Abstract: A communication system includes a scanning receiver coupled to a first antenna, a plurality of repeaters coupled to a second antenna, wherein each repeater operable on any channel in a band, and a computer coupled to each repeater for controlling the operation of each repeater and coupled to the scanning receiver for obtaining traffic information from the receiver and storing the information in memory. The memory also contains a table of channels and station IDs, wherein a station ID is associated with a particular channel. Each repeater operates on an available channel, as indicated by the traffic information, using the station ID associated with the channel. The repeaters themselves can be used for obtaining traffic information, eliminating the scanning receiver. The repeaters do not have final amplifiers. Instead, a low level combining circuit couples the signals from each repeater to a single linear amplifier.

Abstract: An EL lamp includes hole for receiving fitting attached to a printed circuit board. The fitting has a base, a head, and a neck connecting the head to the base. The diameter of the head is slightly larger than the diameter of the hole and the head fits though the hole by temporarily stretching the lamp. The lamp includes a substrate, a front electrode, a phosphor layer, and a rear electrode. The rear electrode faces the base. Contact to the front electrode is made through a first aperture in the rear electrode and in the phosphor layer. A second aperture, through the front electrode and the phosphor layer, exposes a portion of the substrate that is covered by the rear electrode. The apertures are aligned with two of the holes in the lamp.

Abstract: In a process for making an EL lamp, a rear electrode is roll coated on a temporary substrate, followed by successive roll coatings of a dielectric layer and a phosphor layer. A transparent, conductive layer on a transparent substrate is laminated to the phosphor layer layer and the temporary substrate is removed. The layers are applied from a slurry or ink and bladed to a uniform thickness across the width of the temporary substrate. The process can be continuous using rolls of material for the temporary substrate. The length of a lamp is limited by the length of the temporary substrate. The width of the lamp is determined by the size of the apparatus used to apply and to spread the layers.

Abstract: An EL lamp has a perimeter that is beveled such that the rear electrode is smaller in area than the front electrode due to the 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 between 30.degree. and 60.degree., preferably 45.degree.. For circular or nearly circular lamps, the entire perimeter of the lamp can be cut in a single stroke.

Abstract: At least one conductive layer runs the length of an EL panel and individual lamps are connected to the conductive layer. In one embodiment of the invention, the electroluminescent layer of the panel does not cover a portion of the front electrode and the conductive layer is electrically coupled to the exposed portion of the front electrode. In another embodiment of the invention, the EL panel includes at least two rear electrodes and the conductive layer is coupled to one of the rear electrodes. An insulating layer between the conductive layer and other parts of the EL panel prevents unintended electrical connections to the conductive layer.

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: An EL panel includes lamp materials laminated to a conductive sheet, wherein the lamp materials include a front electrode, a phosphor layer, and a dielectric layer. The conductive sheet is the rear electrode for the EL panel. In accordance with one aspect of the invention, the conductive sheet is metal foil, a layer of a printed circuit board, or a layer on a flex circuit. In accordance with another aspect of the invention, the phosphor layer and the dielectric layer are applied to the front electrode by screen printing or by roll coating.

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 electronic ballast includes a series resonant inductor and capacitor and a filament winding magnetically coupled to said inductor. The filament winding forms a closed circuit with a filament in a gas discharge lamp, wherein the current induced in the winding opposes a portion of the current through the inductor to reduce the net voltage on the filament during normal lamp operation. In accordance with another aspect of the invention, the filament winding is reversely wound with the inductor on a common core to reverse the phase of the current induced in the filament winding from the current through the inductor.

Abstract: An inverter for powering an electroluminescent lamp includes a supply terminal, a ground terminal, a first switching transistor, an inductor, and a second switcing transistor connected in series between the supply terminal and the ground terminal. As implemented in a semiconductor device, one of the switching transistors in a discrete device and the other of the switching transistors is included in the same die as the driving circuit for the switching transistors. The sum of die cost, packaging cost, and external device cost is a minimum for a single, external power transistor.

Abstract: A workstation for cutting glass into panes includes a personal computer having a board for receiving signals from a transmitter and a video board for controlling a second display in addition to and independently of a first display. The first display is for quantitative data concerning the cut pattern, e.g. the dimension of a cut, and the second display is for qualitative data concerning the cut pattern, e.g. a graphic image illustrating the cut. The worker signals the computer by means of the transmitter to indicate that a cut has been completed. The cut pattern is displayed as a series of individual cuts. Only after the worker has signaled that a cut is completed does the computer display the next cut.

Abstract: An electronic ballast includes an inverter producing pulses having a DC component, an output circuit connecting the filaments of one or more lamps in series, and a control circuit for detecting direct current through the filaments. The control circuit includes a capacitor charged by the DC component. When the voltage on the capacitor reaches a predetermined value, the ballast applies a high voltage to the lamps. The predetermined value is not reached unless a direct current passes from the output of the inverter through all lamp filaments to the capacitor. If a lamp filament is not intact, the inverter will not apply high voltage to the lamp.

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: A data processing system includes a backplane and a plurality of logic boards connected to the backplane by a plurality of connectors. In one embodiment of the invention, a set of common points is electrically coupled to the connectors by individual conductive traces between each common point and the corresponding pins of the connectors. The common points are preferably centrally located among the plurality of connectors to reduce propagation delay. A connector can be attached at the common points. The traces are separated from each other by lateral displacement in a single plane. If the backplane is a multi-layered printed circuit board, the traces are separated from each other by vertical displacement between the layers of the printed circuit board or by both vertical and horizontal displacement. The traces to the connectors nearest the common points have a minimum length greater than the distance between the nearest connectors and the common points.

Abstract: An SMR repeater is made agile by adding a microprocessor controlled frequency selection circuit to enable the repeater to operate on any one of several available frequencies in a band. For dispatch service, the output of the repeater is switched to a power amplifier feeding an omni-directional antenna. The repeater scans several frequencies sequentially. If a signal is detected, scanning is halted to provide repeater service, after which scanning is resumed. The frequency agile repeater is coupled to an antenna system having a narrow beam which can be steered electronically. A control computer scans the azimuth of the beam. The computer divides a service area into a plurality of cells extending radially from the antenna system and assigns channels as needed to service a subscriber. More than one cell can be on the same frequency without interference.

Abstract: An electroluminescent lamp includes a continuous electroluminescent dielectric layer and a patterned rear electrode overlying the electroluminescent dielectric layer, wherein the rear electrode includes at least two conductive segments separated by a gap. An insulating layer fills the gap and a conductive interconnect overlies the insulating layer, joining the segments. The insulating layer spaces the interconnect from the electroluminescent dielectric layer a sufficient distance to reduce the electric field in the electroluminescent dielectric layer below the point at which the lamp appears luminous.

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.