Abstract: An electroluminescent lamp unit includes a flat deformable substrate of preselected size having smaller sheet-form flexible electroluminescent lamps secured face-to-face at preselected positions on a surface of the substrate, the lamps connected with conductive traces on the substrate. The flat substrate with secured lamps can be deformed into a desired shape to provide a relatively inexpensive and reliable electroluminescent lamp unit applicable for a wide variety of applications. The flexible electroluminescent lamps of the unit can be individually addressable and may have different colors or intensities. A method of manufacture of such units employs surface mount technology in an automated version, pick and place robots select and place the lamps as instructed, followed by ultrasonic welding or mechanical or adhesive fastening.

Abstract: An EL lamp has a perimeter that is beveled and said rear electrode is smaller in area than said front electrode due to said bevel. The lamp is made by placing an EL panel on a concave die with the rear electrode in contact with the die and shearing the edge of the lamp at an acute angle. The angle is between 30.degree. and 60.degree. and is preferably 45.degree.. The die has a radius of curvature that is 50-150 times the thickness of the panel to prevent deformation of the panel. For circular or nearly circular lamps, the entire perimeter of the lamp can be cut in a single stroke.

Abstract: A movable pointer includes an elongated, translucent substrate having an EL lamp covering one side of the substrate. The pointer emits light from an adjoining, narrower, front side which is roughened slightly. The ends of the substrate are capped or coated to prevent light emission. A second EL lamp can be attached to a second side of the substrate. The width of the EL lamp can be tapered to provide a pointer which is brighter at one end than at the other. Electrical connection to the EL lamp is made with a compliant ribbon having conductive stripes on one or both sides thereof. The ribbon is mechanically and electrically attached to contacts on the EL lamp.

Abstract: An EL lamp is charged to a first polarity with a series of high voltage pulses, discharged at a controlled rate, charged to a second polarity with a series of high voltage pulses, and discharged at a controlled rate, thereby producing an alternating current through the lamp. A flyback circuit provides the high voltage pulses. The polarity of the pulses is reversed periodically at a low frequency and the EL lamp is prevented from discharging through the flyback circuit by a phase shift circuit that produces a discharge pulse in advance of each change of polarity of the high voltage pulses. The discharge pulse interrupts the high voltage pulses and discharges the EL lamp through a constant current load.

Abstract: An electroluminescent lamp has a luminescent layer placed between a rear electrode layer and a top electrode layer, which is at least partially transparent to light. The electrodes are arranged to excite the luminescent layer by applying a potential to the layer. An insulating layer is placed between the rear electrode layer and the luminescent layer, to increase the capacitance of the lamp. At least one of the layers includes a terpolymer, e.g., vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene. In some applications (e.g., in wristwatches), the luminescent layer includes phosphor, the insulating layer includes barium titanate, and the rear electrode includes silver, all distributed through the terpolymer. In other applications (e.g., in cellular phones or pagers), the rear electrode includes carbon.

Abstract: An EL lamp includes a strip of EL material within a translucent cylinder, preferably a glass tube. The tube can be frosted or coated to further enhance the appearance of the lamp. The strip can be flat or curved and, in an alternative embodiment of the invention, the lamp includes a glass fiber between the light emitting surface of the strip and the tube for gathering light from the strip and emitting the light in a preferred direction. The tube is an optical element combined with the strip to produce the unexpected result of having the tube appear luminous, even without coatings to enhance this effect.

Abstract: An analog display includes a dial and a movable EL pointer positioned adjacent the dial for indicating a measured value. The pointer is an elongated EL lamp having a conductive pin extending through one end of the lamp and about which the lamp pivots. The pin is mechanically secured to the lamp and is electrically connected to the front electrode of the lamp. A hole larger than cross-sectional diameter of the pin is formed in the rear electrode and in the phosphor layer to prevent the pin from shorting the front electrode to the rear electrode. A conductive spring rests on the pin to provide electrical power to the front electrode. Power is supplied to the rear electrode either through a conductive ferrule attached to the rear electrode or through a resilient wiper. The wiper can be attached to the pointer or to the face of the dial. For plural pointers, concentric conductive pins are used with a sliding contact for the rear electrodes.

Abstract: An EL panel has the material around each lamp removed to form a first rail and a second rail and a plurality of lamps mechanically isolated from each other and located on predetermined centers between the rails. Each lamp is connected to each rail by an arm and each arm includes a hole for locating the panel in a fixture. The arms are collinear and intersect the rails at an angle of 45.degree.. The panel is located in a fixture by pins through the holes in the arms and laminated to a backing plate or other device, also located in the fixture.

Abstract: An EL panel includes a pair of EL lamps on a common substrate, separated by a predetermined distance along a longitudinal axis. A first flexible, electrically conductive trace on the substrate interconnects the front electrodes of the lamps and a second flexible, electrically conductive trace on the substrate interconnects the rear electrodes of the lamps. The lamps share a common front electrode and the first trace overlies the front electrode between the lamps. One of the lamps is rotated relative to the other to position the lamps one above the other in separate, parallel planes.

Abstract: An electroluminescent lamp unit includes a flat deformable substrate of preselected size having smaller sheet-form flexible electroluminescent lamps secured face-to-face at preselected positions on a surface of the substrate, the lamps connected with conductive traces on the substrate. The flat substrate with secured lamps can be deformed into a desired shape to provide a relatively inexpensive and reliable electroluminescent lamp unit applicable for a wide variety of applications. The flexible electroluminescent lamps of the unit can be individually addressable and may have different colors or intensities. A method of manufacture of such units employs surface mount technology in an automated version, pick and place robots select and place the lamps as instructed, followed by ultrasonic welding or mechanical or adhesive fastening.

Abstract: An electroluminescent lamp includes at least one bus bar attached to an electrode of the lamp. The bus bar has a gap and a conductive trace bridges the gap. The trace is preferably an isolated segment of the front electrode of the lamp and is made when the front electrode is patterned. The bus bar includes at least one pair of holes extending through the bus bar. The holes each have a diameter less than the width of the bus bar and are spaced along the length of the bus bar. The segment of the bus bar between the holes can be curved to define a path through the holes adjacent the bus bar. A conductive pin through the holes makes electrical contact with the bus bar and is held in place by the holes and the curved segment. The bus bar is an integral connector and the conductive trace is an integral fuse.

Abstract: An EL lamp includes a transparent electrode, an electroluminescent dielectric layer overlying the transparent electrode, a patterned insulating layer overlies selected portions of the dielectric layer for reducing the electric field across the selected portions of the electroluminescent dielectric layer, and a rear electrode overlying the insulating layer and the electroluminescent dielectric layer. The insulating layer is preferably a low dielectric constant material and can overlie the electroluminescent dielectric layer or can be located between a separate dielectric layer and a phosphor layer. A gray scale is produced by depositing or printing more than one thickness of insulating layer.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An electroluminescent sheet-form lamp with a main portion of a conductive layer isolated from an edge region susceptible to detrimental conductive pathways by isolation provided along at least a portion of the perimeter of the lamp as a result of removal of a preapplied conductive coating such that, at the region of the isolation, the main portion of the one conductive layer which forms the respective electrode commences at a line spaced inwardly from the outer edge of the lamp. The preapplied conductive coating material may be removed to form a line of interruption that leaves in place a narrow margin of conductive coating in the edge region which is electrically isolated from the main portion of the coating forming the first electrode. The lamp may be formed by exposing preselected portions of the preapplied conductive coating to laser radiation sufficient to remove the preselected portions and form the region of isolation.

Abstract: 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.

Abstract: An electroluminescent sheet-form lamp comprising a transparent insulation layer, a transparent first conductive layer below the insulation layer forming a first electrode, a layer of phosphor material below the first conductive layer, a layer of dielectric material below the phosphor layer, a second conductive layer below the dielectric layer forming a second electrode, and electrical connection means for applying an electrical potential between the conductive layers to cause the phosphor to transmit light through the transparent conductive layer and the transparent insulation layer, one of the conductive layers having been formed as a general conductive coating preapplied over a panel of larger dimension than the lamp, from which the lamp has been cut.