An apparatus for monitoring a signal transmitter for a traffic control signal installation. The signal transmitter has a light-emitting diode. The monitoring apparatus includes: a two-channel measuring device for measuring an actual light intensity of the light which is emitted by the diode and for measuring at least one electrical characteristic variable of the diode, and a control device for operating the signal transmitter depending on the measured actual light intensity and the measured electrical characteristic variable. There is also described a corresponding method, a signal transmitter, a traffic control signal installation and a computer program.

A solid state lighting system includes a number of light sources with multiple light colors that can be used to replace fluorescent lamps.

A lighting device with a drive device for dimming light-emitting diodes. The drive device comprises a dimming component that operates a switch in response to both a change in an input power signal and a system temperature. In one example, the dimming device can include a waveform generator that generates a signal with a waveform having levels that change in response to changes in temperature. The waveform defines the time during which the switch is open and closed, thereby determining the period of time the LEDs are energized. By operating the LEDs in this manner, the drive device effectively dims the LEDs to reduce the operating temperature and cool the LEDs.

A LAM/ICM assembly comprises an integrated control module (ICM) and an LED array member (LAM). The ICM includes interconnect through which power from outside the assembly is received. In a first novel aspect, active circuitry is embedded in the ICM. In one example, the circuitry monitors LED operation, controls and supplies power to the LEDs, and communicates information into and out of the assembly. In a second novel aspect, a lighting system comprises an AC-to-DC converter and a LAM/ICM assembly. The AC-to-DC converter outputs a substantially constant current or voltage. The magnitude of the current or voltage is adjusted by a signal output from the LAM/ICM. In a third novel aspect, the ICM includes a built-in switching DC-to-DC converter. An AC-to-DC power supply supplies a roughly regulated supply voltage. The switching converter within the LAM/ICM receives the roughly regulated voltage and supplies a regulated LED drive current to its LEDs.

A lighting system includes at least one LED and at least one regulator in communication with the at least one LED. The at least one regulator is configured to supply a substantially constant current to the at least one LED while allowing a light output from the at least one LED to degrade over time towards a target minimum light output, and once the light output of the at least one LED is below the target minimum light output, increase current to the at least one LED to maintain the light output at the target minimum light output.

The invention describes a method of controlling a segmented flash (10) having a plurality of flash segments (S1, S2, . . . , Sn), which method comprises the steps of measuring the forward voltages (Vf1, Vf2, . . . , Vfn) of the flash segments (S1, S2, . . . , Sn); and adjusting the brightness of the flash segments (S1, S2, . . . , Sn) on the basis of the measured forward voltages (Vf1, Vf2, . . . , Vfn) to achieve a desired illumination profile (P) for the segmented flash (10). The invention further describes a segmented flash system (1) comprising a segmented flash (10) with a plurality of flash segments (S1, S2, . . . , Sn), wherein each flash segment (S1, S2, . . . , Sn) is arranged to illuminate a portion (20) of a scene (2); and a flash driver (11) adapted to perform the steps of the inventive method to adjust the brightness of the flash segments (S1, S2, . . . , Sn).

The invention describes a method of controlling a segmented flash (10) having a plurality of flash segments (S1, S2, . . . , Sn), which method comprises the steps of measuring the forward voltages (Vf1, Vf2, . . . , Vfn) of the flash segments (S1, S2, . . . , Sn); and adjusting the brightness of the flash segments (S1, S2, . . . , Sn) on the basis of the measured forward voltages (Vf1, Vf2, . . . , Vfn) to achieve a desired illumination profile (P) for the segmented flash (10). The invention further describes a segmented flash system (1) comprising a segmented flash (10) with a plurality of flash segments (S1, S2, . . . , Sn), wherein each flash segment (S1, S2, . . . , Sn) is arranged to illuminate a portion (20) of a scene (2); and a flash driver (11) adapted to perform the steps of the inventive method to adjust the brightness of the flash segments (S1, S2, . . . , Sn).

A lighting device with improved optical performance and efficiency is provided. The lighting device includes a source of energy, a light source, a reflector and a holder. The reflector has a first open end, a second end, and a parabolic profile extending between the first open end and second end. The focus of the parabolic profile is located outside of the profile. The reflector may also be movable relative to the light source. The lighting device may include a circuit that delivers a pulsed or thermally compensated pulsed current to the light source. The light device may also include a heat sink housing.

Provided is an LED retrofit lamp interfacing with a high intensity discharge (HID) ballast that includes a lighting source having a plurality of light emitting diodes (LEDs), one or more heat sink components dissipating heat generated by the LEDs, and an LED driver configured to operate the LEDs. The LED retrofit lamp is disposed within an HID housing and the HID ballast is electrically connected with the LED driver, and supplies power to the LED driver for operating the LEDs.

A lighting circuit which supplies current to a solid-state light-emitting element module (LED module) including: a solid-state light-emitting element (LED); a first connection terminal connected to one end of solid-state light-emitting element; a third connection terminal connected to another end of the solid-state light-emitting element; and a second connection terminal, includes: a characteristics detector that detects one of open and short circuits between the third connection terminal and the second connection terminal; and a power controller that adjusts current that is supplied between the first connection terminal and the third connection terminal of the solid-state light-emitting element module, to a predetermined value greater than zero, when the characteristics detector detects one of the open and short circuits between the third connection terminal and the second connection terminal.