Abstract: The invention provides an organic light emitting diode active driving system with current feedback, thereby a driving current for organic light emitting diode is not affected by variation of characteristic parameters of thin film transistor under an active driving mode. The active driving system in accordance with the invention includes a transistor and a current comparator for driving an organic light emitting diode. The transistor has two current carrying electrodes respectively connected to a cathode of the organic light emitting diode and ground, and a gate controlled by a data signal. The current comparator has two input terminals respectively receive a reference current with predetermined value and a driving current flowing through the organic light emitting diode.

Abstract: A white light-emitting-diode array driver circuit with a multiple output flyback (or forward) converter with output current mode control. The circuit comprises a power supply source and a transformer. The transformer has a primary winding coupled to, and configured to receive current from, the power supply, and a plurality of secondary windings coupled to the primary winding. The circuit also comprises a plurality of light-emitting-diode arrays, wherein each light-emitting-diode array is coupled to one of the secondary windings. A main controller is coupled to a first of the light-emitting-diode arrays and is configured to control a flow of current to the primary transformer winding. The circuit also comprises a plurality of secondary controllers, each of which are coupled to another of the light-emitting-diode arrays. In addition, each of the secondary controllers are configured to control a flow of current to its corresponding light-emitting-diode array.

Abstract: An apparatus and method for applying short pulsed waveforms, on the order of 1 &mgr;s pulses at a frequency of about 5 kHz, to a discharge lamp, such as a low-pressure mercury/argon lamp, in order to shift the ratio of the intensities of two of the mercury lines, in particular the 254 nm and 365 nm lines, of which for a sinusoidal excitation signal the 254 nm line is predominant, towards the higher wavelength. This greatly increases the efficiency of a lamp using phosphors excited by these UV emissions, because of the reduced Stokes shift.

Abstract: A circuit for controlling the power to a load such as motor or incandescent lamp with reduced radio frequency interference employs a microcontroller to trigger a power transistor into a conductive state for supplying power to the load. The power transistor is switched on and off at a controlled slew rate through an integrator circuit coupled between the microcontroller and the power transistor. A zero current detector circuit detects when no current is passing through the load during each half cycle of the live voltage to switch the power transistor off by generating an interrupt request signal which is supplied to the microcontroller. After an operator selected time interval, the microcontroller generates a signal to switch the transistor to a conductive state.

Abstract: A field emission display ("FED") is disclosed having a gray scale range. Input into the FED, initially, is an analog signal input. The FED, by employing an analog to pulse width converter, subsequently converts the analog input to a pulse width output, the width of which directly correlates to the amplitude of the analog input signal. To achieve this design, the analog to pulse width converter comprises a sampler for sampling the analog signal at a predetermined frequency, thereby creating a plurality of samples corresponding to the input voltage. Further, the converter comprises means for holding each of the samples. The output of the holding means is subsequently coupled with a load responsive to the output of the holding means. In one embodiment of the present invention, this load comprises a voltage controlled resistance. The voltage controlled resistance can comprise a convertor for converting each of the samples to a current source and a load for creating a voltage ramp.

Abstract: An electronic ballast for a gas discharge lamp includes an AC to DC converter for changing alternating current at power line voltage to direct current and an inverter powered by the converter and having a series resonant, direct coupled output coupled to the lamp. The inverter includes an AC switch having a diode bridge defining an AC diagonal and a DC diagonal and a transistor connected across the DC diagonal. The primary winding of a filament transformer is connected across the AC diagonal of the bridge and the transistor is coupled to the microprocessor for controlling current through the primary winding. The microprocessor is programmed to close the AC switch while the lamp is starting and to open the switch after the lamp is started, thereby cutting off the filaments from a source of power and reducing the power consumed by the ballast during normal operation. A resistor in series with the transistor is used to detect filament resistance and provide an indication of lamp type.

Abstract: An internal combustion engine-driven discharge lamp lighting apparatus including an internal combustion engine and a generator driven by the internal combustion engine to generate an output voltage and capable of lighting a high-voltage discharge lamp such as a high-voltage mercury lamp, a metal halide lamp or the like without using any ballast including a leakage transformer, to thereby eliminate problems due to incorporation of the ballast therein.

Abstract: A wing tip system for rotor craft includes a downwardly-facing light housing to provide a visual aid to rotor wingtip position. This system is visible to crew members and to adjacent crew, particularly when using night vision goggles (NVG) or other ambient night vision (ANVIS) equipment. This allows tip lighting to be provided in situations where covert helicopter operations are desired. The lighting further is compatible with ANVIS equipment, in that it permits operation noncandescent light in order to prevent blooming or other effects which would otherwise diminish the effectiveness of the ANVIS equipment. The lighting system further has a higher level of illumination, in which rotor tip lighting is increased to become more visible without the use of ANVIS equipment.

Abstract: A smart driver in combination with an LED including a column driver coupled to one terminal of the light emitting device and a row driver coupled to another terminal of the light emitting device to form an addressed circuit. A controllable power supply having terminals coupled to the column and row drivers and a control terminal connected to control power applied between the terminals in response to a control signal supplied thereto. A control circuit coupling the addressed circuit to the control terminal and supplying a unique control signal thereto, whereby a unique amount of power is applied to the addressed circuit.

Abstract: A fluorescent lamp (2) having at least two phosphor coatings (12) on the surface of the sealed lamp bulb, typically an inner surface. There is variable driving means which preferentially activates one phosphor and not the other phosphors, at one arrangement or setting or configuration of the driving means, while at another setting the driving means activates in addition a different or several different phosphors. Each phosphors may be a blend of phosphors and the phosphors and/or blends may be overcoated upon one another forming multiple layers or all mixed together and applied as a one layer coating on the lamp surface.

Abstract: A lighting control system which comprises an AC mains power point, power distribution means coupled to the AC mains, a dimmer assembly comprising one or a plurality of co-located dimmer circuits each coupled to the distribution means to receive AC power therefrom, and each comprising an output port developing an AC power signal of frequency corresponding to the AC mains, each said dimmer circuit comprising a current path between the distribution means and the output port, a switching means located in the current path so as to controllably interrupt passage of current, switch driving means supplying a control signal to the switching means to cause it to interrupt the current path a multiplicity of times within each AC half cycle, and filtering means in the current path between the switching means and the output port arranged to smooth the current therethrough, the filtering means being arranged to attenuate current components at the frequency of operation of the switching means, and not substantially to attenu

Abstract: An energy-saving lighting control system is selectively operable in either a normal mode, in which certain lighting parameters (e.g., maximum and minimum light levels, fade rates, etc.) are preset and lighting level is determined by which of a plurality of inputs requires the least electrical power, or in an off-normal mode (e.g., a calibration or light-adjustment mode) in which certain parameters are adjustable by manually adjusting the position of a movable member, such as a wiper blade in a potentiometer. A microprocessor-based logic and control unit is adapted to automatically switch from the normal operating mode to the off-normal mode in response to movement of the movable member. After a predetermined time period following the most recent movement of the movable member, the logic and control unit stores the new level of the adjusted parameter, and returns to the normal operating mode. Preferably, the system has multiple outputs by which different types of fluorescent lamp ballasts can be controlled.

Abstract: Through a pattern mask, small sections of a semiconductor wafer are exposed successively to light radiated from a mercury-vapor lamp in high-level steps, during each of which the power consumption and discharge current of the mercury-vapor lamp are at a high level, by continuously lighting the mercury-vapor lamp and repeatedly alternating each of the high-level steps and a low-level step during which the power consumption and discharge current of the mercury-vapor lamp are at a low level. The alternation of the high-level step and low-level step is effected while controlling the magnitude of each of the overshoot and undershoot in the waveform of the discharge current for the mercury-vapor lamp below 10%. The exposure method of this invention is effective in avoiding or minimizing the wearing of electrodes of a mercury-vapor lamp. Thus, the mercury-vapor lamp can enjoy long service life while permitting stable exposure over a long period of time.

Abstract: A high frequency ballast circuit for a discharge lamp particularly of the so-called energy saving type adapted to fit into conventional incandescent lamp sockets. The circuit comprises an inductive choke and a transistor switching device connected in series with the lamp and a rectified source of AC supply. The transistor is switched with a high frequency, preferably asymmetrically square, waveform and a diode having a direction of conduction opposite to that of the transistor is connected in shunt across the series-connected choke and lamp. The circuit enables lightweight air core coils to be used for the inductive choke facilitating integral combination of the circuit and discharge lamp into a lamp unit having the same general configuration as a conventional incandescent lamp.

Abstract: A semiconductor arrangement comprises a region of a second type of conductivity formed in a semiconductor body of a first type of conductivity from one surface thereof, an insulating layer on this surface defining an opening above the said region and a resistance layer covering the opening in the insulating layer and comprising a metal silicide compound of silicon with a metal from the subgroups of groups V or VI of the periodic system which contain tungsten, molybdenum or tantalum.