include a light source, a plurality of drive circuits, and a control circuit. The light source may include a plurality of emitter circuits that are configured to emit light. The light source may include a first emitter circuit that is configured to emit light at a first color (e.g., color temperature), a second emitter circuit is configured to emit light at a second color (e.g., color temperature), and a third emitter circuit is configured to emit light at a third color (e.g., color temperature). The first, second, and third colors (e.g., color temperatures) may be on a color curve, such as a color temperature curve like the black body locus. The control circuit may be configured to control the amount of power delivered to no more than two emitter circuits to emit light when controlling the light emitted by the light source to the target intensity.

Apparatus and methods for controlling correlated color temperature (CCT) and lighting intensity in lighting fixtures are described. The CCT and intensity may be controlled independently over conventional AC wiring using a conventional dimmer. A lighting controller that resembles a conventional dimmer and that can be installed in place of a dimmer may be used instead of a conventional dimmer to access more control functionalities, still using conventional AC wiring. Wireless communication with the lighting fixture and/or lighting controller are possible.

An LED light bulb comprising a lamp housing, a bulb base, connected to the lamp housing, a stem connected to the bulb base and located in the lamp housing; an LED filament, disposed in the lamp housing, where points of the LED filament in an xyz coordinates are defined as x, y, and z, an x-y plane of the xyz coordinates is perpendicular to the height direction of the LED light bulb, an z-axis of xyz coordinates is parallel with the stem, and the projection of the LED filament on the x-y plane, y-z plane and x-z plane respectively has a length L1, L2 and L3, and the length L1, the length L2, and the length L3 are substantially in a ratio of 1:(0.5 to 1):(0.6 to 0.9).

A LED lighting system, such as a dimmable LED lamp, that may simulate the performance of an incandescent bulb. LED strings of different colors may be connected to the output of a single LED driver that regulates an overall intensity of light produced by the LED lighting system. The color of the LED lighting system may be controlled by circuitry, such as one or more switches, that allocates current between the LED strings to change the color temperature of light emitted by the LED lighting system as the light intensity changes.

Apparatus and methods for controlling correlated color temperature (CCT) and lighting intensity in lighting fixtures are described. The CCT and intensity may be controlled independently over conventional AC wiring using a conventional dimmer. A lighting controller that resembles a conventional dimmer and that can be installed in place of a dimmer may be used instead of a conventional dimmer to access more control functionalities, still using conventional AC wiring. Wireless communication with the lighting fixture and/or lighting controller are possible.

A control circuit for a light emitting diode (LED) lighting system for achieving a dim-to-warm effect is provided. The control circuit includes an LED controller, a clamp circuit coupled to a set of warm correlated-color-temperature (“CCT”) LEDs, a switch coupled to a set of cool LEDs, and a feedback circuit coupled to the clamp and the switch. The LED controller is configured to control the clamp circuit to clamp current through the set of warm LEDs based on the input current, and control the switch to switch on the set of cool LEDs responsive to the input current being greater than a first threshold level and to switch off the set of cool LEDs responsive to the input current being lower than the first threshold level. The feedback circuit is configured to divert current from the set of warm LEDs to the set of cool LEDs.

The invention provides a lighting device (100) configured to provide lighting device light (101). The lighting device (100) comprises a plurality of light sources (200) configured to provide light source light (201), the plurality of light sources (200) comprising at least a first light source (210) configured to generate first light source light (211) and a second light source (220) configured to generate second light source light (221). The lighting device further comprises a light guide (300) comprising: a luminescent material (310) excitable by the light source light (201), and configured to provide luminescent material light (311), wherein the luminescent material (310) is configured to reabsorb at least part of its luminescent material light (311), a light exit window (330) for escape of the luminescent material light (311) from the light guide (300), and a plurality of light incoupling areas (320) arranged perpendicular to the light exit window (330) and comprising at least a first light incoupling area (321) configured at a first distance (d1) from the light exit window (330), and a second light incoupling area (322) configured at a second distance (d2) from the light exit window (330). The first light source (210) is configured to provide said first light source light (211) to the first light incoupling area (321), wherein the second light source (220) is configured to provide said second light source light (221) to the second light incoupling area (322), wherein the first distance (d1) is unequal to the second distance (d2). The lighting device further comprises a control unit (500) arranged for controlling the color temperature of the lighting device light by independently controlling the plurality (m) of light sources (200) dependent on the distance of each light source from the light exit window (330).

An high-efficiency light bulb, comprising: a lamp housing with inner surface and outer surface opposite to the inner surface of the lamp housing, the lamp housing includes a layer of luminescent material, which is formed on the inner surface or the outer surface of the lamp housing or integrated in the material of the lamp housing; a bulb base connected to the lamp housing; a stem connected to the bulb base and located in the lamp housing; and a single filament, disposed in the light housing, further comprising a plurality of supporting arms, connected with and supporting the LED filament, wherein the stem comprises a stand extending to the center of the lamp housing, the stand supports the supporting arms.