Abstract: A cathode-ray tube comprises an evacuated envelope having a faceplate panel with a sidewall joined to a funnel. A shrinkfit implosion protection band surrounds at least a portion of the sidewall and is in contact therewith. A plurality of openings are formed in the implosion protection band to support a degaussing coil. The implosion protection band is improved over prior bands by providing a cavity in the band around at least three sides of each of the openings. The cavity is directed toward the sidewall of the panel so that the openings in the band are spaced therefrom.

Abstract: A luminescent screen assembly for a CRT is made by first coating the interior surface of a faceplate panel with a photoconductive layer which overlies a conductive layer. A multiplicity of red-, green- and blue-emitting phosphor screen elements are then deposited in color groups, in a cyclic order, onto the interior surface of the panel. A negative charge is then established on the photoconductive layer. The charge is weakened in the areas where the photoconductive layer underlies the phosphor screen elements, but unaffected in the open areas separating the phosphor screen elements. The charged, open areas of the photoconductive layer are discharged by flood illumination and reversal developed by depositing thereon particles of light-absorptive matrix material having a triboelectric charge of the same polarity as the charge established on the photoconductive layer. The novel process provides a high opacity matrix.

Abstract: A color cathode-ray tube (CRT) has a rectangular faceplate panel with a major axis and a minor axis. A viewing screen is disposed on an internal surface of the panel. The panel is sealed to a funnel along an edge of a sidewall of the panel. A color selection electrode assembly is spaced from the screen and attached to the sidewall of the panel. An internal magnetic shield has a substantially rectangular base with four corners which is secured to the color selection electrode assembly, and a flange circumscribing an aperture. A substantially continuous shield sidewall extends between the base and the flange. The shield sidewall extends backward along an inner surface of the funnel. The internal magnetic shield is improved by at least two pairs of strengthening ribs which are formed in opposite sides of the shield. The ribs are substantially parallel to the minor axis of the panel and in proximity to the flange of the shield.

Abstract: The invention relates to a manufacturing process for an impregnated cathode for an electron tube and the impregnated cathode obtained in this manner. The method consists in mixing (b) a powder (Y) containing the emissive elements (generally barium and calcium aluminates) with powder (W) of at least one refractory metal (generally tungsten, if necessary mixed with a platinum ore metal), then pressing (c) this mixture into a pellet (1) which is then sintered (d) at a high temperature in hydrogen (approx. 2000.degree. C.). In the prior art of this method, a powder of at least one refractory metal was pressed and sintered and then impregnated, machined, cleaned, etc. The process according to the invention therefore saves many steps in the manufacture of an impregnated cathode with respect to the prior art.

Abstract: A cathode-ray tube has a faceplate panel joined to a funnel. An internal magnetic shield is disposed within the tube and is connected to a bottom surface of a flange of a shadow mask frame. The flange of the shadow mask frame has a plurality of integral shield-retaining clips formed therein. Each of the clips overlaps at least a portion of the shield, to retain it in contact with the flange of the frame.

Abstract: An improved cathode-ray tube includes a viewing screen and an electron gun for generating and directing three electron beams toward the screen. The gun includes at least eight electrodes spaced in order from three cathodes, with the furthest electrode from the cathodes being interconnected to a tube anode. The electrodes form a beam forming region, a first quadrupole lens, a main focus lens and a second quadrupole lens in the path of each electron beam. In the improvement, the second quadrupole lens is positioned on the anode side of main focus lens, with the first quadrupole lens being diverging for defocusing the beams, and the second quadrupole lens being converging for focusing the beams in the horizontal plane.

Abstract: A system for controlling the number of data tracks crossed by the tracking head of a recording/playback device as the tracking head moves in a desired direction over a recording medium includes a counter having n output terminals. The counter is initially set to a count representative of the desired number of data tracks to be crossed as the tracking head moves in the desired direction. An further counter, also having n output terminals individually corresponding to the output terminals of the counter, is set to a predetermined count. Counting pulses are provided to the counter when the tracking head moves in the desired direction and to the further counter when the tracking head moves in a direction opposite from the desired direction. The output terminals are compared and a stop signal is generated when all terminals of both counters show that both counters are in the same state.

Abstract: The present invention is an improvement in a method of screening a line screen slit mask color picture tube that includes coating a faceplate panel of the tube with a photosensitive material, inserting a slit shadow mask into the panel and exposing the photosensitive material by passing light from a line light source through a misregister correction lens and through the slits of the mask. The improvement comprises positioning a skew correction lens between the line light source and the misregister correction lens during exposure of the photosensitive material. The skew correction lens has a surface with a general overall cylindrical shape with deviations from the cylindrical shape being in the four corners of the skew correction lens.

Abstract: A process for forming a color selection mask for a CRT, in a press containing a punch and a counter-punch, after a temperature build-up stage in a shaping chamber, through the circulation of pressurized hot gas injected by inlets placed on the walls of the counter-punch, includes the step of distributing the hot gas through a distribution device to uniformly heat the mask's surface.

Abstract: A display apparatus comprises a CRT having an evacuated envelope including a faceplate with a luminescent screen on the interior surface thereof. An electron gun is disposed within a neck of the envelope for generating and directing at least one electron beam toward the screen. A funnel connects the neck of the envelope with the faceplate. A deflection yoke is disposed around the envelope at the junction of the neck and the funnel. The yoke is attached to the envelope with an adhesive. The envelope further includes a first conductive coating on the interior surface of the funnel, a second conductive coating on at least a portion of the exterior surface of the envelope, and a third coating on the exterior surface of the envelope underlying the yoke and connected to the second conductive coating.

Abstract: The magnetic performance of a color CRT is optimized by firing ferromagnetic components thereof in an exothermic atmosphere to anneal the components and form a stable black iron oxide layer on a surface thereof. The components are introduced into a furnace having such an atmosphere and the components are heated to a temperature sufficient to initiate pre-oxidation of the surface thereof. The temperature is then increased to optimize the magnetic characteristics of the components and at least partially relieve stress therein. The components are next cooled to a temperature at which the thickness of the stable black oxide layer on the surface of the components is optimized. A CRT is manufactured according to the process described above.

Abstract: An optical element such as a rear projection screen for an image display device comprises at least two substantially rigid sheet members each having a first major surface and a second major surface providing a plane of incidence and a plane of emergence, respectively, through which light is transmitted sequentially. A first sheet member comprises a Fresnel lens, and a second sheet member comprises a lenticular lens array on each of the major surfaces thereof. The plane of emergence on the second major surface of the first sheet member includes the Fresnel lens formed of a radiation curable material. A method of making the Fresnel lens is described.

Abstract: A method of fabricating a multi-layered, co-fired, ceramic-on-metal circuit board utilizes a bonding layer of glass. The glass has a coefficient of thermal expansion not greater than that of the metal base. The glass of the bonding layer has a softening point below that of the glass in the multi-layer ceramic so that the glass of the bonding layer flows and bonds to the metal to minimize the lateral shrinkage of the multi-layered ceramic.

Abstract: An implosion-resistant cathode-ray tube has an evacuated envelope with a faceplate panel which includes a substantially rectangularly-shaped viewing portion that extends to a peripheral sidewall. The sidewall has corners and oppositely disposed flattened portions. An implosion protection band, having a predetermined width, extends around the sidewall. A plurality of mounting loops are formed in the implosion protection band, in the direction of the width, to accommodate mounting bolts. Each of the mounting loops is closed adjacent to the sidewall to ensure the structural integrity of the implosion protection band.

Abstract: The present invention provides an improved method of forming a shadow mask for a color picture tube from a flat apertured mask. The mask has an central apertured portion, a solid border portion and a skirt portion. The improved method comprises several steps. First, a flat apertured mask is placed beneath an upper punch. Next, the periphery of the mask at the skirt portion is clamped. The punch then is pressed against the mask to contour the mask in its central apertured and solid border portions. Thereafter, the periphery of the mask at the skirt portion is unclamped, and the solid border portion of the mask is pressed between a bead die and the punch to form a peripheral bead in the solid border portion of the mask. Finally, the skirt portion is swept back to substantially parallel a central longitudinal axis of the formed mask, while the border portion is held between the bead die and the punch.

Abstract: The present invention relates broadly to any type of multi-layered, co-fired, ceramic-on-metal circuit board, as a new article of manufacture.The present invention is more specifically directed to various compositions of MgO-13 B.sub.2 O.sub.3 --SiO.sub.2 system glass-ceramics and compositions of such glass-ceramic and suitable fillers, which are suitable for use in the fabrication of multi-layered, co-fired, ceramic-on-metal circuit boards, in which the co-fired, multi-layered ceramic exhibits desirable electrical properties and a temperature coefficient of expansion which closely matches that of its co-fired metal base, although these compositions may have other uses.

Abstract: An improved color picture tube includes a shadow mask which has a rectangular periphery with two long sides and two short sides. The mask has a major axis, which passes through the center of the mask and parallels the long sides, and a minor axis, which passes through the center of the mask and parallels the short sides. The mask includes slit-shaped apertures aligned in columns that essentially parallel the minor axis. Adjacent apertures in each column are separated by tie bars in the mask. The widths of the tie bars are graded in dimension. The grading is at least partially related to the amount of tie bar stretch occurring in a similar size mask having different tie bar widths.

Abstract: A cathode-ray tube comprises an evacuated envelope which includes a faceplate panel joined to a funnel. A steel shrinkfit implosion protection band having a metallic protective coating thereon is fitted around the periphery of the panel to apply a compressive force thereto. The corrosion resistance of the band is enhanced by providing a metallic barrier layer between the steel band and the metallic protective coating.A method of forming the enhanced corrosion resistant band also is disclosed.

Abstract: A luminescent screen assembly for a CRT is made by first coating the interior surface of a faceplate panel with a photoconductive layer which overlies a conductive layer. A multiplicity of red-, green- and blue-emitting phosphor screen elements are then deposited in color groups, in a cyclic order, onto the interior surface of the panel. A substantially uniform charge is established on the photoconductive layer. The charge is weakened in the areas where the photoconductive layer underlies the phosphor screen elements, but unaffected in the open areas separating the phosphor screen elements. The charged open areas of the photoconductive layer are directly developed by depositing thereon particles of light-absorptive matrix material having a triboelectric charge opposite in polarity to the charge established on the photoconductive layer.

Abstract: The improved color picture tube includes an evacuated glass envelope having a rectangular faceplate panel. The panel includes a shadow mask assembly mounted therein by support means located at the four corner of the panel. Each support means includes a stud attached to the glass envelope. The improvement comprises the support means also including, at each of the four corners, a first spring and a second spring. Each spring is elongated, with a first portion thereof attached to the mask assembly and a second portion thereof cantilevered away from the assembly. The first spring extends peripherally in a first direction with respect to the assembly, and the second spring extends peripherally in a second direction with respect to the assembly. The first spring includes an aperture within the second portion that engages a respective stud. A section of the second portion of the second spring overlaps the second portion of the first spring.