Abstract: An inline electron gun for a cathode-ray tube has three cathode assemblies each including a cathode sleeve having a cathode cap closing one end of the sleeve and extending therealong. Each cap has an electron emissive coating thereon and a heater is disposed within each sleeve. The center cathode assembly has a laminated bimetal cathode cap comprising a first layer integral with the sleeve and an overlying second layer with a sidewall portion that is shorter than the sidewall portions of the two outer cathode caps of the outer cathode assemblies. The center cap thus has less thermal mass than the outer caps and the center cathode assembly therefore reaches electron emission temperature before the outer cathode assemblies.

Abstract: A method of producing a luminescent viewing screen using a quadrupole focus mask having apertures substantially larger than the phosphor screen elements is described. The method includes the steps of providing a film of a photosensitive polymeric substance on a faceplate and exposing the film through the focus mask. A first phosphor material is subsequently deposited on the region of the faceplate that was shadowed during the exposure. The process is repeated at different angles of exposure and with different color-emitting phosphor materials until at least two and preferably three different color emitting phosphor materials are deposited to form a cyclic array of screen elements.

Abstract: A stem mold includes an improved first (upper) mold assembly and a conventional second (lower) mold assembly. The first mold assembly includes a conventional mold head and a plurality of lead-weights which are attached to one end of the mold head. The first mold assembly is improved by the inclusion of a novel first mold block which has a plurality of fillet recesses therein which communicate through guide openings with a plurality of buffer-pin-wells extending into a cavity in a second surface of the mold block. A novel lead-weight translator is disposed within the cavity in the mold block. The translator has a translator recess formed in one surface and a plurality of lead-weight apertures extending from the recess through the other surface of the translator. A pin holder is disposed within the translator recess. A plurality of pin apertures are formed through the pin holder and aligned with the buffer-pin-wells in the mold block and also with the lead-weight apertures in the translator.

Abstract: The present invention provides an improvement in color cathode-ray tubes. Such tubes include an electron gun for generating and directing three inline beams, a center beam and two side beams, along initially coplanar paths toward a screen of the tube. The gun includes a plurality of spaced electrodes which provide a first, a second and a third lens for focusing the electron beams. The first lens has a beam forming region for providing substantially symmetrical beams to the second lens. The improvement comprises the combination of the second and third lens. The second lens includes at least one electrode to provide asymmetrically-shaped beams. The potentials applied to the second lens refract electron beams emerging off-axes from the first lens toward the axes. The third lens is a low aberration main focusing lens which provides asymmetrically-shaped beams of substantially constant current density to the screen.

Abstract: A shadow mask for a color cathode-ray tube has a plurality of apertures therethrough. The shadow mask is made from an improved iron-nickel alloy sheet consisting essentially of the following composition limits in weight percent: C.ltoreq.0.04, MN.ltoreq.0.1, Si.ltoreq.0.04, P.ltoreq.0.012, S.ltoreq.0.012, Ni 32-39, Al.ltoreq.0.08, Y.ltoreq.0.6 and the balance being Fe and impurities unavoidably coming into the iron-nickel alloy during the course of the production thereof. An oxide layer comprising a major proportion of maghemite (.gamma.-Fe.sub.2 O.sub.3) and magnetite (Fe.sub.3 O.sub.4), and a minor proportion of hematite (.alpha.-Fe.sub.2 O.sub.3) and yttria (Y.sub.2 O.sub.3) is formed on the iron-nickel alloy sheet and stabilized and bonded thereto by an oxide of yttrium (Y.sub.2 O.sub.3) dispersed at interstitial sites throughout the lattice of the alloy sheet.

Abstract: A photosensitive film on a glass surface is prepared by: dispensing a quantity of aqueous emulsion containing the film constituents on the surface, distributing the emulsion as a layer over the surface, leveling the distributed layer and then drying the layer. To burst any bubbles that form during distribution, and to remove residual effects of the bubbles, a mist of a surface-tension-reducing liquid, such as methyl alcohol, is contacted with the distributed layer during leveling.

Abstract: An electron tube evacuating system includes a manifold section having an evacuation chamber. A tube mounting section has a plurality of evacuation apertures in communication with the evacuation chamber. A plurality of tube mounting members individually hermetically mount tubes to be evacuated onto the mounting section. Each mounting member has an aperture in communication with the evacuation chamber.

Abstract: An electron gun for a high resolution color display tube comprises three inline cathode assemblies, a control grid with three inline apertures, a screen grid with three inline apertures, a screen grid slot plate with three inline substantially rectangular slots each associated with a different one of the apertures in the screen grid, and a main electron lens. The screen grid slot plate is attached to the screen grid on the side thereof facing the main electron lens. Each of the cathode assemblies produces an electron beam having a given beam current. Each of the slots in the screen grid slot plate has an inline dimension and a transverse dimension which are selected for the given beam current to independently control the horizontal and vertical sizes of the spot produced by each of the electron beams at a distance from the electron gun.

Abstract: An aluminized viewing screen structure for a cathode-ray tube includes a faceplate panel having a barrier coating and a heat absorptive overcoating comprising a plurality of layers overlying the aluminum metal layer. The barrier coating and the overcoating are applied to the panel which is preheated to accelerate drying of the barrier coating and the overcoating. The novel process includes (a) tilting the preheated panel to a 60.degree..+-.10.degree. angle relative to a horizontal plane, (b) loading the tilted panel onto a carrier, (c) and advancing the carrier by means of a conveyor in a first direction, through a spray assembly. A plurality of spray guns are mounted on a reciprocating device which moves up and down, that is, in a second and a third direction which is different from the direction of motion of the conveyor. The spray guns are directed substantially perpendicular to the faceplate panel.

Abstract: An electroluminescent film of an activated alkaline earth metal sulfide phosphor is produced by a method utilizing low temperatures for substrate protection and achieving excellent crystallinity and enhanced brightness. A layer of an alkaline earth metal halide and a suitable activatior is deposited on the substrate, heated to melt the halide and treated with gaseous hydrogen sulfide to form the phosphor. A precursor for the halide may be deposited on the substrate heated to melting temperature and treated with gaseous hydrogen halide to form the halide in-situ.

Abstract: A current control circuit for high voltage applications includes series-connected high and low voltage sources through which the current to be regulated flows. The low voltage source is a capacitor which is periodically recharged through a flyback transformer by a series of constant energy pulses having a very low duty cycle. The peak value of the flyback pulses are detected to provide a "condition signal" which is representative of the state-of-charge on the capacitor and can be used to protectively inhibit operation of the control circuit and can, in a variant of the circuit be used as an error control signal to maintain the current at a constant level. In the preferred embodiment a sensing capacitor is placed in parallel to the pulsed capacitor to detect the fluctuations in potential and form a sense current which is representative of the regulated current and which is used in a feedback loop to form a control signal for maintaining the regulated current constant.

Abstract: Phosphors are coated and deaggregated by treatment with ultrasonic energy during the coating step. The phosphor aqueous dispersion is continuously passed through an ultrasonic chamber at a rate of flow so as to prevent aggregated phosphor particles from settling out and avoiding deaggregation.

Abstract: A flushing system is provided for a light valve of the Schlieren dark field type. A small amount of filtered fluid is injected into the space between the rotating disc and the output window of the light valve. This is done by injecting the fluid through the center disc bearing, thereby providing a uniform radial flow outwardly from the center and flushing out any particles in the space and preventing any particles in the surrounding fluid from moving into the raster area. By properly regulating the flow of the center flush fluid, the disc can be floated off the support during rotation. This reduces wear generated particles which contribute to substrate buildup and subsequent loss of light throughput. In addition, erratic disc motion caused by a stick and slip frictional effect is reduced.

Abstract: A laminar flow electron gun (16) for use in a light valve of the Schlieren dark field type is disclosed. The gun uses three accelerating electrodes (111, 112 and 113) with critical axial spacing to beam diameter ratios to allow independent adjustment and/or modulation of beam current density at the imaged aperture while reducing criticality of electrode voltages on the second and third accelerating electrodes. The design permits, but does not require, the use of a separate control grid electrode (110). The first accelerating electrode (111) is closely spaced to the cathode (119) to provide a virtual cathode at, or about, the voltage level of that electrode that reduces the thermal beam spread normally encountered in conventional electron guns. Primary control of the narrow angle beam current is by adjustment of the beam current density impinging on the final aperture (121) in the gun.

Abstract: A neutralizing electrode is provided in a light valve of the Schlieren dark field type. The purpose of this neutralizing electrode is to neutralize the large electrostatic forces which develop between the transparent conductive electrode on the rotating disc and the face plate of the light valve causing erratic rotational motion of the disk. The neutralizing electrode is connected to a source of potential which is of the same polarity and substantially the same the potential as that of the rotating disk electrode.

Abstract: A novel electron gun for a cathode-ray tube includes at least one and preferably three cathode assemblies and at least four successive electrodes longitudinally spaced from the cathode assemblies. Each of the electrodes has at least one and preferably three electron beam apertures therethrough. The cathode assemblies and two of the electrodes are attached to a ceramic support member which is the sole supporting interconnection therebetween. A third electrode of the four successive electrodes has a distal electrode member and a proximal electrode member. The proximal member also is attached to the ceramic support member to form a first gun module. A second gun module includes a fourth electrode of the four successive electrodes which is in spaced relation to the distal member of the third electrode. The fourth electrode and the distal member of the third electrode are interconnected by a pair of insulative spacers.

Abstract: A light valve of the Schlieren dark field type is provided with a vacuum envelope containing an electron gun, a focus and deflection assembly and a rotating disk coated with a light modulating fluid on which an electron beam from the electron gun is scanned in a raster pattern. The rotating disk has a transparent electrode which serves as as electron beam landing electrode. Between the focus and deflection assembly and the rotating disk is a drift ring assembly comprising at least two axially separated segments. The drift ring segment closest to the focus and deflection assembly is operated at a voltage to generate, in combination with the focus and deflection assembly, an electrostatic lens which corrects distortions that originate from deflection fields applied to the focus and deflection assembly.

Abstract: A relay switch in an ac main line has a dc-powered applying for applying amplified control sensor signals to the control circuit of the relay switch. To provide dc power for the amplifier when the relay switch main controlled current conduction path is conductive, a current transformer primary winding is arranged in series with that path, and the voltage appearing across the secondary winding is rectified. To provide dc power for the amplifier when the relay switch main controlled current conduction path is non-conductive, an open-circuit voltage related to that appearing across the open-circuit non-conductive path is rectified. To permit the use of one rectifier for developing dc power for the amplifier it is advantageous to apply the open-circuit voltage to the secondary winding of the current transformer through a dc-blocking capacitor with sufficient ac impedance to restrict ac flow across the open-circuit relay switch path.

Abstract: A containment shield for a replaceable Xenon lamp and reflector module provides a safe, simple means of replacing and handling an arc lamp (10) for a light valve projection system. Guides (93, 94) are provided which act as a means of positioning and allowing easy removal of a lamp module (97). These guides also provide the mounting structure for a spring (112) that locks the lamp module into the guides to prevent removal unless the containment shield or shutter (91) is on and the means for releasing the shutter once the lamp module is in place. A shutter release screw (110) is locked into its mounting bracket to prevent its total removal. This insures that the screw will be there to release a shutter and not be removed or lost. The lamp module itself is composed of a rectangular mount plate (99) which provides the support for the arc lamp (10), reflector (100) and other components.

Abstract: A light valve projector system having an improved apparatus for heating the light modulating fluid. The light modulating fluid is heated with near infra-red radiation which passes though the enclosing glass envelope and which is absorbed by the light modulating fluid.