Abstract: A light source and a method for operating the same are disclosed. The light source includes a light emitter and a controller. The light emitter generates light in response to a control signal coupled thereto. The light emitter is characterized by an age related to the amount of light that has been cumulatively generated by the light emitter, the generated light for a given control signal changing with the age. The controller measures the age of the light emitter and generates the control signal based on the desired light intensity and the measured age of the light emitter. In one embodiment, the controller stores an age value for the light emitter, and the controller determines the control signal in response to an input signal specifying a desired light intensity from the light emitter, the controller updating the age value each time the control signal is determined.

Abstract: A lighting apparatus is described. One embodiment of the lighting apparatus includes a substrate and a lighting element. The lighting element is coupled to the substrate to emit light through a light exit plane. The light exit plane is substantially perpendicular to the substrate. By providing a lighting device with a substrate oriented perpendicular to the light exit plane of the lighting device, the lighting device can enable better mixing of the light from different LEDs. The lighting apparatus facilitates light mixing, generally, to minimize or eliminate dark spots on the diffusion panel. The lighting device also facilitates color mixing to produce relatively consistent white light on the diffusion panel.

Abstract: A lighting apparatus is described. One embodiment of the lighting apparatus includes a substrate and a lighting element. The lighting element is coupled to the substrate to emit light through a light exit plane. The light exit plane is substantially perpendicular to the substrate. By providing a lighting device with a substrate oriented perpendicular to the light exit plane of the lighting device, the lighting device can enable better mixing of the light from different LEDs. The lighting apparatus facilitates light mixing, generally, to minimize or eliminate dark spots on the diffusion panel. The lighting device also facilitates color mixing to produce relatively consistent white light on the diffusion panel.

Abstract: A lighting system is described. One embodiment of the lighting system includes a light guide, a first lighting device, and a second lighting device. The light guide receives light along a transmission interface. The first lighting device has a first plurality of lighting elements coupled to a first substrate between a first pair of reflector walls. The first substrate and the first pair of reflector walls define a first exposed side of the first lighting device. The second lighting device has a second plurality of lighting elements coupled to a second substrate between a second pair of reflector walls. The second substrate and the second pair of reflector walls define a second exposed side of the second lighting device configured to match the first exposed side of the first lighting device. Using lighting devices without sidewalls illuminates a diffusion panel so that there are no dark spots.

Abstract: A light source is disclosed. The light source has a light-emitting chip that includes an LED that generates light in an active region thereof. The LED emits a light signal in a forward direction, and infrared radiation generated in the active region is emitted in a side direction in the form of a first infrared signal. The first light signal is determined by a first drive signal coupled to the LED. The light source also includes an infrared detector positioned to collect a portion of the infrared signal. The infrared detector generates a heat signal indicative of the amount of infrared radiation detected. A controller generates the drive signal so as to maintain the heat signal at a first target value. In light sources having LEDs that emit in different spectral ranges, the infrared detectors can all detect heat in the same spectral range.