EP0388901B1 - Farbkathodenstrahlröhre - Google Patents

Farbkathodenstrahlröhre Download PDF

Info

Publication number
EP0388901B1
EP0388901B1 EP90105263A EP90105263A EP0388901B1 EP 0388901 B1 EP0388901 B1 EP 0388901B1 EP 90105263 A EP90105263 A EP 90105263A EP 90105263 A EP90105263 A EP 90105263A EP 0388901 B1 EP0388901 B1 EP 0388901B1
Authority
EP
European Patent Office
Prior art keywords
electron
grid
electron beams
beams
horizontal
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.)
Expired - Lifetime
Application number
EP90105263A
Other languages
English (en)
French (fr)
Other versions
EP0388901A3 (de
EP0388901A2 (de
Inventor
Taketoshi C/O Intellectual Property Div. Shimoma
Eiji C/O Intellectual Property Div. Kamohara
Shigeru C/O Intellectual Property Div. Sugawara
Jiro C/O Intellectual Property Div. Shimokobe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba 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
Application filed by Toshiba Corp filed Critical Toshiba Corp
Publication of EP0388901A2 publication Critical patent/EP0388901A2/de
Publication of EP0388901A3 publication Critical patent/EP0388901A3/de
Application granted granted Critical
Publication of EP0388901B1 publication Critical patent/EP0388901B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01J29/48—Electron guns
    • H01J29/50—Electron guns two or more guns in a single vacuum space, e.g. for plural-ray tube
    • 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
    • H01J29/48—Electron guns
    • H01J29/50—Electron guns two or more guns in a single vacuum space, e.g. for plural-ray tube
    • H01J29/503—Three or more guns, the axes of which lay in a common plane
    • 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
    • H01J29/48—Electron guns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/48—Electron guns
    • H01J2229/4834—Electrical arrangements coupled to electrodes, e.g. potentials
    • H01J2229/4837—Electrical arrangements coupled to electrodes, e.g. potentials characterised by the potentials applied
    • H01J2229/4841—Dynamic potentials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/48—Electron guns
    • H01J2229/4844—Electron guns characterised by beam passing apertures or combinations
    • H01J2229/4848—Aperture shape as viewed along beam axis
    • H01J2229/4858—Aperture shape as viewed along beam axis parallelogram
    • H01J2229/4865—Aperture shape as viewed along beam axis parallelogram rectangle
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/48—Electron guns
    • H01J2229/4844—Electron guns characterised by beam passing apertures or combinations
    • H01J2229/4848—Aperture shape as viewed along beam axis
    • H01J2229/4872—Aperture shape as viewed along beam axis circular
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/48—Electron guns
    • H01J2229/4844—Electron guns characterised by beam passing apertures or combinations
    • H01J2229/4848—Aperture shape as viewed along beam axis
    • H01J2229/4896—Aperture shape as viewed along beam axis complex and not provided for

Definitions

  • the present invention relates to a color cathode-ray tube apparatus and, more particularly, an electron gun assembly for use in a color cathode-ray tube apparatus, which dynamically focuses electron beams, thereby forming a high-resolution image on the phosphor screen of the color cathode-ray tube apparatus.
  • Fig. 1 is a cross-sectional view of a color cathode-ray tube apparatus of the most common type.
  • the color cathode-ray tube apparatus comprises a faceplate 3, a funnel 4, a neck 5, an electron gun assembly 6, a deflection unit 7, and a shadow mask 9.
  • the faceplate 3 has an edge portion 3a.
  • a screen 2 is formed on the inner surface of the faceplate 3.
  • the funnel 4 connects the edge portion 3a of the faceplate 3 to the neck 5.
  • the electron gun assembly 6 is located within the neck 5.
  • the deflection unit 7 is shaped like a ring, surrounding the junction of the funnel 4 and the neck 5. The unit 7 is designed to deflect the electron beams emitted by the electron gun assembly 6.
  • the shadow mask 8 is held in the faceplate 3 and opposes the screen 2, spaced apart therefrom by a predetermined distance.
  • the mask 9 has a number of apertures 8 for guiding the electron beams onto the screen 2.
  • the color cathode-ray tube apparatus further comprises an inner conductive layer 10 and an anode terminal (not shown).
  • the layer 10 is coated uniformly on the inner surface of the funnel 4 and also on a part of the inner surface of the neck 5.
  • the anode terminal (not shown) is mounted on a part of the inner surface of the funnel 4.
  • Red phosphor, green phosphor, and blue phosphor are coated on the screen 2 in the form of stripes or dots.
  • the electron gun assembly 6 emits three electron beams BR, BG, and BB.
  • the beams BR, BG, and BB are deflected by the deflection unit 7, guided by the shadow mask 9, and applied onto the phosphor stripes or dots.
  • the red phosphor stripes or dots emit red light
  • the green phosphor stripes or dots emit green light
  • the blue phosphor stripes or dots emit blue light.
  • the electron gun assembly 6 has a beam-forming section GE and a beam-processing section ML.
  • the section GE generates three parallel electron beams BR, BG, and BB in so-called "in-line alignment," and accelerates and controls these beams.
  • the beam-processing section ML focuses and converges the three electron beams emitted from the beam-forming section GE.
  • the electron beams BR, BG, and BB emitted from the electron gun assembly 6 are deflected by means of the deflection unit 7, guided by the shadow mask 8, and applied onto the screen 2. Hence, the electron beams scan the screen 2, forming rasters on the screen 2.
  • the deflection unit 7 has a horizontal deflection coil and a vertical deflection coil.
  • the horizontal deflection coil generates a horizontal-defection magnetic field for deflecting the electron beams in the horizontal direction.
  • the vertical deflection coil generates a vertical-defection magnetic field for deflecting the electron beams in the vertical direction.
  • the so-called "convergence-free system” is used in the conventional cathode-ray tube apparatus.
  • the horizontal-deflection magnetic field is formed into a pincushion-shape
  • the vertical-deflection magnetic field is formed into a barrel-shape. The pincushion magnetic field and the barrel magnetic field act, in concert, on the three electron beams such that the beams are correctly converged on the target phosphor stripes or dots, respectively.
  • a magnetic field which is considered to be uniform in its intensity distribution, includes a small pincushion component or a small barrel component.
  • Fig. 2A schematically shows a magnetic field including a pincushion component.
  • An electron directed to the peripheral portion of the screen 2 is subjected to a relatively prominent deflection aberration as the beam passes through this magnetic field. Consequently, when the beam lands on the peripheral portion of the screen 2, it forms a beam spot which is distorted as is shown in Fig. 2B.
  • the distorted beam spot consists of a horizontally elongated core having high luminance and halos having low luminance, one extending upward from the core and the other extending downward from the core. The larger the cathode-ray tube apparatus, or the more the beam is deflected, the more the beam spot is distorted.
  • This distortion of the beam spot is produced due to a over-focus of the electron beam in the vertical plane.
  • a method of reducing or eliminating the deflection aberration, i.e., the cause of the distortion of the beam spot, is disclosed in Television Technology, Vol. 36, pp. 41-55, 1988. This method is characterized in that a quadruple lens is incorporated into an electron gun assembly, and is driven to emit an electron beam having a cross section whose upper and lower portions are more intense than the right and left portions.
  • an electron beam will have an elliptical cross section extending in the vertical direction, and will be subjected to a more prominent aberration.
  • the power of the electron lens must be changed greatly.
  • the more the power of the lens is varied the greater the changes in the voltage for achieving dynamic focusing of the beam, and, hence, the greater circuit load the cathode ray tube apparatus required.
  • the electron beam is excessively diverged in the vertical plane and the electron beam is excessively focused in the horizontal direction. It is therefore necessary to add to the lens some elements for correcting this over-focusing of the electron beam, which would render the lens more complex in structure.
  • the circuit for controlling the electron gun assembly needs to be complex inevitably.
  • EP-A-O 231 964 and EP-A-O 315 269 disclose similar colour ray tube apparatus in which a dynamic focus system comprising a quadruple lens is used:
  • Document EP-A-0 231 964 describes a colour display tube comprising an electron gun of the in-line type.
  • the electron gun comprises a main lens which is constituted by a first focussing electrode and a second focussing electrode.
  • the first focussing electrode comprises sub-electrodes placed at a distance from each other between which an auxiliary electrode constituting an astigmatic element is positioned.
  • the auxiliary electrode is connected during operation to means for applying a constant voltage, whilst at least the sub-electrode forming part of the main lens is connected during operation to means for applying a control voltage.
  • the control voltage may be a static voltage or a dynamically varying voltage, for example, a parabolic voltage which is in synchronism with the line deflection.
  • document EP-A-0 315 269 falling within the terms of Article 54(3) EPC describes a colour display tube having an in-line electron gun and a deflection system.
  • the deflection system generates deflection fields having an astigmatic character, such that in an usual electron gun overconvergence of the electron beams would occur on a display window.
  • the electron gun is changed such that this overconvergence compensated by an underconvergence generated in the electron gun.
  • the horizontal spot enlargement factor is reduced by the less astigmatic character of the deflection fields.
  • Japanese Laid Open Patent Application No. 60-25140 corresponding to EP-A-0 120 478 discloses a cathode-ray tube apparatus, wherein electron beams are guided to cross twice the axis of the electron gun assembly, thereby to achieve a sufficient resolution even if the beam current is comparatively small.
  • the gun assembly used in this apparatus comprises a three-electrode unit including a first grid G1 (i.e., the control electrode) and a second grid G2 (i.e., the shield electrode), a main lens electrode for forming a main electron lens, and an auxiliary electrode G2s.
  • the electrode G2s is interposed between the three-electrode unit and the main-lens electrode, and is applied with a voltage which is lower than the voltage applied to the second grid G2 and changes in accordance with the desired deflection angle of the electron beam.
  • the electron beam crosses the axis of the assembly twice until it reaches the main lens electrode, and its peripheral portion is trimmed by a trimming electrode as the beam travels from the main lens electrode to the phosphor screen.
  • the beam forms but a distorted spot on the phosphor screen due to the deflection aberration, though the image resolution is sufficiently high if the beam current is relatively small. This is because the beam is anisotropically distorted by the deflection magnetic field, and the anisotropic distortion cannot be eliminated since the beam crosses the axis of the gun assembly two times while traveling from the cathode to the main lens electrode.
  • the shape of the second cross-over is changed in the horizontal or vertical plane, due to the auxiliary electrode G2s which are located between the cathode and the third grid G3, or within the beam-forming section of the gun assembly.
  • the deflection aberration cannot be either reduced or eliminated in the cathode-ray tube, wherein self-convergence deflection magnetic fields are generated. Rather, the deflection aberration increases, and the beam will form an even more distorted spot on the phosphor screen.
  • the electron lens is located in the beam-forming section of the gun assembly, in order to make the beam cross the axis of the gun assembly for the second time.
  • This electron lens comprises four thin electrodes. These electrodes are located so close to one another that their potential affect mutually to a degree which depends on the shapes of the electrodes and also those of the openings made in the electrodes. Consequently, the characteristics of the electron lens fluctuate. Due to the fluctuation of its characteristics, the lens can hardly focus an electron beam sufficiently in the vertical direction only. Rather, this quadruple lens may focus an electron beam more in the horizontal direction than in the vertical direction.
  • the object of the present invention is to provide a colour cathode-ray tube apparatus wherein, although electron beams are subjected to deflection aberration, they are focused such that beam spots distorted as little as possible are formed on the phosphor screen, thereby forming a high-quality image on the entire phosphor screen.
  • the present invention provides a colour cathode ray tube apparatus as specified in claim 1.
  • Fig. 3 is a longitudinal sectional view of a color cathode ray-tube apparatus according to the invention, taken along X-Z plane, i.e., the horizontal plane.
  • Fig.4 is also a longitudinal sectional view of the electron gun assembly incorporated in the apparatus, taken along Y-Z plane, i.e., the vertical plane.
  • an electron gun assembly 100 of in-line type is incorporated in the neck 5 of the color cathode-ray tube apparatus.
  • the assembly 100 comprises an insulated support rod MFG, three cathodes K, a first grid G1, a second grid G2, a third grid G3, a fourth grid G4, a fifth grid G5, an auxiliary grid G56, a sixth grid G6, a seventh grid G7, an eighth grid G8, and a ninth grid G9.
  • the nine grids and the auxiliary grid are supported by the support rod MFG, and are arranged in a line, from the cathodes K toward the screen SCN in the order they are mentioned.
  • a bulb spacer BS is mounted on the ninth grid G9 and contacts the inner surface of the neck 5, thus holding the grid G9 in place.
  • the electron gun assembly 100 is fixed to the neck 5 by means of stem pins STP.
  • the cathodes K contains a heater H each, and emits three electron beams BR, BG, and BB when the heaters H generate heat.
  • the first grid G1 and the second grid G2 have three, relatively small holes each. The three holes of either grid guide the electron beams BR, BG, and BB.
  • the third grid G3 is a hollow, thin member made of two parallel plates which are spaced apart for a short distance and connected together at both ends. That plate of the grid G3, which opposes the second grid G2, has three beam-guiding holes, which are larger than those of the second grid G2.
  • the cathodes K, the first grid G1, the second grid G2, and the third grid G3 constitute an electron beam-forming section GE for controlling and accelerating electron beams.
  • That plate of the third grid G3, which opposes the fourth grid G4, has three, relatively large beam-guiding holes 121.
  • the fourth grid G4 is a hollow, thin member made of two parallel plates each having three beam-guiding holes which have the same diameter as the beam-guiding holes 121.
  • the fifth grid G5 is also a hollow, thin member made of two parallel plates. That plate of the fifth grid G5, which opposes the fourth grid G4, has three beam-guiding holes having the same diameter as the holes 121 of the third grid G3. That plate of the fifth grid G5, which opposes the auxiliary grid G56, has one hole 122 for guiding the three electron beams BR, BG, and BB. As is shown in Fig.
  • the beam-guiding hole 122 is elongated in the X direction.
  • the fifth grid G5 has projections PT extending in the Z direction in the electrode structure.
  • the auxiliary grid G56, the sixth grid G6, and the seventh grid G7 have one beam-guiding hole each, which is elongated in the X direction like the hole 122 of the fifth grid G5.
  • the auxiliary grid G5 also has projections PT extending in the Z direction in the electrode structure.
  • the eighth grid G8 is a hollow, thin member made of two parallel plates, both having one beam-guiding hole which is elongated in the X direction.
  • a hollow cylinder LCY 8 is connected to that plate of the grid G8 which opposes the phosphor screen.
  • a electric field control plate ECD is located in the hollow cylinder LCY, dividing the interior of the cylinder LCY into two portions.
  • the plate ECD has three rectangular beam-guiding holes extending in the Y direction, i.e., a center hole 123 and two side holes 124 larger than the center hole 123.
  • Two projections VIS extend in the Z direction from those portions of the plate ECD which are located at the upper end lower edges of either side beam-guiding hole 124.
  • the ninth grid G9 is a large hollow cylindrical electrode LCY 9 which surrounds the eighth grid G8.
  • An electron lens LEL is formed between the eighth grid G8 and the ninth grid G9.
  • the bulb spacer BS is mounted on the front-end portion of the ninth grid G9.
  • the spacer electrically and mechanically contacts a conductive layer 10 coated on the inner periphery of the junction between the funnel 4 and neck 5 of the cathode-ray tube apparatus.
  • a high anode voltage is applied to the ninth grid G9 via the layer 10 and the bulb spacer BS from an anode terminal (not shown) mounted on the funnel 4.
  • Predetermined voltages are applied to all other grids from the external voltage sources PS through the stem pins STP.
  • a deflection yoke 7 is mounted on the junction of the funnel 4 and the neck 5.
  • the yoke 7 comprises a horizontal deflection coil and a vertical deflection coil.
  • the horizontal deflection coil deflects the electron beams BR, BG, and BB emitted from the gun assembly, in the horizontal direction.
  • the vertical deflection coil deflects the beams BR, BG, and BB in the vertical direction.
  • a multi-pole magnet PCM is mounted on the neck 5 and located close to the deflection yoke 7, for adjusting the paths of the electron beams BR, BG, and BB.
  • a cutoff voltage of 150 kV is applied to the cathodes K, and video signals are also supplied to the cathodes K.
  • the first grid G1 is maintained at the ground potential, whereas a voltage of 500 V to 1 kV is applied to the second grid G2.
  • Voltages of 5kV to 10 kV are applied to the grids G3, G5, G6, and G8; a voltage of 0 V to 1 kV is applied to the fourth grid G4; a voltage of 0 V to 3 kV is applied to the auxiliary grid G56; and a voltage of 15 to 20 kV is applied to the seventh grid G7.
  • a voltage of 25 kV to 35 kV which is equivalent to an anode voltage, is applied to the ninth grid G9.
  • FIG. 6A illustrates only the grids of the gun assembly, more particularly showing the arrangement of these grids.
  • Fig. 6B shows the positions which the electron lens assume in the horizontal plane, i.e., the X-Z plane.
  • Fig. 6C shows the positions which the electron lens take in the vertical plane, i.e., the Y-Z plane.
  • Fig. 6D is a perspective view of the system comprised of some of the electron lenses shown in Figs. 6B and 6C.
  • the cathodes K generate electron beams BR, BG, and BB in accordance with a video signals supplied to them. These electron beams are focused by the grids G1 and G2, thereby crossing gun axes ZR, ZG, and ZB at first cross-overs CO1. The beams are focused a little by prefocusing lenses PL formed between the grids G2 and G3, and is supplied to the third grid G3.
  • the electron beams BR, BG, and BB pass through the third grid G3 and focused by unipotential lenses ELS as they pass through the fourth grid G4. They are further focused by a single electron lens LEL, as they pass through the grids G5 to G9.
  • the electron beams BR, BG, and BB thus focused, are deflected by the yoke 7 in both the horizontal direction and the vertical direction and applied to adjacent red, green and blue phosphor stripes or dots formed on the screen SCN.
  • the electron beams BR, BG, and BB scan the phosphor screen SCN, forming a color image thereon.
  • each electron beam has a deflection aberration.
  • the characteristics of the main electron lens LEL are changed to cancel out the deflection aberration, thereby to impart high quality to the color image.
  • the unipotential lenses ELS are defined by the round beam-guiding holes of the fourth grid G4, the beam-guiding holes of that plate of the third grid G3 which opposes the grid G4, and the beam-guiding holes of that plate of the fifth grid G5 which opposes the grid G4.
  • the lenses ELS focus the electron beams BR, BG, and BB, which are travelling from the first cross-over CO1 and passing through the third grid G3, a little in both the horizontal direction and the vertical direction.
  • the elongated beam-guiding hole of the auxiliary grid G56, the elongated beam-guiding hole of that plate of the grid G5 which faces the grid G56, and the elongated beam-guiding hole of that plate of the grid G6 which opposes the grid G56 define a single electron lens VL1.
  • This lens VL1 focuses the electron beams BR, BG, and BB more in the vertical plane, i.e., the Y-Z plane, than in the horizontal plane, i.e., the X-Z plane.
  • the beams cross the gun axes in the vertical plane in the middle portion of the sixth grid G6, thus forming second cross-over CO2.
  • the beams diverge from the second cross-over CO2 toward the seventh grid G7.
  • the elongated beam-guiding hole of the grid G7, the elongated beam-guiding hole of that plate of the grid G6 which opposes the grid G7, and the elongated beam-guiding hole of that plate of the grid G8 which opposes the grid G7 define a single electron lens VL2.
  • This electron lens VL2 focuses the beams a little in the vertical plane and applied to the single electron lens LEL which is defined by the grids G8 and G9.
  • the electron lens LEL focuses the beams BR, BG, and BB in both the horizontal plane and the vertical plane onto the center portion of the phosphor screen SCN. As the electron beams land on the screen SCN, they form small beam spots.
  • the potential of the auxiliary grid G56 is increased as is illustrated in Fig. 7 in accordance the voltage applied to the auxiliary grid G56 from the power source PS.
  • the vertical-focusing power of the cylindrical electron lens VL1 decreases as is indicated by the broken line in Fig. 6C, and the second cross-over CO2 shifts to position CO2(D).
  • the side beams BR and BB are dynamically focused in the same way as the center beam BG.
  • the diameter they have in the deflection start plane decreases from D to Dd.
  • the second cross-over may be formed at a position between the lens VL2 or LEL and the screen to obtain a same advantage.
  • Fig. 6D is a perspective view showing the major electron lens which act on the center beam BG.
  • the electron lens VL1 which is defined by the grids G5, G56, and G6, focuses the beam BG more in the vertical plane than in the horizontal plane.
  • a line-like second cross-over CO2 is formed, where the beam BG crosses the gun axis in front of the electron lens LEL.
  • the lens VL1 is designed to focus three electron beams to the same degree. More specifically, the lens VL1, which is a planar unipotential lens, is formed by the three electrodes identical to the one shown in Fig. 5B, which are incorporated in the grids G5, G56, and G6, respectively.
  • the elongated beam-guiding hole of each electrode consists of one straight portion having a height av and a width aH, and two sector-shaped portions having a height bv and a width bH. Assuming that the three electron beams are spaced apart at intervals sg, the heights av and bv and the widths aH and bH have the following relationships: aH > 2 sg + av bv > 1.5 av bH > av/2
  • the potential of the end portions of each electrode would focus the electron beams in the horizontal plane, and the side electron beams, in particular, would be deflected.
  • the color cathode-ray tube apparatus of this invention needs but a relatively low dynamic-focusing voltage. This means that the circuit for driving the apparatus need not include a high dynamic-focusing voltage source, and can therefore be made at low cost.
  • the lens VL1 of a plane type for forming the cross-over CO2 is formed by the electrode which has one elongated hole 122 for allowing three electron beams to pass therethrough.
  • the electrode G5 may be provided with three elongated holes 123 to form the electron lens, as shown in Fig. 5D.
  • the aperture ratio between a lateral dimension aH to a longitudinal dimension aV of the hole 123 set to be relatively large value or quadruple lens is formed to apply a divergence force to the electron beams in the horizontal plane, as described below, since the electron beams are not focused only in the vertical plane but also in the horizontal plane.
  • the electron beams BR, BG, and BB are focused excessively in the vertical plane, inevitably because of the deflection aberration of the beams, caused by the magnetic field generated by the deflection yoke 7. Nevertheless, this excessive focusing is eliminated.
  • the horizontal-deflection aberration of an electron beam is so small that it need not be reduced or eliminated at all. If necessary, however, the horizontal-deflection aberration can be eliminated.
  • that plate of the grid G5 which opposes the grid G4 may be lengthened, and that plate of the grid G5 which opposes the auxiliary grid G56 is shortened, whereby a quadruple lens is formed between the grid G5 and the auxiliary grid G56.
  • This electron lens has a small beam-focusing power.
  • the voltage of the auxiliary grid G56 is increased to decrease the focusing power of the quadruple lens formed between the grids G5 and G56.
  • the electron beams are focused also in the horizontal plane and weakly focused in the vertical plane relative to that in the horizontal plane or diverged in the vertical plane. Since the quadruple lens is much more sensitive than an lens, its focusing power remains sufficiently great even if the potential of the auxiliary grid G56 fluctuates by several hundred volts. Hence, the electron beams directed to a peripheral portion of the screen SCN are focused in the horizontal plane, a little too much.
  • the cathode-ray tube apparatus has, among other things, the electron lens VL1 for focusing the beams BR, BG, and BB mainly in the vertical plane, thereby forming a second cross-overs CO2 extending in the horizontal direction, and the electron lens LEL for focusing these beams, supplied from the cross-overs CO2, onto the phosphor screen SCN.
  • the lens VL1 does not focus the beams in the horizontal plane, thus forming no cross-overs in the horizontal plane between the lens VL1 and the lens LEL.
  • the vertical-focusing power of the lens VL1 is decreased in proportion to the deflection angle of the beams.
  • the second cross-overs CO2 are thereby shifted toward the electron lens LEL, appropriately focusing the electron beams BR, BG, and BB onto the peripheral portion of the phosphor screen SCN.
  • the electron beams BR, BG, and BB have virtually no deflection aberration in the horizontal direction, or are under-focused in the horizontal plane.
  • the lens VL1 should better be designed to focus the beams at all or slightly over-focus them in the horizontal plane, when its horizontal-focusing power is reduced in proportion to the deflection angle of the electron beams.
  • the lens VL1 should focus the beams to form cross-overs at positions very close to the electron lens LEL.
  • the electron lens VL1 be a lens which focuses beams in the vertical plane only. More specifically, the lens VL1 must have such an electrode as is shown in Fig.
  • the beam-guiding hole 122 consists of a straight portion and two sector-shaped portions 122′, and the electrode has two projections PT extending in the X direction from upper and lower edges of the straight portion of the hole 122.
  • the electrode shown in Fig. 5B focuses the three beams BR, BG, and BB to the same degree in the vertical plane only.
  • the embodiment described above has other electron lenses PL, ELS, and VL2. These lenses are used to adjust the focusing of the beams and to enhance the efficiency of the electron gun assembly, thereby to form small beam spots on the center portion of the phosphor screen SCN.
  • Fig. 8 illustrates a color cathode-ray tube apparatus, which is another embodiment of the invention.
  • the same reference numerals and symbols are used to designate the same components as those shown in Fig. 3.
  • this embodiment is characterized in two respects.
  • the electron gun assembly has no component equivalent to the auxiliary grid G56.
  • the fifth grid G5 is maintained at a low potential of 1 to 3 kV, thus forming an electron lens VL1 between the fifth grid G5 and the six grid G56.
  • This lens VL1 focuses electron beams BR, BG, and BB mainly in the vertical plane.
  • the electron lens system is, after all, the same as that of the first embodiment.
  • the potential of the fifth grid G5, which is relatively low, is increased in proportion to the deflection angle of the electron beams.
  • the vertical-focusing power of the lens VL1 is reduced, and the horizontal-focusing power of the cylindrical unipotential lens ELS, formed by the grids G3, G4, and G5, is increased.
  • the increase in the vertical-focusing power of the lens ELS increases the degree of horizontal focusing of the beams which is insufficient because of the deflection aberration imparted to the beams by the self-converging magnetic field generated by the deflection yoke 7.
  • the electron beams are thereby focused appropriately also in the horizontal plane.
  • Either embodiment described above has an electron gun assembly which has large electron lenses used for focusing three electron beams. Nevertheless, this invention can be applied to a color cathode-ray tube apparatus wherein three identical large electron lenses are used in place of each of such lenses, for focusing the three electron beams, respectively. Moreover, according to the present invention, the electrode shown in Fig. 5B can be replaced by three electrodes, each having an elongated hole, for focusing three electron beams, respectively.
  • the present invention can provide a color cathode-ray tube apparatus, in which three electron beams set in an in-line alignment are focused such that they form a high-quality image on the phosphor screen, despite of the deflection aberration the beams have as they are deflected in the horizontal and vertical directions.
  • the apparatus since it suffices to apply a low dynamic voltage to reduce or eliminate the deflection aberration of the beams, the apparatus needs no drive circuits which includes a high-voltage source and is therefore expensive.
  • the electron lens for reducing or eliminating the deflection aberration of the beams is a cylindrical one, not a quadruple lens, which need not be controlled to adjust its horizontal-focusing power and which is easy to operate and design.

Landscapes

  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)

Claims (7)

  1. Farbkathodenstrahlröhrengerät, mit:
    einer Elektronenkanonenanordnung (100) mit drei Kanonenachsen (ZR, ZG, ZB), die in einer Horizontalebene ausgerichtet sind, zum Fokussieren und Konvergieren-von drei Elektronenstrahlen (BR, BG, BB),
    einer Einrichtung (7) zum Erzeugen von Horizontal- und Vertikalablenkmagnetfeldern, um die drei Elektronenstrahlen (BR, BG, BB), die von der Elektronenkanonenanordnung (100) ausgesandt sind, in einer Horizontalebene und einer Vertikalebene abzulenken, wobei das Horizontalablenkmagnetfeld als ein kissenförmiges Feld erzeugt ist, und
    einem Leuchtstoffschirm (SCN) zum Emittieren von Rot-, Grün- und Blau-Lichtstrahlen, wenn die abgelenkten Elektronenstrahlen darauf auftreffen,
    wobei die Elektronenkanonenanordnung aufweist:
    drei Kathoden (K), die in einer In-Linien-Ausrichtung angeordnet sind, um drei Elektronenstrahlen jeweils längs der drei Kanonenachsen zu emittieren,
    eine Steuerelektrodeneinrichtung (G1, G2), mit drei runden Löchern, um die Elektronenstrahlen, die durch die Kathoden (K) emittiert wurden, zu beschleunigen und zu steuern, und um jeden der drei Elektronenstrahlen zu veranlassen, seine jeweilige Kanonenachse zu kreuzen und dadurch eine punktförmige erste Überkreuzung (CO1) auf jeder der Kanonenachsen zu definieren,
    eine erste Elektronenlinseneinrichtung (ELS, VL1) mit Elektroden (G3, G4, G5), deren jede aus zwei parallelen Platten besteht, die einander gegenüberliegen, wobei die jeweilige Platte auf der Kathodenseite einer derartigen Elektrode drei runde Löcher (121) hat, um jeweils drei Elektronenstrahlen zu leiten, und die jeweilige Platte auf der Leuchtstoffseite ein Loch (122) aufweist, das in der Horizontalrichtung länglich ist, um die Elektronenstrahlen zu leiten, damit sie ihre jeweilige Kanonenachse in der Vertikalebene kreuzen, wodurch eine linienförmige zweite Überkreuzung (CO2) gebildet wird, die sich in der Horizontalebene auf jader der Kanonenachsen erstreckt, wobei eine der Elektroden der ersten Elektronenlinseneinrichtung, die ihre Platte auf der Leuchtstoffschirmseite hat, mit einem Potential beaufschlagt ist, das gemäß der Horizontal- oder Vertikalablenkung der Elektronenstrahlen verändert ist, und wobei die anderen Elektroden der ersten Elektronenlinseneinrichtung auf einem vorbestimmten Potential gehalten sind, um dadurch die linienähnlichen zweiten Überkreuzungen (CO2) auf den Kanonenachsen zu verschieben, und
    eine zweite Elektronenlinseneinrichtung (VL2, LEL) einschließlich Elektroden (G6, G7, G8) zum Fokussieren der Elektronenstrahlen und auch zum Konvergieren der Elektronenstrahlen, während die Strahlen zu dem Leuchtstoffschirm (SCN) verlaufen, wobei
    die zweiten Elektronenlinseneinrichtungen (G6, G7, G8; VL2) ein Durchgangsloch haben, um die drei Elektronenstrahlen zu leiten, die aus den linienähnlichen zweiten Überkreuzungen (CO2) austreten,
    wobei die ersten und zweiten Elektronenlinseneinrichtungen eine Ablenkung und Verzerrung korrigieren, die durch das kissenförmige Feld erzeugt ist.
  2. Farbkathodenstrahlröhrengerät nach Anspruch 1, dadurch gekennzeichnet, daß das längliche Loch der ersten Elektronenlinseneinrichtung einen geraden Teil mit einer vorbestimmten Breite und zwei breite Teile, die kontinuierlich zu dem geraden Teil sind, hat.
  3. Farbkathodenstrahlröhrengerät nach Anspruch 2, dadurch gekennzeichnet, daß das längliche Loch, das in den jeweiligen Platten der ersten Elektronenlinseneinrichtung vorgesehen ist, die folgenden Abmessungsmerkmale hat: aH > 2 sg + av
    Figure imgb0007
     bv > 1,5 av
    Figure imgb0008
     bH > av/2
    Figure imgb0009
        wobei av die Höhe des geraden Teiles ist, aH die Breite hiervon ist, bv die Höhe der breiten Teile ist, bH die Breite hiervon ist, und sg das Intervall ist, unter dem die Elektronenstrahlen an dem länglichen Loch der ersten Elektronenlinseneinrichtung beabstandet sind.
  4. Farbkathodenstrahlröhrengerät nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die erste Elektronenlinseneinrichtung eine Vertikallinsenkraft in der Vertikalebene und eine Horizontallinsenkraft in der Horizontalebene hat, wobei die Vertikallinsenkraft größer als die Horizontallinsenkraft ist.
  5. Farbkathodenstrahlröhrengerät nach Anspruch 1, dadurch gekennzeichnet, daß die Steuerelektrodeneinrichtung erste, zweite und dritte Gitter umfaßt, die jeweils drei runde Löcher haben, die erste Elektronenlinseneinrichtung ein viertes Gitter mit drei runden Löchern, um jeweils die drei Elektronenstrahlen zu leiten, ein fünftes Gitter mit ersten und zweiten Platten mit Abständen dazwischen, wobei die erste Platte drei runde Löcher, um jeweils die drei Elektronenstrahlen zu leiten, hat, und die zweite Platte ein Loch, das länglich in der Horizontalrichtung ist, hat, um die drei Elektronenstrahlen zu leiten, wobei das fünfte Gitter mit einem Potential beaufschlagt ist, das gemäß der Horizontal- oder Vertikalablenkung der Elektronenstrahlen verändert ist und das vierte Gitter und ein sechstes Gitter auf einem vorbestimmten Potential gehalten sind, um dadurch die linienähnlichen zweiten Überkreuzungen auf den Kanonenachsen zu verschieben, umfaßt.
  6. Farbkathodenstrahlröhrengerät nach Anspruch 5, dadurch gekennzeichnet, daß das längliche Loch des fünften Gitters einen geraden Teil mit einer vorbestimmten Breite und zweite breite Teile, die kontinuierlich zu dem geraden Teil sind, hat.
  7. Farbkathodenstrahlröhrengerät nach Anspruch 1, gekennzeichnet durch ein Hilfsgitter (G56), das zwischen der ersten und zweiten Elektronenlinseneinrichtung vorgesehen ist.
EP90105263A 1989-03-23 1990-03-20 Farbkathodenstrahlröhre Expired - Lifetime EP0388901B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP69320/89 1989-03-23
JP6932089 1989-03-23
JP1257091A JP2825287B2 (ja) 1989-03-23 1989-10-03 カラー受像管装置
JP257091/89 1989-10-03

Publications (3)

Publication Number Publication Date
EP0388901A2 EP0388901A2 (de) 1990-09-26
EP0388901A3 EP0388901A3 (de) 1991-08-28
EP0388901B1 true EP0388901B1 (de) 1996-03-06

Family

ID=26410519

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90105263A Expired - Lifetime EP0388901B1 (de) 1989-03-23 1990-03-20 Farbkathodenstrahlröhre

Country Status (4)

Country Link
EP (1) EP0388901B1 (de)
JP (1) JP2825287B2 (de)
KR (1) KR930000353B1 (de)
DE (1) DE69025634T2 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100337858B1 (ko) * 1994-10-31 2002-10-25 삼성에스디아이 주식회사 칼라음극선관용전자총
KR100319087B1 (ko) * 1994-12-31 2002-08-13 삼성에스디아이 주식회사 칼라음극선관용전자총
KR100377399B1 (ko) * 1995-11-24 2003-06-19 삼성에스디아이 주식회사 칼라음극선관용전자총
AU2002366421A1 (en) * 2001-12-17 2003-06-30 Koninklijke Philips Electronics N.V. Cathode ray tube and picture display device
KR100786874B1 (ko) * 2006-11-27 2007-12-20 삼성에스디아이 주식회사 음극선관용 전자총 및 음극선관

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0315269A1 (de) * 1987-11-04 1989-05-10 Koninklijke Philips Electronics N.V. Farbbildröhre, Ablenksystem und Elektronenstrahlerzeugungssystem

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2201536B1 (de) * 1972-09-26 1976-08-13 Thomson Csf
NL8203322A (nl) * 1982-08-25 1984-03-16 Philips Nv Kleurenbeeldbuis.
US4528476A (en) * 1983-10-24 1985-07-09 Rca Corporation Cathode-ray tube having electron gun with three focus lenses
NL8600117A (nl) * 1986-01-21 1987-08-17 Philips Nv Kleurenbeeldbuis met verminderde deflectie defocussering.
US4737682A (en) * 1987-07-20 1988-04-12 Rca Corporation Color picture tube having an inline electron gun with an einzel lens

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0315269A1 (de) * 1987-11-04 1989-05-10 Koninklijke Philips Electronics N.V. Farbbildröhre, Ablenksystem und Elektronenstrahlerzeugungssystem

Also Published As

Publication number Publication date
KR930000353B1 (ko) 1993-01-16
KR900015234A (ko) 1990-10-26
JP2825287B2 (ja) 1998-11-18
DE69025634T2 (de) 1996-10-02
DE69025634D1 (de) 1996-04-11
EP0388901A3 (de) 1991-08-28
EP0388901A2 (de) 1990-09-26
JPH0320937A (ja) 1991-01-29

Similar Documents

Publication Publication Date Title
EP0424888B1 (de) Farbbildkathodenstrahlröhre
EP0693768B1 (de) Farbkathodenstrahlröhre
US4935663A (en) Electron gun assembly for color cathode ray tube apparatus
US4764704A (en) Color cathode-ray tube having a three-lens electron gun
US5066887A (en) Color picture tube having an inline electron gun with an astigmatic prefocusing lens
US5262702A (en) Color cathode-ray tube apparatus
US6339293B1 (en) Cathoderay tube
EP0388901B1 (de) Farbkathodenstrahlröhre
US6339284B1 (en) Color cathode ray tube apparatus having auxiliary grid electrodes
EP0361455B1 (de) Vorrichtung für eine Farbkathodenstrahlröhre
US5177399A (en) Color cathode ray tube apparatus
KR20000011965A (ko) 칼라음극선관
US5763993A (en) Focusing electrode structure for a color cathode ray tube
EP0778605B1 (de) Elektronenkanonenvorrichtung für eine Farbkathodenstrahlröhre
US5994826A (en) Color cathode ray tube
US5861710A (en) Color cathode ray tube with reduced moire
JP3672390B2 (ja) カラー陰極線管用電子銃
US5325013A (en) Cathode-ray tube with improved electron gun
EP1204131B1 (de) Farbkathodenstrahlröhre
EP0275191A2 (de) Farbbildröhre mit einer Drei-Linsen-Elektronenkanone
JP3734327B2 (ja) カラーブラウン管装置
EP0348912A2 (de) Farbbildröhre
KR100267978B1 (ko) 칼라 음극선관용 전자총
JPH02135650A (ja) カラー陰極線管
JP2002197990A (ja) 陰極線管装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19900417

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB

17Q First examination report despatched

Effective date: 19940223

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REF Corresponds to:

Ref document number: 69025634

Country of ref document: DE

Date of ref document: 19960411

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: 746

Effective date: 19981008

REG Reference to a national code

Ref country code: FR

Ref legal event code: D6

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20070314

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20070315

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20070308

Year of fee payment: 18

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20080320

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20081125

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20081001

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080320