Abstract: A battery-conserving flashlight and method thereof are provided. The flashlight includes a body having a first end and a second end, the first end including an illumination source and the second end including an opening for accessing an interior of the body; at least one battery disposed in the body via the opening in the second end, the at least one battery coupled to and configured for powering the illumination source; and a controller disposed in the body configured to determine if the body is in motion, wherein if the body is not in motion for a predetermined period of time, the controller decouples the at least one battery from the illumination source to conserve energy in the at least one battery. Optionally, the flashlight may include a visual or audible indicator to alert a user that the flashlight will shutdown.

Abstract: Methods and systems for easily integrating a light-emitting diode (LED) light assembly with an existing xenon power supply. An exemplary system includes a xenon power supply that includes an energy storage device and a device that commands the energy storage device to discharge the stored energy and transmit a trigger signal after a predefined amount of time since at least one of a previous discharge or a beginning of initial charge of the energy storage device. The LED light assembly includes one or more LEDs and a current regulator that receives the discharge from the storage device and regulates current to the LEDs based on LED requirements. The LED light assembly also includes a processing device that receives the trigger signal, resets and begins a timer upon reception of the trigger signal and deactivates the current regulator when the timer has reached predefined threshold.

Abstract: The present invention relates to a lamp unit (100) in which a plurality of light sources (120a-e) are controlled by means of a control unit (110) which is adapted to control a sequence of drive settings (Sa-e) for the plurality of light sources based on a switching signal (Sin) supplied to the lamp unit. The control unit is arranged such that depending on the elapsed time between deactivation of and subsequent reactivation of the switching signal, the control unit sets the current drive settings in a predetermined manner. Within a first predetermined time interval a subsequent drive setting of the light sources is employed, after a second predetermined time interval a previous drive setting of the light sources is employed, and within an intermediate time interval, arranged between the end of the first predetermined time interval and the end of the second predetermined time interval a predetermined drive setting is employed.

Abstract: In embodiments of the present invention, a method and system is provided for designing improved intelligent, LED-based lighting systems. The LED based lighting systems may include fixtures with one or more of rotatable LED light bars, integrated sensors, onboard intelligence to receive signals from the LED light bars and control the LED light bars, and a mesh network connectivity to other fixtures.

Abstract: A light-emitting diode (LED) device for preventing soft-start flicker includes an LED module, a voltage converter, a variable current load and a loop control unit. The loop control unit is coupled to the LED module, the voltage converter and the variable current load, and includes a soft-start unit and a dimming control unit. The soft-start unit is utilized for activating a soft-start mechanism of the voltage converter when power of the LED device is turned on. The dimming control unit is utilized for controlling the variable current load to progressively increase a load current of the LED module to a target value and to maintain the load current on the target value until the soft-start mechanism is completed, so as to perform dimming control on the LED module.

Abstract: A method and a device for gradually controlling the illuminating light intensity of light-emitting diodes by modulating the width of current pulses of defined duty cycle, using a DC-to-DC voltage converter and a control circuit for switching the supply current of the light-emitting diodes. Prior to switching the power supply of the diodes the DC-to-DC converter is initiated (A), so as to generate voltage pulses of defined duty cycle; the steady state of each pulse is determined (B), so as to generate a voltage pulse (CP) calibrated to a voltage level substantially corresponding to the steady-state level; and then the light-emitting diodes are powered (D) by applying each calibrated pulse to the light-emitting diodes by means of the switchable control circuit.

Abstract: Fixed Frequency, Fixed Duration power controls methods and systems are described for application of power to electrical loads. FFFD techniques according to the present disclosure utilize power train pulses with fixed-frequency fixed-duration pulses to control power applied to a load. The load can be any type of DC load. FFFD techniques allows for controlled variation of the fixed length of the ON pulse, the Fixed length of the OFF or recovery period, the total time period for one cycle, and/or the number of pulses in that time period. Applications to electric motors, electric lighting, and electric heating are described. Related circuits are also described.

Abstract: An exemplary LED driving method is adapted for driving multiple LED strings. Each of the LED strings includes single one LED or multiple LEDs connected in series. In particular, the LED driving method includes steps of: obtaining an initial value of a duty-on period of a driving current in a frequency period to thereby acquire a target accumulative luminosity in the initial value of the duty-on period for each of the LED strings; and prolonging the duty-on period of the driving current in the frequency period and assuring an accumulative luminosity in the prolonged duty-on period to be substantially equal to the target accumulative luminosity for each of the LED strings, when the maximum one of the initial values of the duty-on periods of the driving currents in the frequency period for the LED strings is shorter than the frequency period.

Abstract: Provided are a method of controlling a power supply of a display unit of a terminal which can automatically restore the power supply of the display unit, and a terminal for performing the method. The method includes shutting off the power supply of the display unit within a preset time when a power supply shut-off event of the display unit occurs, and restoring the power supply of the display unit when a preset restoration condition is satisfied. Accordingly, even in a case in which a predetermined control application installed in the terminal is shut down due to unknown reasons, the power supply of the display unit may be automatically restored when a preset time arrives, thereby preventing the display unit from being continuously shut off.

Abstract: A projection-type display device according to an embodiment of the invention modulates light emitted from a solid-state light source array and projects the modulated light on a screen. The projection-type display device includes a power source device that generates power used for driving the solid-state light source array using power supplied from a power source, an instant interruption detecting circuit that detects an instant interruption of the power source, and a control device that, in a case where the instant interruption of the power source is detected by the instant interruption detecting circuit, performs control of extinguishing the solid-state light source array during at least a part of an instant interruption period until recovery after the detection of the instant interruption of the power source.

Abstract: A multicolored LED luminaire module is provided that can be controlled using a single driver and only two wires. The LED luminaire module comprises a plurality of LEDs and a sequencer. The sequencer connects each LED to the circuit in a predetermined order. Synchronously with the sequencer, the driver transmits a control signal comprising a time division multiplexed (TDM) signal that combines the driving currents for each LED into one TDM signal. The sequencer and TDM rate are sufficiently fast such that the light emitted by the LED luminaire appears to be the combined light from all the LEDs.

Abstract: Methods, systems and apparatuses for controlling a light through an automatic mode and a bypass mode are disclosed. One method includes receiving physical signaling. Detection of a predetermined sequence of the physical signaling is used to determine whether to control the light in the automatic mode or the bypass mode. The automatic mode provides network control of the light, and the bypass mode bypasses the network control of the light. One lighting system includes a light, a sensor for receiving and sensing the physical signaling, and a controller detecting a predetermined sequence of the physical signaling. Detection of a predetermined sequence of the physical signaling is used to determine whether to control the light in the automatic mode or the bypass mode. The automatic mode provides network control of the light, and the bypass mode bypasses the network control of the light.

Abstract: Saving energy includes at least one object sensor that is coupled to at least one light sensing if at least one object is present adjacent to the at least one light. If it is further determined that the time of day corresponds to a desired start-up time, the at least one light may then be illuminated by a control system.

Abstract: The present invention disinfects countertop surfaces using high intensity ultraviolet energy causing photolysis. The light is directed to the working area of an office countertop or the countertop used in food preparation such as in a residential or commercial kitchen. A motion detector provides a mechanism for disabling the light should a pet or individual enter an area during the disinfection process. The device further includes a fluorescent lamp allowing dual functionality wherein the device can provide conventional countertop lighting or disinfection lighting.

Abstract: A method, apparatus, and system for compensating for lamp lumen depreciation. The method includes operating the lamp under rated wattage for a period towards the first part of operating life of the lamp. Operating wattage is increased at one or more later times. Energy savings are realized. The increases also restore at least some light lost by lamp lumen depreciation. The apparatus uses a timer to track operating time of the lamp. A few wattage changes made at spaced apart times can be made in a number of ways, including changing capacitance to the lamp, or using different taps on the lamp ballast. In one aspect the invention pertains to solid state sources. The invention can pertain to a variety of applications including wide area lighting, indoor lighting, pathway lighting, parking lot lighting, street lighting, under-counter or -cabinet lighting, and others.

Abstract: The invention relates to an illumination system comprising a luminaire which is configured to provide light according to a plurality of preset combinations of illumination level and color temperature, controlled via a control protocol. The system further comprises a user interface comprising means to (manually) select the illumination level and color temperature from said plurality of preset combinations. The number of preset combinations is at least three. The control protocol comprises transition times for transitions between said preset combinations, said transition times being in the range of about 2 seconds to about 5 minutes. The invention further relates to an illumination method using the illumination system and to a controller uploaded with said preset lighting settings. The use of the system in dependence on the activity, time of day or atmosphere in the classroom has been proven to improve the learning behavior of children. It therefore is a learning tool for teachers.

Abstract: An input stage (10) of an apparatus (1) for driving a light-emitting diode (40-42) receives a signal from a power supply (30-32), and an output stage (20) supplies a current to the light-emitting diode (40-42). The peak value divided by the average value of the current forms a ratio. The driving efficiency is improved by providing the input stage (10) with an arrangement (11) for reducing this ratio by manipulation of the signal, without the necessity of using any smoothing capacitors/inductors. The manipulation may comprise an addition of a frequency component to the signal or an adaptation of an amplitude of a frequency component of the signal. This frequency component may be a third and/or fifth and/or seventh harmonic frequency component of a fundamental frequency component of the signal. The arrangement (11) may comprise a resonant tank which may need to be tuned to the frequency component of the signal.

Abstract: An arrangement of an outdoor light enabling ambient light detection comprises an ambient light detector coupled to the outdoor light; and a user interface accessible by a user separate from the outdoor light; wherein the user interface enables controlling the operation of the ambient light detector.

Abstract: A controller for controlling an LED assembly is described. The controller is arranged to—receive an input signal representing a required characteristic of the LED assembly,—convert the input signal to a control signal for the LED assembly,—apply a correction to the control signal to obtain a corrected control signal, the correction being based on a predetermined transient characteristic of the LED assembly,—output the corrected control signal. As such, a better correspondence between a required characteristic and an actual characteristic of the LED assembly is obtained.

Abstract: An object of the invention is to provide an LED drive circuit that can suppress the generation of harmonic noise. The LED drive circuit includes a rectifying circuit an LED array, and a current supply circuit which includes a capacitor and a time constant adjusting element, wherein the discharge time constant of the current supply circuit is set longer than the charge time constant of the current supply circuit, and wherein during a period of time when the magnitude of AC commercial power supply voltage is larger than the light emission threshold of the LED array, current to the light-emitting circuit is supplied mostly from the rectifying circuit, and during a period of time when the magnitude of AC commercial power supply voltage is not larger than the light emission threshold of the LED array, current to the light-emitting circuit is supplied from the current supply circuit.

Abstract: The system, which provides a control signal, includes an over-current control unit, a time clock that provides a periodic time signal, and a clock generator unit that includes a first input terminal, a second input terminal, and an output terminal. The first input terminal is coupled to the time clock and the output terminal is coupled to the over-current control unit. The first input terminal of the clock generator unit receives the periodic time signal and the second input terminal of the clock generator unit receives a modification signal. The clock generator unit generates a clock signal based on the periodic time signal and the modification signal. The output terminal of the clock generator unit provides the clock signal to the over-current control unit, and the over-current control unit provides a control signal based on the clock signal.

Abstract: A LED driving method includes steps of: providing a first pulse width modulation (PWM) signal for determining a brightness of a LED; obtaining a duty cycle of the first PWM signal; and selectively enabling the LED to work with a PWM dimming mode or a direct current (DC) dimming mode according to a relative relationship between a magnitude of the obtained duty cycle and a preset threshold value. Since the LED is performed with a two stage brightness control by use of mixed dimming mode, the driving efficiency of the LED can be improved.

Abstract: A lighting controller may optimize a timeout value of a lamp based on the goals of saving energy and providing occupant comfort. The lamp may illuminate a lighting area. The lighting controller may determine a false-negative rate for the lamp from sensor data that represents a frequency at which the lamp is timed out while the lighting area is occupied. The lighting controller may adjust the timeout value of the lamp over time so that the false-negative rate approaches a threshold false-negative rate. The false-negatives and occupancy periods may be detected from spikes in time distributions of motion data. The amount of energy that the lamp would consume at an increased timeout value of the lamp may be determined from motion data stored while the timeout value of the lamp is at an initial timeout value.

Abstract: In embodiments of the present invention, a method and system is provided for designing improved intelligent, LED-based lighting systems. The LED based lighting systems may include fixtures with one or more of rotatable LED light bars, integrated sensors, onboard intelligence to receive signals from the LED light bars and control the LED light bars, and a mesh network connectivity to other fixtures.

Abstract: A modified bootstrap circuit utilized, for example, in a high voltage DC/DC CMOS buck converter to convert a high input voltage (e.g., 24V) to a regulated voltage (e.g., 4V) for use, for example, by an LED driver circuit. The bootstrap circuit utilizes a feedback diode and a PMOS switch to avoid high reverse diode voltages across a low voltage bootstrap diode. A bootstrapped buck converter implements the bootstrap circuit to generate a high gate voltage on a high-side NMOS switch during all operating phases. The PMOS switch is controlled by the NMOS switch's output voltage to pass a system voltage (e.g., 5V) through the bootstrap diode whenever the output voltage drops low (e.g., 0V), and to shut off when the output voltage subsequently rises such that the feedback diode forward biases to pass the output voltage to the anode of the bootstrap diode.

Abstract: Output stage circuit is added to the gate driving circuit of the LCD. The output stage circuit moderates the falling slope of the gate driving signal so as to reduce the feed-through phenomenon. The output stage circuit includes a discharge circuit which discharges the voltage of the gate driving signal with programmable speeds. The discharge circuit has a plurality of discharge units which are turned on sequentially and designed with different driving abilities. At beginning of falling of the gate driving signal, the discharge circuit discharges the gate driving signal with lower driving ability so that the gate driving signal falls with a lower speed. As time passes, the falling speed of the gate driving signal increases by the increasing of the driving ability of the discharge circuit. The entire falling period of the gate driving signal is prolonged by the output stage circuit and the feed-through phenomenon is eased.

Abstract: In embodiments of the present invention, a method and system is provided for designing improved intelligent, LED-based lighting systems. The LED based lighting systems may include fixtures with one or more of rotatable LED light bars, integrated sensors, onboard intelligence to receive signals from the LED light bars and control the LED light bars, and a mesh network connectivity to other fixtures.

Abstract: A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, sampling a subset of the pulses in the sense signal during that sampling period. The method further includes generating a holding current for the dimmer during the sampling of the subset of pulses in at least one of the sampling periods. In addition, the method includes, for each of the sampling periods, generating an output value identifying a duty cycle for driving one or more light emitting diodes (LEDs). The subset of pulses in each of the sampling periods includes multiple pulses during that sampling period but not one or more initial pulses at a beginning of that sampling period.

Abstract: An example controller for a switched mode power supply includes a comparator, a drive logic, and an on-time extension block. The comparator has an output indicating whether the current through a switch of the power supply exceeds a zero-crossing current threshold. The drive logic is to generate a drive logic output signal in response to the current sense signal and in response to a feedback signal, where the drive logic output signal is representative of an on-time of the switch to regulate the output of the power supply. The on-time extension block is coupled to control switching of a switch and to extend the on-time until the output of the comparator indicates that the current sense signal reaches the zero-crossing current threshold or until the on-time of the switch reaches a zero-crossing time threshold.

Abstract: A ballast for fluorescent tubes and the use thereof for producing fluorescent tube lighting fixtures using a novel gas excitation mode in which light is generated by means of controlled pulses leading to an increased power efficiency, with a data collection and transmission functionality, are disclosed.

Abstract: A light emitting device includes: a plurality of light emitting elements configured to emit light when a direct current is supplied thereto; and a direct current power supply circuit configured to supply an electric current of a given level or more to the light emitting elements. The light emitting device further includes: a light emitting element voltage detection circuit configured to detect a voltage applied to the light emitting elements; and a forward/reverse inverting circuit configured, when the light emitting element voltage detection circuit detects an abnormality in a light emitting element, to apply a reverse voltage to the light emitting element in which the abnormality is detected.

Abstract: A user interface for an indoor light switch coupled to control an outdoor light having a sensor for controlling an on/off state of the outdoor light is disclosed. The user interface comprises a mode actuator moveable between an off position and a sensor position; and a control actuator enabling an adjustment of a setting of the sensor from the user interface, wherein the setting of the control actuator will affect the on/off state of the outdoor light when the mode actuator is in the sensor position.

Abstract: A positive counter starts counting, starting with an initial value, upon receiving a positive edge of a dimming pulse signal. A negative edge counter starts counting, starting with an initial value, upon receiving a negative edge of the dimming pulse signal. For each i-th (2?i?n) channel, the phase shift amount is calculated by multiplying a period count value that indicates the period of the dimming pulse signal by (i?1)/n. When the count value matches the phase shift amount, a burst control signal is switched to a first level. When the count value matches the phase shift amount, the burst control signal is switched to a second level.

Abstract: In various embodiments, a dimmable operating device for the combined operation of a gas discharge lamp and a semiconductor light source is provided. The dimmable operating device may be configured such that only the semiconductor light source is operated in the lower dimming range and only the gas discharge lamp is operated in the upper dimming range, and at the changeover points at which one sort of light source out of the semiconductor light source and the gas discharge lamp is switched off or on, at the same time a jump in power is applied to the other light source out of the semiconductor light source and the gas discharge lamp, with the result that the human eye cannot perceive, or can only perceive with difficulty, the changeover point.

Abstract: Various embodiments of a dimmable power supply are disclosed herein. For example, some embodiments provide a dimmable power supply including an output driver, a variable pulse generator and a load current detector. The output driver has a power input, a control input and a load path. The variable pulse generator includes a control input and a pulse output, with the pulse output connected to the output driver control input. The variable pulse generator is adapted to vary a pulse width at the pulse output based on a signal at the control input. The load current detector has an input connected to the output driver load path and an output connected to the variable pulse generator control input. The load current detector has a time constant adapted to substantially filter out a change in a load current at a frequency of pulses at the variable pulse generator pulse output.

Abstract: A method of controlling the power consumption of a light source in a mobile projector, including calculating power consumption of the light source, and comparing the calculated power consumption with a preset power value, and automatically adjusting current flowing to the light source according to a resultant value of the comparison. Calculating power consumption of the light source includes measuring a voltage applied to both terminals of the light source, measuring current flowing to the light source, and calculating power consumption of the light source by multiplication of the measured voltage and current. Adjusting the current flowing to the light source includes calculating a difference between the preset power value and the calculated power consumption of the light source, adding/subtracting the calculated difference value to/from a preset current value to output a resultant value, and changing the voltage output to the light source according to the resultant output value.

Abstract: The invention discloses an illumination system having a first proximate detector with a first zone detector and a first transmitter. The first zone detector can detect the passing of a human body and the transmitter can send a signal upon such detection. The invention may further include a second zone detector and a second transmitter having similar capacities. In addition, the invention may also have a first staircase illuminator and a second staircase illuminator. Detection of a person passing near a zone detector may cause a staircase illuminator to illuminate a staircase area. The process of transmitting, receiving and illuminating may continue for as long as any of the illuminators within the illumination system that has not yet been illuminated.

Abstract: A light emitting diode (LED) system implements a power management technique. The LED system includes a plurality of LED drivers connected in series, each LED driver configured to regulate the current flowing through a corresponding subset of a plurality of LED strings. Each LED driver determines the tail voltages of the one or more LED strings of the corresponding subset. Each LED driver, except for the first LED driver in the series, also receives a voltage representative of the minimum tail voltage of the other subsets regulated by the upstream LED drivers. Each LED driver then provides the lowest of the voltage received from the upstream LED driver and the one or more tail voltages of the corresponding subset to the downstream LED driver. In this manner a voltage representative of the minimum tail voltage of the plurality of LED strings is cascaded through the series.

Abstract: A decorative light in the form of a candelabrum, chandelier, or sphere, the candelabrum and chandelier having a plurality of artificial flower blossoms, each with an LED. A control circuit is electronically connected to each LED and has electronic circuitry to cause each LED to illuminate at a preselected time each day, remain illuminated for a predetermined interval, and then extinguish.

Abstract: A dimmer switch has a user adjustable high-end trim. The dimmer switch includes a bidirectional semiconductor switch, such as a triac, for controlling the amount of power delivered from a source of alternating current power to a lighting load, such as an electric lamp. A user-adjustable timing circuit controls the conduction time of the triac from a minimum time to a maximum time to control the power delivered to the load between a low-end trim and a high-end trim. The timing circuit includes a user-accessible switch that allows a user to reduce the high-end trim from a first nominal level to a second reduced level, lower than the first level, without substantially affecting the low-end trim. The dimmer switch advantageously uses less energy and the lifetime of the lamp is extended when the second reduced level of the high-end trim is selected.

Abstract: The present invention is related to a switched-mode power supply. It is also related to a LED lighting system and driver which comprise such a switched-mode power supply. In addition, the present invention is related to a method for electrically driving a load. According to the present invention, the switched-mode power supply is switched from a charging state, in which an energy storage is charged, to a discharging state, in which the energy storage feeds a load, when a current limit has been exceeded. This current limit is set proportional to an instantaneous voltage outputted by the rectifier.

Abstract: A light source system includes a luminescent wheel, a driving unit for rotating the luminescent wheel, a light source for shining excitation light on to a luminescent material layer of the luminescent wheel, a light shining control unit for controlling an illumination timing of the light source, a light shining time integrating unit for integrating individual excitation light shining times to a plurality of predetermined divided areas of the luminescent wheel, an integrated light shining time storage unit for storing the individual light shining times to the predetermined divided areas, and a light shining range control unit for equalizing times over which excitation light is shone on to the plurality of predetermined divided areas of the luminescent wheel based on the individual excitation light shining times to the predetermined divided areas.

Abstract: A starter unit (for example, an RF-enabled and replaceable starter unit) has an ability both to turn on and to turn off a fluorescent lamp. The starter unit detects whether a ballast in the circuit with the fluorescent lamp is of a first type (for example, an L-type ballast) or is of a second type (for example, a C-type ballast). If the determination is that the ballast is of the first type, then the starter unit turns off the lamp in a first way (for example, using C-type timing and then using L-type timing alternatingly). If the determination is that the ballast is of the second type, then the starter unit turns off the lamp in a second way (for example, using only C-type timing). The same starter unit design is usable both in single-lamp fixtures and in multi-lamp fixtures where a mix of ballast types may be used.

Abstract: An absence timer table for defining turn-on and turn-off operations in an absence timer mode is set. Then, a current time is checked. Then, it is determined whether or not the current time is an absence timer control start time. When it is determined that the current time is the absence timer control start time, absence timer control is started. Then, it is determined whether or not an input instruction has been received after absence timer control is started. When it is determined that the input instruction has been received after absence timer control is started, setting of the absence timer mode is cancelled. Then, the process ends (return).

Abstract: In a circuit that turns off a fluorescent lamp, clamping circuitry is provided to dissipate energy stored in a ballast when the lamp is being turned off. In a normal state in which the lamp is on, or in a normal state in which the lamp is off, clamping is not performed as long the VDS of a power switch is below a voltage A. In a lamp turn off operation, the switch is turned on for a time period to extinguish the lamp, and is then made to operate as a clamp (operate in its linear region) for a second period of time to dissipate energy that was stored in the ballast. Clamping in the linear region continues for VDS voltages down to B as ballast energy is dissipated, where B is smaller than A. By clamping down to the lower voltage B, re-ignition of the lamp is prevented.

Abstract: A system may include a switch arranged to control a lighting load, a processor arranged to control the switch, and a failsafe circuit arranged to monitor the processor and actuate the switch if the processor fails. The failsafe circuit may have a time constant, and may be arranged to actuate the switch if the monitor signal does not include a pulse during a period of time equal to the time constant.

Abstract: The present invention discloses a multi-color light emitting device circuit, which includes: multiple light emitting device strings of different colors, a timing control circuit, a power regulator circuit, and preferably a dark feedback circuit. Each light emitting device string has multiple light emitting devices coupled in series. The number of the light emitting devices of each light emitting device string is determined by an operational voltage of the light emitting device, wherein at least two of the light emitting device strings have different numbers of the light emitting devices, such that voltage drops of the two light emitting device strings are closer to each other than in a case wherein the two light emitting device strings have the same number of the light emitting devices, and the response time of the light emitting device strings are increased.

Abstract: A power supply device according to one embodiment is configured to control a lighting of semiconductor light-emitting elements, wherein a dimming signal is canceled during a predetermined time period (T) from a timing immediately after power-ON, so as to light on light-emitting diodes to have a predetermined light amount, for example, a minimum light amount. After an elapse of the predetermined time period (T), cancellation of the dimming signal is released to light on the light-emitting diodes to have a light amount instructed by the dimming signal.

Abstract: Apparatus and a method for operating high intensity discharge (HID) lamps at a predetermined substantially constant luminous flux output. A power-time characteristic is developed using a test lamp of similar type and rating to the HID lamps. This characteristic defines the power required at different times, which may be regularly spaced intervals of for example 20 hours, during the operating life of the HID lamps to operate the lamps at the predetermined luminous flux output. The power time characteristic is then “played back” in real time via a microprocessor based master controller for the HID lamps. The communications to the HID lamps may be wireless or hard wired. The result is that the HID lamps are operated at substantially constant lumens resulting in significant energy savings and improved lamp performance.

Abstract: To provide a lighting device in which the luminance of an EL element is maintained even when the EL element deteriorates so that degradation of the lighting device is reduced, the lighting device includes a surface light source portion including an organic EL element, and a control circuit portion provided in a base portion. The control circuit portion counts a lighting time of the organic EL element and controls the luminance of the organic EL element in accordance with the lighting time. Accordingly, the lighting device in which the luminance of an EL element is maintained regardless of degradation of the EL element so that degradation of the lighting device is reduced can be provided.