Abstract: A cathode-ray tube device for generating a bright light spot is provided, in the path of radiation, a container with a coolant from the cathode-ray tube containing a solution of about 0.5-2.0% by weight of a surfactant selected from the group consisting of sorbitan esters of fatty acids of 12-18 carbons, polyoxyethylene derivatives thereof and ethers of polyoxyethylene in polyethylene glycol 200-300 all of said container in contact with said solution being formed of polymethyl methacrylate and all surfaces of which container are in contact with said solution are provided with a thin layer of silicon dioxide.

Abstract: The present invention provides an improvement in a cathode-ray tube that includes a rectangular faceplate having two long sides and two short sides wherein the ratio of the length of the long sides to the length of the short sides is approximately 16 to 9. The tube includes a major axis which parallels the two long sides and a minor axis which parallels the two short sides. The improvement comprises the ratio of the equivalent radius of the faceplate curvature along the major axis to the equivalent radius of the faceplate curvature along the minor axis being in the approximate range of 1.5 to 1.6, the ratio of the equivalent radius of the faceplate curvature along the long sides of the faceplate to the equivalent radius of faceplate curvature along the major axis being in the approximate range of 1.12 to 1.

Abstract: An apparatus and method provides for installing an implosion panel on the image-display window of an image-display device. The apparatus includes means for spacing an implosion panel from the image-display window a predetermined distance to provide a cavity therebetween. The periphery of the cavity is sealed and uncured resin is introduced in a controlled manner into the cavity while exhausting the air from the cavity. The apparatus includes means for curing the resin to bond the implosion panel to the image-display window.

Abstract: A glass article useful, for example, as a cathode ray tube screen, has a viewing light path which passes through at least one surface region over which the glass is matted by surface pits whereby unwanted specular reflection from that matted region is reduced. The light path also passes through a surface layer formed over a region of the glass so as to reduce the total light reflection from that region of the glass.

Abstract: A large area display has a plurality of cathode ray tubes mounted adjacent each other in X, Y matrix and each cathode ray tube includes a plurality of pixels arranged in an X, Y matrix on a front panel and each pixel comprises three horizontally extending stripe-shaped luminous elements aligned in the vertical direction and the front panel of the cathode ray tube is formed with a thinner portion adjacent its outer edge where it joins to the funnel to reduce the spacing between adjacent cathode ray tubes to a minimum to allow the pixels to be viewed over a wider angle.

Abstract: A cathode ray tube has an insulating layer formed at at least a part of the outer surface of a neck tube.The insulating layer is a layer obtained by coating and baking a sol prepared by dispersing one or two or more metal alkoxides and metal salts in a hydrophilic oligomer state by adding water and an acid to a solution having one or two or more metal alkoxides and metal salts dissolved in an organic solvent such as an alcohol.

Abstract: A color cathode ray tube and an envelope for use with the color cathode ray tube in which a metal plate is interposed between a panel section and a plurality of funnel and neck sections, each of which combination having one electron gun disposed internally. The overall length of the envelope thus constructed can thus be shortened in the direction of the tube axis. The structure of the envelope can also be more simply made and ease of production provided. Further, the envelope can be made lighter in weight.

Abstract: A color cathode ray tube includes a vacuum envelope including a panel having a single glass faceplate including an inner surface and central axis and a skirt extending from the faceplate, a rear metal plate hermetically connected to the skirt through a first connecting member, a plurality of funnels coupled to the rear plate through a second connecting member, and a plurality of necks respectively extending from the funnels. In the vacuum envelope, are provided a plurality of electron gun assemblies respectively received in the necks for emitting a plurality of electron beams, a screen formed on the inner surface of the faceplate for emitting visible light by excitation of the electron beams from the electron gun assemblies, and a mask received in the vacuum envelope so as to face to the screen and having an effective region for allowing passage of the electron beams to impinge on the screen.

Abstract: Disclosed are a method for the fabrication of a color television tube as well as a front panel for trichromatic television tubes. The disclosure can be applied to the reception of high-definition television transmissions. According to the disclosure, the front panels designed for a high-definition television tube screen are elements of the group of surfaces defined byZ=.SIGMA.(C(i).multidot.x.sup.j(i) .multidot.y.sup.k(i)Z(i)=Co(i).multidot.F.sup.-(j(i)+k(i)-1)100.multidot.ABS(Zn-Z)<5.multidot.Zdwhere Z is the dimension of a surface of the group, Zn the dimension of a test surface and Zd the dimension of the maximum value of the dimension of the surface. Co corresponds to a reference surface of the group.

Abstract: A cathode ray tube includes a highly evacuated envelope including a funnel section having one end closed by a faceplate and the opposite end continued to a generally tubular neck section. An internal electroconductive coating is applied to an inner surface of at least the funnel section. Further, an anode button is embedded in a mounting hole defined in the wall of the envelope forming the funnel section and is connected electrically with the internal electroconductive coating. The anode button, embedded in the hole in the wall forming the funnel section, has a circumferentially extending side wall inclined relative to a direction generally parallel to a portion of the envelope confronting the interior of the envelope in alignment with the mounting hole. At least a portion of the inclined circumferentially extending side wall of the anode button is held in electrical contact with the internal electroconductive coating on the inner surface of the funnel section.

Abstract: X-ray attenuating polycrystalline ceramic materials having at least 20 wt. percent cerium oxide are disclosed. In addition, the materials can include one or more X-ray attenuating substances selected from the group including compounds of strontium, zirconium, yttrium, niobium, molybdenum, neodymium and tungsten. The materials can be formed in strong, non-porous bodies such as cathode ray tube funnels.

Abstract: An implosion protected cathode ray tube which comprises a glass envelope having a faceplate; and a layered protective structure deposited over and positioned frontwardly of the faceplate. The layered protective structure includes a first resin-coated layer held in contact with the faceplate, a hard coated layer for protecting the first resin-coated layer and a second resin-coated layer formed between the first resin-coated layer and the hard coated layer. The first resin-coated layer has a hardness which corresponds to 1H or lower of hardness of drafting pencil lead, and an elongation at breakage within the range of 65 to 85%. The first resin-coated layer also has a break strength of 3.5 kilograms per square millimeter or greater. The hard coated layer has a hardness which corresponds to 5H or higher of hardness of drafting pencil lead, and an elongation of 3% or smaller at breakage.

Abstract: A rectangular faceplate panel of a color picture tube of the shadow mask type. In the periphery of the rectangular faceplate panel, a curvature C.sub.PL at a long side peripheral portion is made larger than a curvature C.sub.PS at a short side peripheral portion by a value within a range of from 10% to 100%. Further, a level difference z of a diagonal axis of the rectangular faceplate panel is selected to be large and an average radius of curvature in the diagonal direction of the rectangular faceplate panel is selected to be small. Thus, in the color picture tube of the shadow mask type, the faceplate of can be made to look flat, the doming phenomenon can be improved, and sufficient mechanical strength of the glass envelope can be obtained.

Abstract: A projection television display tube comprising an evacuated envelope (1) having a display window (4) which on its inside has a display screen (5) and in front of which on its outside a transparent second window (6) is provided, a cooling liquid (16) flowing through a space (7) between the display window and the second window from at least one inlet aperture (19) to at least one outlet aperture (17), said space communicating with an expansion vessel. The expansion vessel in the operating condition of the tube is present on the top side of the space and is a gas-filled rigid chamber (20), providing effective compensation for the thermal expansion of the cooling liquid (16) without the flow of cooling liquid being obstructed.

Abstract: A CRT implosion protection system having a resin system releasably bonding an implosion panel to the faceplate of a flat or concave CRT and a tension band system secured around the periphery of the faceplate which exerts compression thereon. The tension band system includes a pair of keeper bars which prevent the tension band from slipping, and which secure an external magnetic shield to the CRT.

Abstract: A color picture tube of shadow mask type includes a faceplate panel mounted on the tube. The faceplate panel has curvatures along its major and minor axes, respectively. When the outer surface contour of the faceplate panel is represented by a three-dimensional expression in the orthogonal coordinate system defined by the X-axis corresponding to the major axis, the Y-axis corresponding to minor axis, and the Z-axis corresponding to the axis of the tube, respectively, curved contours Z.sub.x and Z.sub.y of the faceplate panel along the major axis and the minor axis are so realized as to be approximated by Z.sub.x A.sub.1 X.sup.2 +A.sub.2 X.sup.4 and Z.sub.y =A.sub.3 Y.sup.2 +A.sub.4 Y.sup.4, respecvtively, where X and Y represent distances from the center of the faceplate panel along the X-axis and the Y-axis, respectively, and wherein the constants A.sub.1, A.sub.2, A.sub.3 and A.sub.4 are so selected that the conditions that 0.3.ltoreq.P.sub.x (X=X.sub.1).ltoreq.0.6 and 0.95.ltoreq.P.sub.y (Y=Y.sub.2).

Abstract: A projection cathode ray tube which comprises a glass bulb consisting of a funnel portion having a large opening at one side and a small opening at the opposite side, a panel portion which has the inner surface protruded in a convex form toward the interior of the cathode ray tube and which is sealingly attached to the large opening of the funnel portion, and a neck portion receiving therein an electron-gun, which is sealingly attached to the small opening of the funnel portion, wherein the inner surface protruded in a convex form of the panel portion is polished. A sealing surface in the panel portion does not protrude from a useful screen area in the inner surface of the panel portion. At least three reference points may be provided either on the funnel portion or on the panel portion, or on both of them.

Abstract: In a flat-shaped display apparatus has a face plate, a rear plate, side plates, and necessary electrodes therein, a supporting plate and plural supporting rods which are connected to an edge of the supporting plate at intervals of a certain distance are provided between the face plate and the rear plate. The supporting rods are made of metal and all bonded parts are covered by guide plates so that no adhesive is exposed to the electron beams. Therefore, over-scanning of the electron beams can be made, without the electron beams impinging on the adhesive thereby enabling effective distortion compensation.

Abstract: Projection television display tubes having an evacuated envelope (1) with a display window (4) which on its inside comprises a display screen (5) and in front of which a light permeable second window (6) is provided on its outside, a cooling liquid (16) flowing through the space (7) between the display window (4) and the second window (6) from at least one inlet aperture to at least one outlet aperture (17) namely by temperature differences in said cooling liquid. When in such a projection television display tube at the area of the windows (4, 6) and around the said space (7) a cooling jacket (8) is provided which comprises at least one duct (9) which transports the cooling liquid (6) from the outlet aperture(s) to the inlet aperture(s) of the said space, an effective cooling is obtained at a power between 12 and 25-30 W without external pipes or a heat exchanger.

Abstract: A color cathode ray tube which comprises a face panel including a faceplate having a phosphor screen formed of a pattern of triads of phosphor dots on an inner surface of the faceplate, the phosphor screen, and a color selecting shadow mask having a pattern of apertures for the passage of electron beams therethrough and held flat under tension by the face panel so as to confront, and spaced a predetermined distance inwardly from, the phosphor screen. At least the inner surface of the faceplate is curved so that the pitch between each neighboring apertures in the shadow mask can, while satisfying a predetermined condition relative to the distance between the inner surface of the faceplate and the shadow mask, decrease progressively away from the center of the faceplate towards a peripheral region of the faceplate.

Abstract: A resin composition obtained by adding maleic anhydride to an unsaturated polyester resin composition comprising (I) an unsaturated polyester, (II) a styrene monomer, and (III) at least one polymerizable unsaturated compound, in limited amounts is low in viscosity, excellent in transparency and adhesiveness, able to prevent the generation of surface defects, and thus suitable for treating cathode-ray tubes.

Abstract: The present invention provides an improvement in the appearance of a cathode-ray tube including a rectangular faceplate with an exterior surface having curvature along both the minor and major axes. The faceplate also includes a cathodoluminescent screen on an interior surface thereof. At least in the center portion of the faceplate, the curvature along the minor axis is at least 10 percent greater than the curvature along the major axis. Points on the exterior surface near the ends of the major axis, at the edges of the screen, lie in a first plane which is perpendicular to the central longitudinal axis of the tube; points on the exterior surface near the ends of the minor axis, at the edges of the screen, lie in a second plane which is spaced from and parallel to the first plane; and points on the exterior surface near the ends of the diagonals of the rectangular faceplate, at the edges of the screen, lie in a third plane which is spaced from and parallel to the first plane.

Abstract: Inner specular reflection is suppressed in a flat faceplate for use in a color cathode ray tube (CRT) by forming a flat glass faceplate to have an aft, or inner surface characterized by an undefined roughness. By allowing for an aft surface of undefined roughness, a subsequent lapping process is utilized to produce a predetermined roughness of the aft surface that will substantially eliminate specular reflection from that surface.

Abstract: In a color cathode ray tube, a shadow mask and/or a panel is formed into the following shape. In the shadow mask and/or the panel, a radius of curvature at a central portion in a section taken along an X-Z parallel plane is larger than that at an effective diameter edge portion on the Y axis, and a radius of curvature at an effective diameter edge portion on the X axis is smaller than that at a diagonal effective diameter edge portion. In the panel, a difference between a thickness at an effective diameter edge portion and a thickness on the X axis in a section of the panel taken along a Y-Z parallel plane is maximum at a position between the center of the panel and the effective diameter edge portion on the X axis.

Abstract: The use of a flat faceplate comprised of self-polished float glass substantially reduces the cost of a cathode ray tube incorporating a flat tensioned shadow mask while affording a high degree of video image acuity. The float glass flat faceplate does not require polishing and acid etching to provide a high degree of smoothness in its inner and outer surfaces and, in combination with a flat tensioned shadow mask mounted to the flat faceplate, offers a low cost, easily manufactured and assembled color CRT front assembly.

Abstract: An exposure arrangement for use in a computer-aided design system to produce masks. The arrangement includes a cathode-ray tube which produces an image of the mask on the screen of the tube, and an optical system which projects the image of the mask onto a substrate which is to be exposed. The cathode-ray tube is a high-brightness tube in which the screen is provided with a phosphor which emits in an ultraviolet spectrum and with a cooling circuit for the phosphor. The optical system is designed for use in the ultraviolet spectrum and operates on the ultraviolet image provided by the screen of the high-brightness tube.

Abstract: An electron beam device such as a cathode ray tube having an electron gun (15) comprising a profiled tubular body (22) of a vitreous material. At least some of the electrodes (30, 32, 34, 36) of the electron gun comprising cup-shaped drawn metal members which are push fitted against respective engaging surfaces formed in the tubular body (22). Electrical connections to one or more of these cup-shaped members are point contacts made with lead-out wires (38, 40) held captive in the wall of the tubular body (22). In order to ensure a good point contact, at least the area of the wall in the vicinity of the terminal portion of the or each lead-out wire is flat. In consequence thereof a skirted portion of the or each cup-shaped electrode is flattened slightly against the surface of the wall.

Abstract: A cathode ray tube has an envelope comprising a flat glass faceplate covering an opening defined by a side wall of a metal rear housing and sealingly mounted on a flange provided on the side wall. To increase its flexibility and enable the flange surface adequately to conform with the faceplate edge and accommodate deflections thereof upon, for example, evacuation of the envelope, particularly when a glass frit seal is used, the flange is formed so that it extends from the side wall in one direction, either inwardly or outwardly of the opening, and turns back on itself to provide an outer surface onto which the faceplate edge is bonded. By spacing the portions of the flange extending in opposite directions slightly apart, minor variations in the flatness of the faceplate and/or flange surface can also be accommodated.

Abstract: An electron gun for an electron beam device comprises a vitreous elongate tubular body (22) having a plurality of electrodes (24, 27 to 31 and 33 to 37) provided therein. Electrical connections (50, 52, 54) to at least some of these electrodes comprise respective conductors extending within the thickness of the wall of the tubular body (22). The tubular body is made by uniting inner and outer cylindrical members under the influence of heat while drawing them under sub-atmospheric pressure onto a profiled mandril, the electrical connections (50, 52 and 54) having been prepositioned on the inner cylindrical member.

Abstract: A cathode-ray tube includes a shadow mask mounted therein. The mask has curvatures along its major and minor axes. The curvature along the major axis is greater at the sides of the mask than at the center of the mask.

Abstract: A cathode ray tube useful as a transducer in a recording system is provided with a cylindrical envelope whose length is much longer than its width. An electron gun at one end of the envelope provides an electron beam directed for flow along the longitudinal axis of the envelope. A fiber optics faceplate is positioned to extend longitudinally in a sidewall of the envelope. The inner surface of the faceplate is coated with an electron-sensitive coating and the outer surface is positioned in contact with a recording medium. An array of electromagnets are positioned along the envelope and when energized the electron beam is deflected for repetitive linear scan of the faceplate. For relaxing the requirements of the deflecting system, various techniques are described, including modification of the tube envelope.

Abstract: In a color-picture tube, the conductive coating on the inside of the cone is a suspension without organic constituents. The conductive coating on the inside of the neck, which is contiguous to the conductive coating on the inside of the cone, consists of the aforementioned suspension with an addition of organic constituents. A sharp and scratch-resistant boundary between the conductive coating in the neck and the uncoated area of the neck is thus obtained.

Abstract: A thin cathode-ray tube includes a back section having a surface boundary substantially symmetrical in shape to that of a faceplate panel sealed thereto, the back section suppporting a mount which includes an electron gun disposed within the symmetrical boundary.

Abstract: X-ray attenuating ceramic materials having at least one substance selected from the group including compounds of strontium, zirconium, yttrium, niobium, molybdenum, neodymium and tungsten are disclosed. A zinc compound can be used for fluxing and X-ray attenuation in certain ceramic materials. The materials can be formed into strong, non-porous bodies such as cathode ray tube funnels. Such materials include forsteritic porcelains manufactured from batches containing strontium zirconate. Other X-ray attenuating ceramics contain a mixture of X-ray attenuating substances, including a compound of barium.

Abstract: A cathode ray tube has an envelope comprising a mild steel rear housing (1) with a side wall portion (4) defining an opening over which a flat, glass, faceplate (2) is mounted. The faceplate is sealed in a vacuum tight manner using a compliant pressure bonded seal (10), comprising pressure deformable material such as lead, to the outer, flat surface of a flange (8) of the rear housing which projects inwardly of the opening from the side wall portion.

Abstract: A color cathode ray tube with a shadow mask has a screen partitioned into a plurality of elemental screen areas and electron guns positioned and corresponding to the respecting elemental screen areas, the electron guns generating electron beams to scan the screen. The shadow mask includes effective regions having a number of apertures passed through by the electron beams to impinge on the screen and a non-effective region adjacent to the effective regions. Phosphors as a signal source are deposited on the non-effective regions or the boundaries between the elemental screen areas to emit a light signal by electron beam excitation. A photo-electric transducer is provided facing the shadow mask and to detect the light signal for feed back to a deflection system to control the electron beam deflection.

Abstract: In a vacuum-tight picture-reproducing device having a flat glass faceplate and a metal tray-shaped back case with an outwardly curved bottom and a continuous flange, the flange has a perpendicular extension. The faceplate has end surfaces embraced by the extension and lies on the flange. The end surfaces of the faceplate and the flange with the extension are permanently joined together by a silver-containing tin-base solder. The joint may be covered by a metal layer.

Abstract: Improved bonding in a cathode ray tube (CRT) between its glass funnel and glass faceplate is achieved by applying a thin base layer of a priming agent to an aft portion of the faceplate adjacent to the periphery thereof as well as to the forward edge of the funnel prior to positioning of the CRT components in contact. An intermediate layer of sealing glass frit is then deposited upon either of the aforementioned layers of the priming agent and adheres to the two priming agent layers without forming a re-entrant geometry. By "priming" the two abutting glass surfaces over an area which extends beyond the area of high loading with the priming agent prior to joining these surfaces, bond integrity is ensured and high stress concentration in the seal is avoided. The sealing glass frit may be comprised of a conventional glass cement paste and is also used as the priming agent in a preferred embodiment.

Abstract: A cathode-ray tube includes a rectangular faceplate which has an exterior surface having curvature along both the minor and major axes. The exterior surface of the faceplate includes a rectangular contour near its periphery which substantially lies in a plane which is perpendicular to the central longitudinal axis of the tube.

Abstract: A projection television receiver comprises at least one cathode ray tube for receiving video signals and projecting images therefrom, the tube including a face; a lens mounted adjacent to the face for focusing the images projected by the tube; and a coolant disposed between the lens and the face for absorbing and dissipating heat from the tube, the coolant means including 1,3-butylene glycol.

Abstract: In a color picture tube, curvature of outside face of said face panel is defined by ##EQU1## wherein Z is a distance in a direction of tube axis from an X-Y plane tangential at the center of the face, r is a distance from the center of the face panel to said point therealong, and A and B are constants of positive integers, respectively; thus the face panel excludes point of inflection and the reproduced picture thereon has a flat appearance, without trouble of undesirable doming of shadow mask.

Abstract: The invention relates to a display tube which is cooled by a flow of a translucent cooling liquid through a sealed space adjacent the display window, stimulated by a fluid-driven pump having two chambers, a drive chamber driven by a remotely located active electric motor driven pump, and a pump chamber responsive to the drive chamber and connected to the sealed space. Fields generated by the motor of the electric pump do not interfere with the operation of the display tube.

Abstract: A flat CRT having a phosphor screen inclined with respect to the center axis of an electron beam and formed by applying phosphors to the inner surface of a tube wall. The tube inner surface is defined by rotating a plurality of logarithmic spiral curves having a constant angle of incidence and present in the x-y plane of a polar coordinate system in which the deflection center of the electron beam is its origin, the center axis extends through the origin and serves as the x-axis, and the y-axis extends through the origin and intersects the x-axis at right angles therewith. The spiral curves are rotated about the y-axis each through a specified angle to obtain a group of logarithmic curves defining the tube inner surface.

Abstract: In a cathode ray display tube having a glass faceplate carrying a screen thereon including a screen electrode and an electron multiplier disposed adjacent the screen for current-multiplying an electron beam directed onto the screen, a low profile termination arrangement for establishing electrical connection with the screen electrode and a multiplier electrode comprises respective, spaced, thick film conductive tracks on the inner surface of the faceplate and bordering the screen connected at lead-in portions thereof with conductor means, e.g. conductive epoxy, in apertures extending through the faceplate via metal sealing discs.

Abstract: A flat cathode-ray tube has a tubular glass body comprising a tubular neck portion, a flat funnel portion, a flat box-shaped head portion, an electron gun housed in the neck portion, and a fluorescent screen at the head portion. At least the funnel portion is made entirely of a flat glass plate. A deflection yoke, mounted on the junction of the neck and funnel portions, comprises a core having at its funnel-side end an opening approximately rectangular with substantially straight upper and lower sides and gently outwardly bulging arcuate opposite lateral sides. The core's inner surface, defining an opening, is continuously reducing in size from the funnel side toward the neck portion conforming with the tapered shape of the funnel portion. The yoke further comprises a pair of vertical deflection coils wound around an upper and a lower portion of the core. A pair of horizontal deflection coils, each have horizontal portions extending at least along the opposite sides of the funnel portion.

Abstract: In a flat cathode ray display tube having an electron gun adjacent a rear wall of the tube's envelope which produces an electron beam travelling across the rear wall before being turned in the opposite direction and then deflected onto a screen carried by faceplate opposite the rear wall, getter means is situated in one or more recesses, each defined at least in part by an elongate rib formed in the rear wall, e.g. by pressing, with the recess wall shielding the getter means directly from the gun to prevent contamination. The rib serves also to strengthen the rear wall. A line scanning deflector is similarly shielded.

Abstract: A cathode ray tube has a thin flexible circuit (48) comprising one or more films of polyimide with a plurality of conductive tracks deposited directly thereon for establishing electrical connection between a multi-pin lead through (45) passing through the wall of the tube's envelope (31) and terminals of electrically operable components within the envelope, e.g. electron gun (35) and beam-deflection electrodes (36,39 and 40). A number of track-carrying films may be stacked together to form a laminate structure. Such a flexible circuit avoids outgassing problems and, being thin and flexible, occupies minimal space and is easily routed around internal components to ease assembly.

Abstract: An improved structure for cooling a cathode ray tube apparatus for projecting color images includes a cooling medium contained in a space defined by a front panel of the cathode ray tube, a front panel or lens, and a metallic frame for transferring heat from the tube to the frame. An improvement includes an air or expansion chamber communicating with the defined cooling medium space to permit expansion of the heated cooling medium into the chamber, while preserving the distance between the front panel of the tube and the lens.

Abstract: An efficiently cooled display tube is obtained by pumping a low viscosity liquid having a high heat capacity through a cooling space less than 1 mm. thick on the outside of the display window. A chamber is smoothly connected to the inlet aperture of the cooling space to assure a laminar flow, eliminating swirls which could give rise to refractive patterns in the display picture.

Abstract: A projection picture tube includes a bulb, a sealing chamber disposed in contact with a front surface of a phosphor screen panel of the bulb and sealed with a liquid coolant, and a holding mechanism for holding the sealing chamber by the bulb. The sealing chamber includes a transparent member disposed in front of the phosphor screen panel to be spaced apart therefrom, a heat dissipation member which is disposed between the transparent member and the phosphor screen panel and part of which is in contact with the liquid coolant sealed in the sealing chamber, seal members respectively disposed between the heat dissipation member and the phosphor screen panel and between the heat dissipation member and the transparent member, and a holding piece for holding the transparent member on the heat dissipation member. The holding mechanism is coupled to the heat dissipation member.