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WO2001029870A1 - Tube cathodique economiseur d'espace a electrode a double potentiel - Google Patents

Tube cathodique economiseur d'espace a electrode a double potentiel Download PDF

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Publication number
WO2001029870A1
WO2001029870A1 PCT/US2000/028927 US0028927W WO0129870A1 WO 2001029870 A1 WO2001029870 A1 WO 2001029870A1 US 0028927 W US0028927 W US 0028927W WO 0129870 A1 WO0129870 A1 WO 0129870A1
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WO
WIPO (PCT)
Prior art keywords
faceplate
tube
screen
electrode
potential
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2000/028927
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English (en)
Inventor
Arthur Herbert Firester
Dennis John Bechis
Joseph Michael Carpinelli
George Herbert Needham Riddle
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Sarnoff Corp
Original Assignee
Sarnoff Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/559,809 external-priority patent/US6541902B1/en
Application filed by Sarnoff Corp filed Critical Sarnoff Corp
Priority to AU12158/01A priority Critical patent/AU1215801A/en
Publication of WO2001029870A1 publication Critical patent/WO2001029870A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/70—Arrangements for deflecting ray or beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/70—Arrangements for deflecting ray or beam
    • H01J29/72—Arrangements for deflecting ray or beam along one straight line or along two perpendicular straight lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/80—Arrangements for controlling the ray or beam after passing the main deflection system, e.g. for post-acceleration or post-concentration, for colour switching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
    • H01J31/128—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digitally controlled display tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/20—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes for displaying images or patterns in two or more colours
    • H01J31/201—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes for displaying images or patterns in two or more colours using a colour-selection electrode
    • H01J31/203—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes for displaying images or patterns in two or more colours using a colour-selection electrode with more than one electron beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/58—Electron beam control inside the vessel
    • H01J2229/582—Electron beam control inside the vessel by electrostatic means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/58—Electron beam control inside the vessel
    • H01J2229/587—Electron beam control inside the vessel between the source and the screen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/88—Coatings

Definitions

  • the present invention relates to a cathode ray tube and, in particular, to a cathode ray tube including a deflection aiding electrostatic field.
  • CRTs cathode ray tubes
  • One or more electron guns positioned in a neck of a funnel-shaped glass bulb of a CRT direct a corresponding number of beams of electrons toward a glass faceplate biased at a high positive potential, e.g., 30 kilovolts (kV).
  • the faceplate usually has a substantially rectangular shape and is generally planar or slightly curved. Together, the glass bulb and faceplate form a sealed enclosure that is evacuated.
  • the electron gun(s) are positioned along an axis that extends through the center of the faceplate and is perpendicular thereto.
  • the electron beam(s) is (are) raster scanned across the faceplate so as to impinge upon a coating or pattern of phosphors on the faceplate that produces light responsive to the intensity of the electron beam, thereby to produce an image thereon.
  • the raster scan is obtained by a deflection yoke including a plurality of electrical coils positioned on the exterior of the funnel-shaped CRT near the neck thereof. Electrical currents driven in first coils of the deflection yoke produce magnetic fields that cause the electron beam(s) to deflect or scan from side to side (i.e. horizontal scan) and currents driven in second coils of the deflection yoke produce magnetic fields that cause the electron beam(s) to scan from top to bottom (i.e. vertical scan).
  • the magnetic deflection forces typically act on the electrons of the beam(s) only in the first few centimeters of their travel immediately after exiting the electron gun(s), and the electrons travel in a straight line trajectory thereafter, i.e through a substantially field-free drift region.
  • the horizontal scan produces hundreds of horizontal lines in the time of each vertical scan to produce the raster- scanned image.
  • U.S. Patent 5,327,044 to Chen entitled “Electron Beam Deflection Lens for CRT” desc ⁇ bes a single-electron-gun monochrome cathode ray tube in which a resistive coating 54 in the tube neck and funnel portion 62a, 62b is biased to a potential less than screen potential and contacts a second coating G4 on the inte ⁇ or of the tube funnel and the screen 48 that is biased at screen potential. Chen is not seen to provide any desc ⁇ ption or suggestion regarding any plural-beam or color CRT.
  • the depth of a CRT i.e. the distance between the faceplate and the rear of the neck, is determined by the maximum angle over which the deflection yoke can bend or deflect the electron beam(s) and the length of the neck extending rearward to contain the electron gun. Greater deflection angles provide reduced CRT depth.
  • Modern magnetically-deflected color (i.e. plural beam) CRTs typically obtain a ⁇ 55° deflection angle, which is referred to as 110° deflection.
  • 110° CRTs for screen diagonal sizes of about 62 cm (about 25 inches) or more are so deep that they are almost always provided in a cabinet that either requires a special stand or must be placed on a floor.
  • a 110° CRT having a faceplate with an about 100 cm (about 40 inch) diagonal measurement and a 16:9 aspect ratio is about 60-65 cm (about 24-26 inches) deep.
  • Practical considerations of increasing power dissipation producing greater temperature ⁇ se in the magnetic deflection yoke and its drive circuits and of the higher cost of a larger, heavier, higher-power yoke and d ⁇ ve circuitry make increasing the maximum deflection angle so as to decrease the depth of the color CRT disadvantageous.
  • a display comp ⁇ ses a tube envelope having a faceplate and a screen electrode on the faceplate biased at a screen potential, a source within the tube envelope of a beam of electrons directed toward the faceplate, a deflection yoke proximate the source of a beam of electrons for magnetically deflecting the beam of electrons and defining a deflection plane, and phosphorescent material disposed on the faceplate for producing light in response to the beam of electrons impinging thereon.
  • First and second electrostatic electrodes inte ⁇ or said tube envelope define a gap therebetween that intersects the deflection plane and is partly disposed on one side thereof and partly to the other side thereof.
  • the first electrode is proximate the source of a beam of electrons and is biased at a potential less than the screen potential
  • the second electrode is between the first electrode and the screen electrode and is biased at the screen potential.
  • FIGURES 1A and IB are cross-sectional schematic diagrams of exemplary cathode ray tubes helpful in understanding the present invention
  • FIGURE 2 is a graphical representation of a measure of deflection energy for a cathode ray tube including the exemplary cathode ray tubes of FIGURES 1A and IB
  • FIGURE 3 is a cross-sectional schematic diagram of a plural beam cathode ray tube in accordance with the present invention
  • FIGURE 6 is a cross-sectional diagram of the yoke deflection region of an alternative embodiment of a cathode ray tube in accordance with the invention.
  • FIGURES 7A - 7D are cross-sectional schematic diagrams showing a method of forming an electrode structure in a cathode ray tube according to the invention.
  • FIGURES 8A and 8B are cross-sectional diagrams of an embodiment of a cathode ray tube according to the invention in a conventional-size CRT enclosure and in a reduced-depth CRT enclosure, respectively;
  • FIGURES 9 and 10 are cross-sectional schematic diagrams illustrating alternative electron gun arrangements useful in relation to the cathode ray tube according to the present invention.
  • a plural-beam cathode ray tube 10 e.g., a color cathode ray tube, includes a faceplate 20, screen electrode 22, tube funnel 40, electron gun 12 tube neck 14 and a deflection yoke 16 similarly to a conventional color cathode ray tube.
  • Deflection yoke 16 produces dynamic scanning magnetic fields that have influence on the electron beams in a deflection region substantially lying between a forward plane 18 at the forward (toward the screen 22) end of the deflection yoke 16 and a rearward plane 19 at the rearward (toward the electron gun
  • Cathode ray tube 10 includes a three beam electron gun 12 in tube neck 14 generally symmet ⁇ cally located substantially at the center of tube funnel 40 to direct three beams of electrons 30 towards faceplate 20 which includes a screen electrode 22 biased at a relatively high positive potential. Faceplate 20 and the forward end of tube funnel 40 are generally rectangular in shape and of similar size and are joined by an annular end plate 48 to form a sealed container that can be evacuated. Deflection yoke 16 surrounds tube neck 14 in the region of its juncture with tube funnel 40 for magnetically deflecting electrons generated by gun 12 as they proceed out of gun 12 and toward faceplate 20 to impinge upon the phosphors 23 thereon.
  • Plural-beam tube 10 further includes conductive coatings in two regions on the inte ⁇ or of tube envelope 40.
  • a first conductive coating 46 in a forward region includes the screen 22 and the tube funnel 40 extending rearward away from the screen 22, and is biased to screen potential.
  • a second conductive coating 44 in a rearward region including at least part of tube neck 14 and the rearward portion of tube funnel 40 is biased at a potential below screen potential and is separated from first conductive coating 46 by an insulating interface or gap 45.
  • the insulating gap 45 is disposed partly forward of the forward deflection plane 18 and partly rearward of the forward deflection plane 18.
  • the glass envelope 40, 48 of a typical glass tube 10 will either closely follow or resemble the shape of a conventional CRT, but may be shorter in depth, and the combination of the conductive coatings 44, 46 and the bias potentials thereon beneficially tends to reduce the power required to d ⁇ ve magnetic deflection yoke 16.
  • Shadow mask 24 is spaced slightly apart from faceplate 20 and is attached thereto near their respective pe ⁇ phe ⁇ es by a shadow mask mounting frame (not visible). Shadow mask 24 has a pattern of apertures through which plural electron beams 30 pass to impinge upon the pattern of color phosphors 23 on the inner surface of faceplate 20 to produce light to reproduce an image or information on faceplate 20 that is visible to a viewer.
  • the conductive coating of screen 22 on the inner surface of faceplate 20 is electrically coupled to shadow mask 24 at the shadow mask mounting frame from which shadow mask 24 receives screen bias potential.
  • an evaporable getter mate ⁇ al such as a barium getter mate ⁇ al, may be mounted to the inner surface of glass bulb 40. The getter mate ⁇ al is positioned so as to not coat any important insulating elements, e.g., the gap 45 isolating conductive coatings 44 and 46 or the insulating supports, if any, for electron gun 12.
  • FIGURES 1 A and IB are cross-sectional diagrams of a plural-beam cathode ray tube 10 relating to the invention in its simplest form. It is noted that unless otherwise specified, such cross-sectional diagrams may be considered to illustrate either the ho ⁇ zontal or the vertical deflection o ⁇ entation because both appear similar in such diagrams.
  • a typical tube for reproducing video images has a faceplate that is as viewed wider in the ho ⁇ zontal direction than it is high in the vertical direction, i.e. is positioned for viewing in a ho ⁇ zontal or so-called "landscape" format, although in certain applications such as dedicated word processing or publishing displays, the faceplate may be positioned for viewing in a vertical or so-called "portrait" format.
  • three beams of electrons produced by electron gun 12 located m tube neck 14 are directed towards faceplate 20 which includes a screen or anode electrode 22 which is biased at a relatively high positive potential and a pattern of three different phosphors 23 that emit three different colors of light in response to electrons impinging thereon to produce a color image.
  • the electrons forming three electron beams 30 produced by electron gun 12 are deflected by magnetic fields produced by deflection yoke 16 to scan across the dimension of faceplate 20, such as in a conventional raster scan.
  • Conductive coating 46 on the inte ⁇ or surface of tube funnel 40 proximate faceplate 22 is biased to the same relatively high positive potential as is screen electrode 22.
  • Conductive coating 44 on the inte ⁇ or surface of tube funnel 40 distal faceplate 20 and proximal tube neck 14 is biased to a positive potential that is less than the potential of screen electrode 22.
  • Ultor of electron gun 12 is also biased to the lesser potential to which conductive coating 44 is biased for avoiding unusual electron-injection effects.
  • yoke 44 and yoke 16 may be utilized to realize either a reduction of yoke power, and therefore a smaller, lighter, less expensive and likely more reliable deflection yoke 16, or a greater deflection angle with the same yoke and yoke power.
  • HSE ho ⁇ zontal stored energy
  • HSE is a parameter useful in evaluating yoke efficiency, and is generally proportionally related to the power required to d ⁇ ve the deflection yoke. HSE is representative because the ho ⁇ zontal scanning is at a much higher frequency than is the vertical scanning (e.g., about 15,575 Hz vs. about 60 Hz.), and also because the ho ⁇ zontal deflection angle is greater than the vertical deflection angle in a typical horizontal format CRT
  • HSE-1A The resulting HSE is designated as HSE-1A and lies along HSE characte ⁇ stic 99 in FIGURE 2 which graphically represents the parameter HSE as a function of the position along the Z axis of gap 45 for deflection to a corner of faceplate 20.
  • the HSE-0 reference level is the HSE for an equivalent geometry mono-potential CRT, i.e. a CRT in which the entire inte ⁇ or surface of tube envelope 40 is at screen potential.
  • the electrons of the electron beams are within the field-free region of conductive coating 46 biased at screen potential and so are at their final oi terminal velocity in the region where deflection occurs, whereby the yoke HSE is less than the HSE-0 reference level, but is only slightly less than HSE-0.
  • the interface or gap 45 between lower-potential coating 44 and screen-potential coating 46 is displaced along the Z axis in the direction toward faceplate 20 and away from tube neck 14 and electron gun 12 so as to be forward of the forward deflection plane 18.
  • the resulting HSE is designated as HSE- IB along HSE characte ⁇ stic 99 in FIGURE 2.
  • the electrons of the electron beams are within the elect ⁇ c field region of conductive coating 44 biased at a potential well below screen potential and so are moving at well below terminal velocity in the region where deflection occurs, whereby the yoke may be either less effective or more effective than is the case for the HSE-0 reference level for an equivalent geometry mono-potential CRT.
  • gap 45 happens to be too far forward towards faceplate 20 and so the yoke HSE-1B is slightly higher than the HSE-0 level.
  • HSE decreases and exhibits a minimum value HSE-1, so that there is a position of gap 45 along the Z axis direction of tube 10 at which the required yoke effort HSE represented by HSE characte ⁇ stic 99 tends to be minimized or deflection yoke 16 tends to be optimal
  • HSE characte ⁇ stic 99 for a particular size and geometry tube may be calculated using conventional CRT analysis including but not limited to computer simulation.
  • deflection yoke 16 produces a certain amount of pincushion whereby deflection to either the ⁇ ght or left edge locations of screen 22 on faceplate 20 (i.e , the 3:00 and 9:00 o'clock positions) require the highest HSE of any beam landing location, and deflection to the corners (top or bottom) of screen 22 on faceplate 20 (I e the about 2O0, 4:00, 8:00 and 10:00 positions) requires the lowest HSE for a beam landing location on the pe ⁇ phery of screen 22. As a result, there are different positions of gap 45 that are at the minimum of the characte ⁇ stic 99 for different beam landing locations.
  • the shape of gap 45 defining the boundary between the relatively lower potential region of conductive coating 44 and the relative higher potential of conductive coating 46 not be in a single plane perpendicular to the Z axis, but be shaped so as to be in the most desirable position in the Z axis direction for deflection to the side edges of screen 22 which require the highest HSE.
  • the field produced by conductive coating 44 should extend towards screen 22 and so the location of gap 45 is preferably closest to screen 22, and is forward of the forward deflection plane 18, for affecting deflection of the three electron beams 30 to the side edges of faceplate 20 (i.e. to the 3:00 and 9:00 o'clock locations).
  • gap 45 could be another shape such as a "dog-bone” shape. As used herein with respect to the gap 45 between conductive coatings 44, 46,
  • the relationship and effects of the electrostatic fields desc ⁇ bed above with a non-Z-planar interface therebetween cooperate in a tube 10 that can be shorter in depth than a conventional plural-beam CRT and yet operates at a comparable deflection yoke power level or that can employ a conventional CRT funnel and faceplate and yet operate with a smaller, more efficient deflection yoke, as may be desirable and convenient.
  • the particular bias potentials are selected to obtain, for example, a suitable balance of reduced tube depth and reasonable yoke power in consideration of the effects of each of the bias potentials.
  • bias potential V 44 of the ultor of gun 12 of a particular physical-size tube 10 is increased, the required deflection power of yoke 16 tends to increase, indicating that the V 44 bias potential should be selected in conjunction with selection of the location of gap 45.
  • Bias potentials V 22 and V 44 should be kept below the potential at which X-rays that could penetrate the envelope of tube 10 could be generated, i.e. below about 35 kV.
  • Suitable bias potentials may be applied via one or more standard high-voltage feed- through connections or "buttons" penetrating the glass wall of tube funnel 40.
  • FIGURE 5 is a detail cross-sectional schematic diagram illustrating the region of the gap 45 between the conductive electrodes 44, 46 of the exemplary plural-beam cathode ray tube 10 of FIGURES 3 and 4. While gap 45 may simply be a space between conductive coatings 44 and 46, such space of exposed dielect ⁇ c mate ⁇ al, i.e., the glass of tube funnel 40, may accumulate charge that may distort or otherwise adversely affect the desired electrostatic fields.
  • Gap 45 is shielded by a conductive shield 50 that is elect ⁇ cally connected to one of conductive coatings 44, 46 to block electrons from reaching the dielect ⁇ c mate ⁇ al of tube funnel 40
  • Shield 50 preferably substantially covers gap 45 in that there is no clear or unobstructed straight-line path between the surface of tube funnel 40 exposed in gap 45 and screen 22.
  • conductive shield 50 is a sheet metal structure that is held in position against conductive coating 44 by a suitable adhesive or glass f ⁇ t, or by mechanical clips, glass tabs and other features on the inte ⁇ or surface of funnel 40, or by other suitable means.
  • Metal shield 50 is typically formed of sheet metal such as steel, stainless steel, Invar or Kovar alloy or other nickel-iron alloy, titanium, and the like.
  • gap 45 may be filled with a high-resistivity mate ⁇ al so as to avoid charge build up or by a resistive mate ⁇ al for setting the bias potential on conductive coating 44, such as by resistive voltage division of the screen bias potential on conductive coating 46.
  • Plural-beam tube 10 according to the invention is also advantageous because it
  • generally rectangular shape or “substantially rectangular” refers to a shape somewhat reflective of the shape of faceplate 20 and or the cross- section of tube envelope 40 when viewed in a direction along Z axis 13.
  • a generally rectangular shape includes rectangles and squares, and rectangles and squares having rounded corners and/or concave and/or convex sides, so as to be suggestive of or be racetrack shapes, oval shapes, elliptical shapes and the like.
  • Electrodes 44, 46 may be oval or even almost circular in cross-section, particularly where the cross-section of tube envelope 40 is of such shape, as is often the case at the rearward portions thereof, such as those proximate tube neck 14 and yoke 16
  • FIGURE 6 is a cross-sectional diagram of the yoke deflection region of an alternative embodiment of a plural-beam cathode iay tube 10' in accordance with the invention in which electrode 46 of tube 10 is replaced by an alternative electrode 46' compnsing a plurality of electrodes each having a particular value of bias potential applied thereto
  • Electrode 46' includes, for example, a main conductive coating electrode 46 and three generally narrow conductive coating electrodes 46a, 46b, and 46c, spaced apart along a section of tube funnel 40 at gap 45 forward of gun 12, tube neck 14 and magnetic deflection yoke 16
  • Plural electron beams 30 exit gun 12 directed towards faceplate 20 (not visible) and are magnetically deflected by an angle , typically up to an angle of ⁇ 55° with respect to Z axis 13 with a conventional yoke 16 for a 110° tube
  • electrode 46 tends to either increases the efficiency of deflection yoke 16 or facilitate deflection of the plural electron beams 30 beyond the deflection that would otherwise be produced by deflection yoke 16
  • the electrodes 46a - 46c are preferably biased at different relatively high positive potentials intermediate the screen potential on conductive coating 46 and the bias potential on conductive coating 44 so as to more precisely shape the potential characte ⁇ stic in the region of gap 45 while not accelerating the electrons oi electron beam 30 towards faceplate 20 as quickly as does the screen potential
  • Each of electrodes 46a - 46c is preferably a ⁇ ng electrode proximate tube funnel 40 and typically surrounding Z axis 13 along which is electron gun 12
  • Typical bias potentials for electrodes 46a - 46c are, for example, 19 kV, 23 kV, and 27 kV, respectively, with gun 12 and electrode 44 biased to about 15 kV and screen electrode
  • 46a-46c are preferably a deposited metal such as aluminum, graphite, carbon or iron oxide.
  • a vacuum-compatible resistive voltage divider can be employed within the vacuum cavity formed by tube funnel 40 and faceplate 20, and located in a position shielded from electron gun 12.
  • One form of suitable resistive voltage divider may be provided by high-resistivity mate ⁇ al on the inte ⁇ or surface of glass tube envelope 40, such as by spraying or otherwise applying such coating mate ⁇ al thereto, such as in the gaps 45 between coatings 44, 46, 46a- 46c.
  • Suitable coating materials include, for example, ruthenium oxide, and preferabl ⁇ exhibit a resistance is in the range of 10 8 to 10 10 ohms.
  • the high-resistivity coating is in electrical contact with the metal electrodes 44, 46, and 46a-46c for applying bias potential thereto.
  • the thickness and/or resistivity of such coating need not be uniform, but may be varied to obtain the desired bias potential profile. Alternatively, and beneficially, so varying such resistive coating may be utilized for controllably shaping the profile of the bias potential over the region of gap 45 on the inte ⁇ or surface of tube envelope 40.
  • 46, and/or 46a-46c may be simplified and the number of conductive feedthroughs penetrating tube envelope 40 may be reduced.
  • high-resistivity coating may be applied in the gaps between electrodes, such as electrodes 44, 46, 48 to prevent the build up of charge due to electrons impinging thereat.
  • a mold 80 has an outer surface 82 that defines the shape of the inner surface of the funnel-shaped glass bulb 40' of a cathode ray tube 10 and has raised patterns 84a, 84b credit 84c thereon defining the reverse of the size and shape of the metal st ⁇ ps 46a, 46b, 46c, as shown in FIGURE 7A.
  • glass bulb 40' Upon removal from mold 80, glass bulb 40' has a pattern of grooves 86a, 86b, 86c in the inner surface thereof of the size and shape of the desired metal stripes 46a, 46b, 46c, as shown in FIGURE 7B.
  • metal such as aluminum is deposited on the inner surface of glass bulb 40' sufficient to fill grooves 86a, 86b, 86c, as shown in FIGURE 7C.
  • the metal 88 is removed, such as by polishing or other abrasive or removal method, to leave metal strips 46a, 46b, 46c in grooves 86a, 86b, 86c, respectively, of glass bulb 40, with gaps 45 therebetween, as shown in FIGURE 7D.
  • Conductive feedthroughs 90 provide external connection to metal st ⁇ p electrodes 46a, 46b, 46c through glass bulb 40'.
  • high resistivity mate ⁇ al may be applied as a coating in the gaps 92a, 92b, between electrodes 46a, 46b, 46c.
  • FIGURES 8A and 8B are cross-sectional diagrams of an embodiment of plural-beam cathode ray tube 110 according to the invention in a conventional CRT glass tube envelope 140' and in a reduced-depth CRT envelope 140, respectively, both of which operate in like manner.
  • Neck electrode 144 located proximate to and surrounding neck 114 of cathode ray tube 110 is biased to a potential less than the screen potential to which screen electrode 122 is biased.
  • Electrode 146 which is separated from electrode 144 by gap 145, is biased at screen potential, such as by contacting screen electrode 122 Gap 45 may be either insulating or resistive as when bridged by a high-resistivity coating.
  • Electrodes 144 and 146 are preferably of metal on the inte ⁇ or surface of tube bulb 140, 140' such as by a spray or deposition of aluminum, graphite, carbon or iron oxide.
  • An advantage of the bi-potential tube arrangement is that by a relatively simple modification of the conventional CRT by adding neck electrode 144 and a potential feedthrough therefor and insulating gap 145, existing glass tube bulbs 140' and processing may be utilized in making cathode ray tubes having performance advantages. This is of particular benefit to the makers of computer monitor tubes, projection tubes, color television tubes and the like Alternatively, the depth of tube envelope 140 may be reduced as a result of the increased deflection produced by yoke 116 in cooperation with the electric field of neck electrode 144.
  • FIGURES 9 and 10 are cross-sectional schematic diagrams illustrating alternative electron gun arcangements useful in relation to the plural-beam cathode ray tube 10 according to the invention.
  • the spot size and convergence of the plural electron beams 30 is controlled by the particular electron gun and the convergence of the desired yoke 16.
  • the electrostatic lens in tube funnel 40 formed by conductive coatings 44, 46 are wide open, albeit a weak lens, and has no individual apertures for any of the three individual beams as could provide focusing and convergence of the three beams.
  • Beams entering this open electrostatic lens 44, 46 from electron gun 12 will achieve focus and convergence if they emanate from electron gun 12 as if they originated at the same point in space, i.e., the same point within electron gun 12.
  • electron beams 30R, 30G, 30B appear to have originated at common point 12-C within electron gun 12 even though they originate as parallel beams from three in-line electron sources 12R, 12G, 12B, respectively.
  • Such electron gun 12 in conjunction with an anastigmatic deflection yoke 16 will effectively produce electron beams 30R, 30G, 30B that have a high degree of self convergence across the area of screen 22 and that are also in focus.
  • Asymmetries, if any, between the two outer beams 30R, 30B may be reduced or compensated by applying measured amounts of higher-order harmonics of the yoke drive signal to anastigmatic deflection yoke 16.
  • deflection yoke 16 is a non-self-converging deflection yoke similar to the yokes utilized in conventional television receivers. Yoke 16 may be shorter in the Z-axis direction than a conventional yoke where the CRT 10 with which it is employed is of reduced depth (reduced Z-axis dimension).
  • the video signals applied to the electron gun cathodes to modulate each beam of electrons 30R, 30G, 30B may be processed through a one- dimensional or a two-dimensional frame store so as to be delayed an appropriate time as a function of the position in the image, i.e. the position on the raster-scanned screen.
  • the common electrostatic lens 44, 46 will produce over-focused beams 30R, 30G, 30B as illustrated in FIGURE 10.
  • electron gun 12 preferably is arranged to produce the best and smallest spot for each of electron beams 30R, 30G, 30B, and preferably includes approp ⁇ ate dynamic astigmatism g ⁇ ds to maintain spot size as the electron beams 30R, 30G, 30B are deflected across screen 22 by deflection yoke 16.
  • convergence is con-ected either (a) by processing the red, green, blue (R, G, B) video signals, as a function of their X (ho ⁇ zontal) position on screen 22 or of their Y (vertical) position on screen 22, or both, or (b) by delaying the video signals approp ⁇ ately where the three electron beams 30R, 30G, 30B all travel along the same trajectory across screen 22, l e as where deflection yoke 16 and/or the geometry of conductive coatings 44, 46 are specifically arranged for such result.
  • auxiliary or supplemental magnetic deflection fields such as by including auxiliary or supplemental windings in deflection yoke 16 and/or applying tailored dynamic drive signals that vary as a function of beam position on the area of screen 22 thereto
  • tailored dynamic drive signals that vary as a function of beam position on the area of screen 22 thereto
  • the combination of developing dynamic magnetic fields in deflection yoke 16 may be provided either by providing auxiliary windings or by providing dynamic electromagnetic d ⁇ ve signals, or both.
  • providing a dynamic magnetic field may be employed in conjunction with also providing dynamic elect ⁇ c fields such as by applying dynamic elect ⁇ cal signals to various g ⁇ ds of electron gun 12.
  • the conductive coatings or electrodes on the surface of the tube envelope, such as a faceplate 20, 120 and tube envelope 40, 140 are preferably a sprayed, sublimated, spin coated or other deposition or application of graphite or carbon-based mate ⁇ als, iron oxide, aluminum or aluminum oxide or other suitable conductive mate ⁇ al
  • shielding structures such as shield structure 50 and the clips and supports for shadow mask 24, such structures are preferably formed of a suitable metal such as a titanium, Invar alloy, steel, stainless steel, or other suitable metal and may be bonded to tube envelope 40 or embedded into a glass feature thereof for mechanical support
  • the shadow mask having a pattern of apertures corresponding to the pattern of color phosphors desc ⁇ bed herein may be a shadow mask, a focus mask or any other patterned structure through which electrons pass to impinge upon the color phosphors
  • a higher efficiency shadow mask is available, such as a shadow mask that enables a larger proportion of the electrons of electron beam to pass through the apertures thereof, such high-efficiency shadow mask could be employed in cathode ray tubes of the present invention, thereby resulting in one or more of increased b ⁇ ghtness, reduced spot size or reduced gun diameter (and the benefit of increased deflection angle or reduced yoke power associated therewith)
  • Bias potentials developed by voltage dividers may be developed by resistive voltage dividers formed of discrete resistors, blocks of high-resistivity matenal, coatings of high-resistivity material and other suitable voltage dividers, whether internal or external to tube funnel 40 WHAT IS CLAIMED IS:
  • a plural-beam tube comprising: a tube envelope having a faceplate and a screen electrode on the faceplate adapted to be biased at a screen potential; a source of at least two beams of electrons directed toward said faceplate, wherein said source is adapted for magnetic deflection of said at least two beams of electrons; phosphorescent material disposed on said faceplate for producing light in response to the at least two beams of electrons impinging thereon; and at least first and second electrostatic electrodes on an interior surface of said tube envelope and defining a non-Z-planar gap therebetween, wherein said first electrode is proximate said source and adapted to be biased at a potential less than the screen potential, and wherein said second electrode is between said first electrode and said screen electrode and is adapted to be biased at the screen potential.
  • non-Z-planar gap is one of elongated, substantially elliptical, oval, racetrack-shaped, and substantially rectangular, when viewed from said faceplate.

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  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)

Abstract

La présente invention concerne un tube cathodique (10) à plusieurs faisceaux. Ce tube comprend un canon électronique (12) dirigeant des électrons vers une plaque (20) pourvue d'une électrode polarisée à un potentiel d'écran. Le faisceau d'électrons est dévié de manière magnétique pour balayer la plaque et venir frapper sur un motif de luminophores et produire une lumière de couleurs différentes représentant une image. Un premier revêtement conducteur (44) près du col (14) est polarisé à une valeur inférieure au potentiel d'écran, et un deuxième revêtement conducteur (46), entre l'électrode de col et la plaque, est polarisée à un potentiel d'écran. Un espace (45) compris entre les premier et deuxième revêtements varie en distance par rapport à la plaque de manière à ne pas être plan dans le sens Z. Cet espace non plan dans le sens Z se situe, de préférence, partiellement dans la zone dans laquelle les électrons sont déviés par le bloc de bobinage magnétique (16) et partiellement plus près de la plaque que de la zone de déviation.
PCT/US2000/028927 1999-10-21 2000-10-19 Tube cathodique economiseur d'espace a electrode a double potentiel Ceased WO2001029870A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU12158/01A AU1215801A (en) 1999-10-21 2000-10-19 Bi-potential electrode space-saving cathode ray tube

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US16065499P 1999-10-21 1999-10-21
US60/160,654 1999-10-21
US55879900A 2000-04-26 2000-04-26
US09/559,809 US6541902B1 (en) 1999-04-30 2000-04-26 Space-saving cathode ray tube
US09/559,809 2000-04-26
US09/558,799 2000-04-26

Publications (1)

Publication Number Publication Date
WO2001029870A1 true WO2001029870A1 (fr) 2001-04-26

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WO (1) WO2001029870A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9932409B2 (en) * 2013-07-19 2018-04-03 Vib Vzw Targeted modified IL-1 family members

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB652267A (en) * 1947-12-30 1951-04-18 Gen Electric Co Ltd Improvements in or relating to cathode ray tubes and like devices
US3185879A (en) * 1960-03-17 1965-05-25 Rca Corp Cathode ray tube having deflection enhancement means
DE4220964A1 (de) * 1991-06-27 1993-01-07 Mitsubishi Electric Corp Kathodenstrahlroehre
US5327044A (en) * 1992-04-27 1994-07-05 Chunghwa Picture Tubes, Ltd. Electron beam deflection lens for CRT
WO2000067286A1 (fr) * 1999-04-30 2000-11-09 Sarnoff Corporation Tube cathodique de faible encombrement a deviation amplifiee par voie electrostatique
WO2000067288A1 (fr) * 1999-04-30 2000-11-09 Sarnoff Corporation Tube cathodique economisant l'espace
WO2000067287A1 (fr) * 1999-04-30 2000-11-09 Sarnoff Corporation Tube cathodique asymetrique, a gradients de potentiel, d'encombrement reduit

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB652267A (en) * 1947-12-30 1951-04-18 Gen Electric Co Ltd Improvements in or relating to cathode ray tubes and like devices
US3185879A (en) * 1960-03-17 1965-05-25 Rca Corp Cathode ray tube having deflection enhancement means
DE4220964A1 (de) * 1991-06-27 1993-01-07 Mitsubishi Electric Corp Kathodenstrahlroehre
US5327044A (en) * 1992-04-27 1994-07-05 Chunghwa Picture Tubes, Ltd. Electron beam deflection lens for CRT
WO2000067286A1 (fr) * 1999-04-30 2000-11-09 Sarnoff Corporation Tube cathodique de faible encombrement a deviation amplifiee par voie electrostatique
WO2000067288A1 (fr) * 1999-04-30 2000-11-09 Sarnoff Corporation Tube cathodique economisant l'espace
WO2000067287A1 (fr) * 1999-04-30 2000-11-09 Sarnoff Corporation Tube cathodique asymetrique, a gradients de potentiel, d'encombrement reduit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9932409B2 (en) * 2013-07-19 2018-04-03 Vib Vzw Targeted modified IL-1 family members

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