Abstract: A color printing system including thin film electroluminescent (TFEL) edge emitter devices and an electronic interface for driving the TFEL devices. The TFEL edge emitter devices form a multi-color TFEL edge emitter structure operable for emitting a plurality of different colors of light onto a media. The electronic interface receives gray scale data for pixels and converts it into a serial data stream used to drive pixels in the TFEL edge emitter structure. The electronic interface further includes a compensation memory for compensating for pixel variations in the TFEL structure. The compensation memory can be periodically recalibrated "in place" during the life of the printing apparatus.

Abstract: An improved facsimile machine having at least one edge emitting thin film electroluminescent line array, each array having a plurality of pixels wherein the pixels are selectively activated. A light beam from each pixel is directed to a known point along a line on a document and reflects to a sensor. The reflected beam corresponds to a grey level at the point of reflection on the document and causes the sensor to generate a signal corresponding to that greyness level. Sufficient pixels are provided to generate sufficient light beams to strike all points along a line across a document.

Abstract: An improved power saving drive circuit is provided for a multiplexed thin film electroluminescent (TFEL) array having a number of edge emitter devices. The drive circuit includes a charge circuit and a discharge circuit operatively connected to a load capacitance. Although the charge and discharge circuits may contain common elements, the discharge circuit usually has fewer windings than the charge circuit. A voltage regulator is provided to maintain the voltage on the load capacitor during the interval between charging and discharging thereof.

Abstract: A thin film electroluminescent edge emitter structure includes a common electrode layer and control electrodes disposed above the common electrode layer. At least one dielectric layer is disposed between the common electrode layer and control electrodes, and a phosphor layer is interposed between the one dielectric layer and common electrode layer. The common electrode layer, one dielectric layer and the phosphor layer define the light-emitting pixels of the emitter structure. Each pixel has a light-emitting face formed thereon and is operable upon application of electrical excitation to cause the radiation of light energy within its phosphor layer at least in a direction towards the pixel light-emitting face.

Abstract: A power saving voltage drive circuit for a TFEL edge emitter device of the type having a plurality of pixels, with each pixel having a first terminal and all pixels on a device sharing a common second terminal, is comprised of a demultiplexing channel driver being selectively connected to the second terminal. A bidirectional switch selectively connects one of the first terminals to a source of voltage thereby enabling current to flow into and out of the pixel. A transformer has a primary winding connected between the first terminal and the bidirectional switch for enabling the pixel to charge to an operating voltage, and a secondary winding connected in series with a diode across the source voltage and ground for limiting the value of that operating voltage. The bidirectional switch is operated so that a substantial portion of the energy used to charge the pixel is returned to the source of voltage at the end of the pulse duration.

Abstract: A TFEl structure has a multi-layer construction which includes a bottom substrate layer, a lower electrode layer, a middle EL stack, and an upper electrode layer. Forward portions of the EL stack and the lower and upper electrode layers have formed therethrough a series of longitudinal channels and a transverse street connecting the channels and extending along a forward edge of the bottom substrate layer so as to define a plurality of pixels having light-emitting front edges setback from the forward edge of the bottom substrate layer by the width of the street. Rearward portions of the lower and upper electrode layers respectively underlie and overlie a rearward portion of the EL stack but not each other so as to electrically isolate the rearward portions of the lower and upper electrode layers from one another. Also, a bus bar layer overlies the rearward portion of the EL stack and crosses the rearward portion of the upper electrode layer.

Abstract: A thin film electroluminescent edge emitter structure includes a common electrode layer and control electrodes disposed above the common electrode layer. At least one dielectric layer is disposed between the common electrode layer and control electrodes, and a phosphor layer is interposed between the one dielectric layer and common electrode layer. The common electrode layer, one dielectric layer and the phosphor layer define the light-emitting pixels of the emitter structure. Each pixel has a light-emitting face formed thereon and is operable upon application of electrical excitation to cause the radiation of light energy within its phosphor layer at least in a direction towards the pixel light-emitting face.

Abstract: A TFEL edge emitter structure with an EL stack having a linear array of spaced-apart pixels with front edge faces emitting light of non-uniform intensity from different regions has an uniform light emission filter provided across the light-emitting faces of the pixels. The filter takes the form of an exposed photographic emulsion coated directly to the light-emitting faces of the pixels. Alternatively, the filter takes the form of a separate substrate containing the exposed photographic emulsion mounted across the light-emitting faces of the pixels. The exposed emulsion is darker at regions thereof which correspond to regions of the light-emitting edge faces of the pixels with higher original light intensity and lighter at regions thereof which correspond to regions of the light-emitting edge faces of the pixels with lower original light intensity.

Abstract: A device for detecting insulation defects in a cable having a conductor while an electrical signal is impressed on the cable conductor, the device being composed of an ion source for generating an ion cloud and arranged for causing the ion cloud to be displaced along, and to envelop, the cable, a sense conductor arranged to be disposed along, and in proximity to, the cable and to be in communication with the ion cloud, and a plurality of coded position conductors arranged to be disposed along, and in proximity to, the sense conductor and to be in communication with the ion cloud, each position conductor having at least one discrete region covered with insulation arranged in a pattern which differs from one position conductor to another. An alternating signal having a respectively different frequency is applied to each position conductor, the frequency of the signal impressed on each position conductor being different from the frequency of the signal impressed on the cable conductor.

Abstract: A facsimile machine having a thin film electroluminescent pixel array which is used as the controlled light beam source for creating an image on a photoreceptive copying apparatus when the machine is in a write mode and using the same TFEL pixel array as a source of illuminating light to the scanning sensor when the machine is in the read mode. In other embodiments the primary light emission from the pixel array is used in the write mode and secondary emission from the pixels is used for the illuminating source in the read mode. Embodiments of the TFEL array structure include combination with scanning sensors on the same substrate. Other embodiments include the scanning sensor and the pixel array on separate substrates positioned in generally parallel planes.

Abstract: A device for monitoring an electrical cable comprising a conductor surrounded by insulation to locate insulation defects while a signal is impressed on the conductor, the device including an ion generator for creating an ionized atmosphere to envelop the cable, a sense wire assembly disposed in the vicinity of the cable and within the ionized atmosphere so that the signal impressed on the conductor is coupled into the sense wire assembly when the ionized atmosphere envelops an insulation defect, and a circuit for monitoring the signal coupled into the sense wire assembly from the cable conductor. The sense wire assembly comprises a first wire presenting a low resistance to the ionized atmosphere, a second wire presenting a high resistance to the ionized atmosphere, and a circuit unit for producing a sense wire signal which is a function of the difference between the signal coupled into said first and second wires.

Abstract: A method of detecting insulation defects in a wire using an extended ion source wherein ions are generated along the entire length of the extended ion source and flow toward an insulated cable located in close proximity thereto. If there are defects in the cable insulation, a real current will flow through the insulation defects and into the cable conductor. The presence of this real current can be measured by connecting one end of the cable conductor to an ammeter and changes in this current indicate the existence of a defect in the wire insulation. In another embodiment of the extended ion source, the ions are generated only in a small portion of the extended source at any one time. By exciting the source with the proper sequence of signals, the ion generation scans or propagates along the entire length of the extended ion source.

Abstract: A thin film electroluminescent edge emitter structure operable as an electronically controlled, high resolution light source includes a plurality of TFEL assemblies disposed in array-like fashion on a layer of substrate material. Each TFEL assembly includes a first layer of electrically conductive material, a second layer of electrically conductive material spaced from the first electrically conductive layer and an electrically energizable, light-emitting composite layer interposed therebetween. At least the second electrically conductive layer of each TFEL assembly is segmented to provide a plurality of second electrically conductive elements, and the plurality of second electrically conductive elements in combination with the remaining layers of the assembly form a pixel group including a plurality of individual light-emitting pixels.

Abstract: A device is provided for detecting defects in wire or cable insulation which is located in a vacuum without disconnecting the cable by synchronously detecting the current in a sense conductor with respect to the potential waveform existing or imposed on the cable under test. A sense conductor and a scanned extended electron source having a linear cathode array are both placed in close proximity to and along the cable under test. Only a small portion of the cathodes in the linear array are excited at any one time and by placing the proper signals on the excitation conductors of the electron source, the electron generation scans or propagates along the entire length of the extended electron source. The current flowing in the sense conductor due to the electrons from the electron source varies depending upon the presence of defects in the cable insulation.

Abstract: An optically coupled remote sensor apparatus comprises a tuned circuit incorporating a sensor and a light emitting diode (LED) connected in parallel with the tuned circuit. The natural resonant frequency of the tuned circuit is determined by the sensor whose electrical parameter is a function of the condition to be sensed. The sensed condition correlates to a frequency of light pulses emitted from the LED, which light pulses are only emitted when the pulsed light source frequency coincides with the natural resonant frequency of the tuned circit.

Abstract: A thin film electroluminescent edge emitter structure operable as an electronically controlled, high resolution light source includes a plurality of TFEL assemblies disposed in array-like fashion on a layer of substrate material. Each TFEL assembly includes a first layer of electrically conductive material, a second layer of electrically conductive material spaced from the first electrically conductive layer and an electrically energizable, light-emitting composite layer interposed therebetween. At least the second electrically conductive layer of each TFEL assembly is segmented to provide a plurality of second electrically conductive elements, and the plurality of second electrically conductive elements in combination with the remaining layers of the assembly form a pixel group including a plurality of individual light-emitting pixels.

Abstract: A method and device for detecting defects in wire or cable insulation without disconnecting the cable by synchronously detecting the current in a sense conductor with respect to the potential waveform existing or imposed on the cable under test. Both the ion source and the sense conductor are placed in close proximity to the cable under test. The current flowing in the sense conductor due to the ions from the ion source varies depending upon the presence of defects in the cable insulation and the potential waveform present on the cable under test. The synchronous detection enhances the signal to noise ratio of the current measurement.

Abstract: A drift free magneto-optic current transformer for measuring an electric current which may include a d-c component in which two orthogonally polarized light beams are passed through a magneto-optic element operating as a Faraday rotator to rotate the beams through an angle dependent upon the magnitude of the d-c current. An analyzer, oriented with two orthogonal polarization axes set at +45 degrees and -45 degrees with respect to the plane of polarization of the first input light beam and at -45 degrees and +45 degrees with respect to the plane of polarization of the second input light beam, splits each emerging light beam into two output light beams which are converted into a.sub.1 and b.sub.1, and a.sub.2 and b.sub.2 electrical signals in response to the first and second input light beams respectively. By maintaining the signal (a+b).sub.1 equal to (a+b).sub.2, and by maintaining (a-b).sub.1 +(a-b).sub.2 equal to zero, an output signal (a-b).sub.1 -(a-b).sub.

Abstract: Physical quantities such as pressures, accelerations and electrical currents including d-c currents are measured by alternately passing polarized and unpolarized light through an optical-sensor which modifies the polarization of the polarized light in proportion to the magnitude of the physical quantity while passing the unpolarized light unaltered by the physical quantity. The polarized and unpolarized light are generated by separate light sources which generate light at two different wavelengths and a polarizer which is effective to polarize light of the one wavelength but not the other. Light emerging from the sensor is converted into an electrical signal by an analyzer and a photodetector.

Abstract: Drift compensation for the output signal of a magneto-optic current measuring system is achieved through the use of two light emitting sources, each at different frequencies, to generate two alternating optical input signals to the current sensor to establish a signal reference in order to compensate for signal drift caused by variable attenuator characteristics of the optical elements in the system.