Abstract: A cathode-ray tube including feedback means capable of producing a feedback signal indicative of the position, in at least two dimensions, of a scanning electron beam. The feedback means comprises a plurality of feedback elements disposed at selected locations within the tube enclosure. With a shadow-mask type CRT, the elements are formed on the gun-side surface of the shadow mask itself. With other kinds of CRT's, the elements are formed either on an interior supporting member or on the interior surface of the display medium. In one embodiment, the elements are formed of a phosphorescent material. In other embodiments, the elements are formed of materials capable of producing, upon excitation by a scanning electron beam, signals of visual or electrical character. The signals thus produced may be employed in a closed-loop correction system to accomplish automatic convergence and/or geometric adjustment of a displayed image.

Abstract: The drive circuit of the present invention is characterized by a second amplifier for amplifying the video signal which controls the voltage at the control grid G.sub.1 of the cathode-ray tube. This second amplifier has a wider bandwidth than the similar amplifiers of the prior art. It therefore generates a signal having a lower dynamic range than the dynamic ranges of the output signals associated with the similar amplifiers of the prior art. To compensate for the lower dynamic range of the output signal generated by the second amplifier, the drive circuit of the present invention measures the current in the cathode of the cathode-ray tube, converts this measured current into a voltage, stores the voltage in a capacitance, and amplifies the stored voltage in a fourth amplifier. The fourth amplifier generates a signal having a wider dynamic range than the dynamic range of second amplifier. The output of the fourth amplifier is combined with the output of the second amplifier.

Abstract: A system for recording graphic information, stored in digital form in a data memory, on a moving record medium comprises a controller which is responsive to the travel rate of the moving record medium to supply digital signals from the data memory to a recording member in synchronization with the movement of the record medium.

Abstract: An improved lateral convergence deflection system for a delta-gun shadow mask color CRT includes first, second and third lateral convergence coils mounted on the CRT neck radially outward from the paths of the electron beams from the three guns. The coils are connected in series electrically, and are of suitable strength and orientation to provide a substantially unidirectional, vertical field in the path of one (e.g., the blue) beam, and field nulls in the paths of the other two (e.g. the red and green beams). By varying the current passed through the coil by a convergence drive amplifier, the blue beam may be shifted laterally without producing any substantial movement of the other two beams.

Abstract: Thin film multilayer technology is used to build microminiature electromechanical switches having low resistance metal-to-metal contacts and distinct on-off characteristics. The switches, which are electrothermally actuated, are fabricated on conventional hybrid circuit substrates using processes compatible with those employed to produce thin-film electrical circuits. In a preferred form, such a switch includes a cantilever actuating member comprising a resiliently bendable strip of a hard insulating material (e.g., silicon nitride) to which a metal (e.g., nickel) heating element is bonded. The free end of the cantilever member carries a metal contact, which is moved into (or out of) engagement with an underlying fixed contact by controlled bending of the member via electrical current applied to the heating element.

Abstract: A non-linear amplifier circuit that may be used to provide a logarithmic amplification characteristic. The circuit includes an amplification stage employing positive non-linear feedback for low level input signals to reduce the input capacitance of the amplifier. For large level input signals the feedback is eliminated.

Abstract: An improved calibration reference signal generator that includes both preset and variable means for generating digital signals corresponding to reference voltage levels. The digital signals are coupled through a chopper switch to a first DAC, which produces a square wave analog signal having an amplitude equal to the desired reference voltage. The digital signals also are coupled directly to a second DAC, which converts at least the most significant bit of the signals to a corresponding offset voltage. An output amplifier combines the square wave signal and offset voltage to produce an output square wave signal with a d.c. offset proportional to the amplitude of the square wave signal. In an alternative mode of operation, the output of the second DAC is disconnected from the output amplifier, which then produces a square wave signal without any offset.

Abstract: This invention is designed to protect a resonant scan deflection transistor in a deflection circuit from extremely high flyback voltage pulses. The deflection transistor is protected against high flyback voltage pulses even though: the B+ voltage on the deflection circuit varies over a wide range, the rate of the base drive signal varies over a wide range, and the turn-off delay time of the deflection transistor varies from device to device and for any one device as the base drive signal rate changes. The circuit of this invention compensates for the variations in turn-off delay time (t.sub.D) of the deflection transistor at different horizontal scanning rates, and, in response to this compensation, compares the B+ voltage level with the current in the deflection coil. An extra turn-off trigger signal is developed in response thereto for energizing the deflection transistor drive circuit. In response to the trigger signal, the deflection transistor turns off.

Abstract: A multiburst test signal generator and a method for using the generator's test signal to determine the frequency response characteristics of television video circuits with a high degree of accuracy is described. One of the burst frequencies is continuously enabled and made variable and the other burst frequencies are disabled. The resulting continuous sine wave is applied to the circuit being tested, its frequency is varied, and the output of the circuit being tested is monitored with a conventional frequency counter.

Abstract: Microchannel plates having increased gain and significantly improved aging characteristics are provided by forming a thin film of a cesium compound on the channel walls. In an exemplary embodiment, a surface film of cesium hydroxide is applied to the interior wall surfaces of an MCP by saturating the plate with a solution of the compound, then allowing the solvent to evaporate. The cesium hydroxide residue on the walls subsequently is converted to cesium oxide by a high temperature bake.

Abstract: An improved bistable storage target structure for a cathode-ray tube includes a faceplate-supported transparent target electrode covered by a transparent insulating layer. Overlying the insulating layer is an apertured web collector electrode and a storage component of secondary emissive material formed by a plurality of phosphor deposits disposed within the web apertures. A patterned layer of insulating material is provided overlying the web electrode to isolate the phosphor deposits from the collector electrode.

Abstract: Metallic sputtering targets having minimal mobile ion contamination are produced by forming a compacted slab of particles of the constituent metal(s) in an isostatic pressing operation. The slab is then transferred to a heat resistant support faced with a material, such as alumina, that is inert at high temperatures. Next, the supported slab is placed in a vacuum oven and heated to a temperature sufficient to bond the metal particles together and volatilize mobile ion contaminants. The sintered slab is usable as a cathodic sputtering target with minimal additional treatment. The level of mobile ion contaminants in the completed target may be monitored by fabricating an MOS capacitor using the target, plotting its capacitance versus applied voltage over a suitable range, then measuring the extent to which the plot shifts after a high temperature-positive bias stress treatment.

Abstract: A chroma keying system which prevents the production of a chroma key signal when the primary color signals are equal is described. This system effectively prevents chroma keys on monochrome portions of color foreground camera signals. These monochrome portions are typically caused by uneven studio lighting and the resulting shadows and reflections. The system includes a comparator which compares the R, G, and B signals and generates an inhibit signal therefrom. This inhibit signal is then used to prohibit the generation of a chroma key signal.

Abstract: A color difference between stored and write-through (unstored) information displayed by a direct viewing bistable storage CRT is achieved by admixing the storage phosphor with a second phosphor that emits light of a distinctly different color. The second phosphor is chosen to have a lower relative light output efficiency than the storage phosphor under low voltage, flood gun illumination conditions.

Abstract: An improved method of completely erasing images stored by memory-type electroluminescent display panels. The method comprises interrupting the a.c. sustaining bias signal normally applied to the panel and impressing an erase pulse that is opposite in polarity to the last-preceding sustaining pulse or cycle. The amplitude and duration of the erase pulse are chosen to effect relaxation of the EL layer's internal field. The sustaining bias signal is then restored to place the panel in an erased, ready-to-write condition.

Abstract: Thin-film microcircuit structures passivated with silicon nitride are provided in which included electrical components containing nickel, chromium or other nitride-forming metals are encapsulated in an oxide material, preferably silicon oxide. The metal-containing components are thus prevented from reacting with the silicon nitride passivation coating during through-passivation laser trimming of the components.

Abstract: A cathode-ray tube for a multipurpose test and measurement or information display instrument is provided with multiple internal graticules. One of the graticules is permanently visible and functional at all times the instrument is in operation. Another of the graticules is formed in a manner such that it is not easily visible in normal ambient lighting conditions alone, but becomes plainly visible when edge lighted by suitable means.

Abstract: Improved, high performance MOS transistors are provided by a method that includes providing an oxygen-impermeable mask on a selected region of a semiconductor substrate, oxidizing the unmasked portion of the surface to provide a thick oxide at least partially recessed in the substrate, which layer includes a smoothly tapered beak that extends between the margin of the mask and the underlying silicon surface, and, after removing the mask, implanting a selected impurity in the substrate beneath the selected region to form a thin impurity layer that terminates at a sloped portion of the substrate formed by the oxidation step.

Abstract: A method for reducing the phosphorus concentration in exposed surface areas of a phosphosilicate glass microcircuit layer to reduce the corrosivity of the layer. The method comprises a two step treatment of the layer surface: first, exposing the surface to water vapor at an elevated temperature for a time sufficient to hydrate available phosphorus in a region adjoining the surface, and second, removing the resultant acidic hydration products by rinsing the surface with water.

Abstract: An improved bistable storage target structure for a cathode ray tube includes a faceplate-supported apertured web collector electrode and a discontinuous layer of secondary emissive material formed by a plurality of phosphor deposits disposed within the web apertures. A layer of insulating material is provided overlying the web electrode to electrically isolate the phosphor deposits.