Durel Corporation

Rogers Corporation

World Properties, Inc.

Robert Allen Kimball

Brian Jeffrey Buell

Harold Gee Yee

David G Pires

William A Coghlan

Mahyar Vahabzadeh

Mark A Seelhammer

Christopher Eric Papke

Kenneth Vi Ung

A light shutter includes a first electrode, a second electrode, and a third electrode, wherein the first and second electrodes are capacitively coupled to each other by the third electrode. The first electrode and the second electrode can be segmented and the segments separately addressed. In a display having a light shutter and an EL panel stacked on the same side of a substrate, there is a common front electrode and separate rear electrodes for operating the light shutter and the EL panel. The common electrode is electrically floating and the rear electrodes are capacitively coupled to each other by the common front electrode. The rear electrodes can be segmented and the segments separately addressed.

Liquid crystal display with split electrode

A power supply for driving an EL panel includes an inverter that produces a polarity reversing voltage at a pair of output terminals. A switching circuit coupled to the output terminals and to at least one EL lamp applies alternating current to the at least one EL lamp in the on state and blocks current from the EL lamp in the off state. The switching circuit includes a first bidirectional switch connecting a first terminal of the EL lamp to a first output terminal and a second bidirectional switch connecting a second terminal of the EL lamp to a second output terminal.

AC switch with zero off current for EL panel

An inverter for supplying alternating current to an EL lamp includes a first charging path, a first discharging path, a second charging path, a second discharging path, the paths intersecting at a node, wherein the node is the output of the inverter from which the alternating current flows. The charging paths include inductive boost circuits having a common inductor.

Single output EL driver producing reduced current spikes

An inverter is coupled to an EL lamp by a high pass filter including a series capacitor and a shunt resistor. The resistor is coupled in parallel with the EL lamp. The high pass filter has a time constant greater than 0.005 seconds and the capacitor has a capacitance at least ten times the capacitance of the EL lamp.

Driving an EL panel without DC bias

An inverter for driving an EL lamp is tapped to provide voltage or current for driving one or more EL lamps and an LCD. In accordance with one aspect of the invention, one side of the pump inductor is tapped for a voltage that drives the LCD.

Inverter for driving EL lamp and liquid crystal display

An inverter for driving an EL lamp is tapped to provide voltage or current for driving one or more EL lamps, LEDs, and an LCD. In accordance with one aspect of the invention, one side of the pump inductor is tapped for a voltage that drives one or more LEDs and the LCD. In accordance with another aspect of the invention, the LEDs are in series with a storage capacitor and are driven by the current pulses to the storage capacitor.

Inverter for driving EL lamp and light emitting diodes

A driver for an EL lamp includes a voltage boost circuit and an H-bridge output having an AC diagonal and a DC diagonal. An EL lamp is coupled across the AC diagonal. A current path is coupled in series with the DC diagonal and limits current through the EL lamp. The current path is either internal or external to the semiconductor device implementing the driver.

EL driver for small semiconductor die

A personal electronic device includes and inverter having a single inductor for powering an EL lamp and a buzzer. The lamp and the buzzer are coupled together to the output of the inverter and are in parallel with each other or are coupled in series between a source of direct current and ground.

Personal electronic device having EL lamp and buzzer powered from a single inductor

A power supply for an EL lamp includes a boost circuit and four semiconductor switches connected as a bridge having an AC diagonal and a DC diagonal having one end grounded. The voltage boost circuit is coupled across the DC diagonal and an electroluminescent lamp is coupled across the AC diagonal of the bridge. The two semiconductor switches coupled to ground are SCRs.

Enhanced inverter for powering an EL lamp

An EL lamp is driven by a flyback inverter having an inductor connected in series with a first transistor which switches on and off at a high frequency. The junction of the inductor and transistor is connected through a switching diode to an output terminal for connection to an EL lamp. A discharge path, including a second transistor, is coupled to the lamp for removing accumulated charge. The second transistor switches on and off at a low frequency for periodically discharging the electrical charge accumulated on the EL lamp. In accordance with one aspect of the invention, several diodes are connected in series with the switching diode to block waste current during discharge of the EL lamp. In accordance with another aspect of the invention, the switching diode is temporarily by-passed to provide the discharge path for the lamp. In accordance with either aspect of the invention, the inverter can produce alternating current through the lamp by adding a capacitor in series with the lamp.

Low cost inverter for EL lamp

An EL lamp characterized by non-linear brightness decay is driven to constant brightness for the life of the lamp by an inverter controlled by a microprocessor. The microprocessor controls the inverter in accordance with a table containing data which is the inverse function of the non-linear brightness decay. The microprocessor tracks the total on-time of the EL lamp and selects the appropriate data from the table for driving the lamp. Control can be analog or digital. If control is analog, the selected data is coupled to a D/A converter which is coupled to the inverter. If control is digital, the selected data is coupled to a counter driving a pulse width modulator which is coupled to the inverter. In accordance with another aspect of the invention, an EL lamp is dimmed a precise amount based upon the data in the table and the EL lamp can be dimmed in unison with other lamp types, each lamp type having a table containing data for dimming.

Open loop brightness control for EL lamp

An electronic watch, either digital or analog, includes an EL lamp powered by a split chip inverter having a low voltage portion incorporated into a first semiconductor chip and a high voltage portion incorporated in a second semiconductor chip. The first semiconductor chip preferably includes all the other low voltage circuitry of the watch, e.g. timer/divider circuitry and logic for driving a display.

Split chip inverter for EL lamp

A power supply for an electroluminescent lamp includes a pair of inverters for alternately powering the EL lamp from a low voltage DC source. A first inverter is connected to a first electrode of the EL lamp and a transistor is connected between the first electrode and electrical ground. A second inverter is connected to a second electrode of the EL lamp and a second transistor is connected between the second electrode and electrical ground. A pulse generator connected to the inverters and the transistors operates the inverters and transistors to power the EL lamp alternately from one inverter and then the other. In one embodiment of the invention, the voltage across the EL lamp is referenced to ground and, in another embodiment, the voltage across the EL lamp is referenced to the voltage of the DC source.

Power supply having dual inverters for electroluminescent lamps

DC bias does not accumulate on an EL lamp connected in series with a switch circuit including, in one embodiment, two, asymmetric, parallel current paths, one current path for each half cycle of the AC. The first current path includes a first diode for preventing DC bias on the lamp, the first diode is in series with a first transistor between a first terminal and a second terminal. The second current path includes a second diode in series with the base-collector junction of a second transistor between the first terminal and the second terminal. The base of the first transistor is connected to the emitter of the second transistor and to a control terminal. The first transistor and the second transistor are opposite conductivity types. The second current path takes advantage of the fact that the current through an electroluminescent lamp is small and uses the control terminal as a source of current for the lamp. In another embodiment, a large capacitor in series with the electroluminescent lamp prevents DC bias from accumulating on the EL lamp.

Low cost AC switch for electroluminescent lamps

An inverter for powering an electroluminescent lamp has a direct current supply terminal, a ground terminal, and a single output terminal. A high frequency pumping circuit stores electrical energy in an inductor having a first terminal and a second terminal. A switching circuit alternately connects the first and second terminals of the inductor to the output terminal at a low frequency. The output from the inverter is a high voltage, low frequency, alternating current.

Growing community of inventors

Gilbert, AZ, United States of America

Robert Allen Kimball