EP1209718A1 - Farbbildröhre - Google Patents

Farbbildröhre Download PDF

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Publication number
EP1209718A1
EP1209718A1 EP00125213A EP00125213A EP1209718A1 EP 1209718 A1 EP1209718 A1 EP 1209718A1 EP 00125213 A EP00125213 A EP 00125213A EP 00125213 A EP00125213 A EP 00125213A EP 1209718 A1 EP1209718 A1 EP 1209718A1
Authority
EP
European Patent Office
Prior art keywords
electromagnetic
electron beams
quadruple lens
center
color picture
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.)
Withdrawn
Application number
EP00125213A
Other languages
English (en)
French (fr)
Inventor
Toshihiko Tanaka
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to EP00125213A priority Critical patent/EP1209718A1/de
Publication of EP1209718A1 publication Critical patent/EP1209718A1/de
Withdrawn legal-status Critical Current

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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
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/861—Vessels or containers characterised by the form or the structure thereof
    • 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
    • H01J29/701—Systems for correcting deviation or convergence of a plurality of beams by means of magnetic fields at least
    • H01J29/702—Convergence correction arrangements therefor
    • H01J29/705—Dynamic convergence systems

Definitions

  • the present invention relates to an inline type color picture tube.
  • a color picture tube having a flat panel outer surface has been developed.
  • a method which gives a curvature to the panel inner surface while maintaining the flat panel outer surface has an advantage that the method allows a shadow mask to have a curved surface so that the conventional shadow mask manufacturing technique is available.
  • the curvature of the panel inner surface is preferably as small as possible.
  • the shadow mask can be manufactured easier when the curvature thereof is large.
  • the first invention also changes the dimension s at the center of a screen and at the periphery of the screen corresponding to a deflection current using two electromagnetic quadruple lenses.
  • two electromagnetic quadruple lenses are arranged at a side closer to a cathode of an electron gun than a horizontal deflection coil. Due to such a constitution, two electromagnetic quadruple lenses are substantially arranged outside the deflection magnetic field. Accordingly, it is unnecessary to largely change the dimension s in the deflection magnetic field and hence, the control of the convergence and the purity can be performed easily.
  • the first invention it becomes possible to largely change the dimension s which substantially determines the curvature of the shadow mask while maintaining the level of convergence and purity. Accordingly, even when the outer surface is flat, it becomes possible to give a relatively large curvature to a shadow mask and hence, the shadow mask can maintain the practical strength.
  • the first electromagnetic quadruple lens when electron beams scan a central portion of the screen, has a function of moving the side electron beams away from the center electron beam and the second electromagnetic quadruple lens has a function of making the side electron beams parallel to the center electron beam.
  • the first electromagnetic quadruple lens weakens the function of moving the side electron beams away from the center electron beam and the second electromagnetic quadruple lens maintains the function of making the side electron beams parallel to the center electron beam.
  • the dimension s at the periphery of the screen can be substantially made smaller than the dimension s at the center of the screen so that the curvature of the shadow mask can be increased.
  • the second electromagnetic quadruple lens may be arranged in the deflection magnetic field.
  • Fig. 1 is a schematic view of a color picture tube of the present invention.
  • Fig. 2 is an explanatory view showing the arrangement of slots formed in a shadow mask.
  • Fig. 3 is a detailed view of a panel.
  • Fig. 4 is an explanatory view of a prior art where the dimension s is substantially changed.
  • Fig. 5 is an explanatory view of the present invention.
  • Fig. 6 and Fig. 7 are explanatory views showing the first embodiment of the present invention.
  • Fig. 8 is a detailed view of an essential part of the present invention.
  • Fig. 9, Fig. 10 and Fig. 11 are detailed views of an electromagnetic quadruple portion of the present invention.
  • Fig. 12 and Fig. 13 are explanatory views showing the second embodiment of the present invention.
  • Fig. 14 and Fig. 15 are explanatory views showing the third embodiment of the present invention.
  • Fig. 16 is a view showing an example of an electron gun.
  • Fig. 17 is a perspective view showing an example of a main lens portion of the electron gun.
  • Fig. 18 is a view showing an example of a shadow mask used is a display tube.
  • Fig. 1 is a schematic view showing a color cathode ray tube having a flat outer surface.
  • a panel 1 has a flat outer surface and a curved inner surface. The panel inner surface is provided with a curvature to give a curvature to a shadow mask 5 which faces the panel inner surface in an opposed manner.
  • a neck 2 mounts an electron gun 9 arranged in an inline array therein and is contiguously connected with the panel 1 by way of a funnel 3.
  • a crossing point 32 where a reference line 31 and a tube axis cross each other is defined as a deflection center.
  • a deflection angle ⁇ An angle made by a line which connects a point where an electron beam 91 impinges on a phosphor surface 4 and the deflection center 32 and a tube axis is defined as a deflection angle ⁇ .
  • This reference line 32 becomes a basis in designing the color picture tube and is set at a position closer to the panel side than a seal portion defined between the neck 2 and the funnel 3.
  • the maximum deflection angle means a doubled value of an angle made by a line which connects a diagonal axis end portion of an effective screen of the panel inner surface and the deflection center 32 and the tube axis.
  • the maximum deflection angle in this embodiment is set to approximately 110 degrees.
  • a phosphor in a stripe pattern is formed on the phosphor screen 4.
  • the shadow mask 5 is provided with a large number of slot apertures and is supported by means of a support frame 6.
  • the support frame 6 is mounted on the panel 1 by way of springs 8.
  • Fig. 2 shows an example of the slot aperture arrangement of the shadow mask 5.
  • Pm indicates a horizontal pitch of the slots 51.
  • An inner magnetic shield 7 is mounted on the support frame 6.
  • a deflection yoke 10 which deflects electron beams is mounted on a cone portion 33 of the funnel 3.
  • An essential part of the deflection yoke 10 is comprised of a horizontal deflection coil 101, a separator 102, a vertical deflection coil 103 and a core 104.
  • Rod-like magnets 11 which adjust the raster distortion and convergence are mounted above and below the horizontal deflection coil 101.
  • first electromagnetic quadruple lens 14 first electromagnetic quadruple coils
  • second electromagnetic quadruple lens 15 second electromagnetic quadruple coils
  • the outer surface of the panel 1 is made flat or has an extremely large radius of curvature.
  • An example of the panel curved surface obtained by applying the present invention to a 36V type CPT is shown in following tables.
  • the radii of curvature are different depending on the locations.
  • the equivalent radius of curvature which is based on the drop amount in the diagonal direction shown in Fig. 3 can be employed.
  • the inner surface has the larger curvature than the outer surface.
  • the curved surface of the shadow mask becomes a curved surface substantially equal to the inner surface of the panel.
  • L is the distance from the deflection center to the shadow mask
  • Pm is the horizontal pitch of the mask
  • s is the effective beam distance on the deflection center.
  • Fig. 4 shows a conventional example which adopts this principle.
  • numeral 911 indicates an electron beam which scans the center of the screen
  • numeral 912 indicates an electron beam which scans the periphery of the screen.
  • Respective parameters q, L, s have their values expressed by q0, L0, s0 at the center of the screen and by q1, L1, s1 at the periphery of the screen.
  • the dimension s1 in the periphery of the screen is made smaller than the value s0 at the center of the screen so that the dimension q in the periphery of the screen is increased whereby the curvature is given to the shadow mask.
  • the problem that this method has is that, in the deflection region of electron beams including the deflection center, the actual dimension s is largely changed so that the control of the convergence and the purity on the screen becomes difficult. That is, both of the convergence and the purity are largely changed depending on the dimension s in the vicinity of the deflection center.
  • Fig. 5 shows the present invention. Respective symbols are identical with symbols in Fig. 4.
  • the first electromagnetic quadruple lens 14 and the second electromagnetic quadruple lens 15 are arranged at a side closer to a cathode of the electron gun than the horizontal deflection coil of the deflection yoke 10. Due to such a constitution, when the electron beams advance into the deflection region of electron beams including the deflection center, three electron beams establish an approximately parallel relationship relative to the tube axis of the cathode ray tube. Since three electron beams can be made substantially parallel to the tube axis in a sensitive region called the deflection region, the control of the convergence and the purity can be performed easily.
  • FIG. 7 are schematic views showing the surrounding of the deflection yoke 10 of the present invention.
  • Fig. 6 shows a case in which electron beams are not deflected. No electric current is supplied to a pair of electromagnetic quadruple coils 14, 15 so that the electron beams advance linearly.
  • Fig. 7 shows a case in which electron beams are deflected. An electric current proportional to the deflection current is supplied to the first electromagnetic quadruple coils 14 and the second electromagnetic quadruple coils 15.
  • Fig. 8 is a detailed view of a portion where the electromagnetic quadruple coils 14, 15 are mounted. In this embodiment, the electromagnetic quadruple coils 14, 15 are mounted in the vicinity of a shield cup of the electron gun 9.
  • the electromagnetic quadruple coils 14,15 may preferably be mounted between the rear end of the horizontal deflection coil 101 and the main lens of the electron gun 9. Since the electromagnetic quadruple lenses 14, 15 change the dimension s, by arranging the electromagnetic quadruple lenses 14,15 at a position which three electron beams reach after passing the main lens of the electron gun 9, the influence given to focusing by the electromagnetic quadruple lenses 14, 15 can be reduced.
  • Fig. 9 is a cross-sectional view of a shield cup 50 of this embodiment.
  • Numeral 51, 52 indicate pole pieces for forming the electromagnetic quadruple lens.
  • Fig. 10 and Fig. 11 are operational views. In Fig. 10, in the vicinity of the cross section A-A of Fig.
  • the coils forming the first quadruple lens 14 are mounted and they are operated so as to decrease the dimension s of the electron beams.
  • the coils forming the second quadruple lens 15 are mounted and they are operated so as to make both side electron beams approximately parallel to the tube axis of the cathode ray tube.
  • Pole pieces 51, 52 are not always necessary. In this case, it is not always necessary to position the coils forming the quadruple lens 14, 15 in the vicinity of the shield cup 50.
  • the coils of the electromagnetic quadruple lens 14, 15 may be integrally formed with the magnet assembly 12. Further, the coils forming the first electromagnetic quadruple lens 14 may be integrated with the magnet assembly 12 while the coils forming the second electromagnetic quadruple lens 15 may be integrated with the deflection yoke 10.
  • Fig. 12 and Fig. 13 show the second embodiment of the present invention. Contrary to the first embodiment, this embodiment increases the dimension s by supplying an electric current to the coils of the electromagnetic quadruple lens in the vicinity of the center of the screen. In this case, an electric current which generates a magnetic field for increasing the dimension s is supplied to the coils of the first quadruple lens 14 and an electric current which generates a magnetic field for making electron beams parallel to the tube axis of the cathode ray tube is supplied to the coils of the second quadruple lens 15. Then, as shown in Fig.
  • the second electromagnetic quadruple lens 15 may be arranged in the deflection magnetic field.
  • Fig. 14 and Fig. 15 show the third embodiment of the present invention.
  • an electric current which effectively increases the dimension s is supplied to the coils forming the electromagnetic quadruple lens 14, 15 and, at the periphery of the screen, for example, at the diagonal end of the screen, an electric current which effectively decreases the dimension s is supplied to the coils forming the electromagnetic quadruple lens 14, 15.
  • An advantage of this embodiment lies in that at the center of the screen and at the periphery of the screen, without extremely changing the magnitude of the dimension s, it becomes possible to give a large curvature to the shadow mask 5.
  • the second electromagnetic quadruple lens 15 may be arranged in the deflection magnetic field.
  • Fig. 16 shows an example of an electron gun employed in the present invention.
  • Fig. 16 is a longitudinal cross-sectional view of the electron gun.
  • numeral 40 indicates cathodes and three cathodes are arranged in a direction perpendicular to this paper surface at an interval of 5.5 mm.
  • a center electron beam and two side electron beams are irradiated from three cathodes 40.
  • Numeral 41 indicates control electrodes G1 and numeral 42 indicates an acceleration electrode G2.
  • a front-stage lens is constituted by electrodes 43, 44 and 45.
  • a static focusing voltage Vfs is applied to the electrodes 43 and 45 while a voltage identical to a voltage applied to the acceleration electrode 42 is applied to the electrode 44.
  • a so-called UPF lens is constituted by these three electrodes.
  • all electrodes 46, 47, 48 respectively constitute focusing electrodes, they are divided to form a lens having dynamic characteristics.
  • a dynamic focusing voltage which elevates a voltage corresponding to a deflection angle is applied to the electrode 46 and the electrode 48, while a static focusing voltage is applied to the electrode 47.
  • An aperture formed in a portion 451 of the electrode 45 is laterally elongated while an aperture formed in a portion 461 of the electrode 46 is longitudinally elongated. Due to such a constitution, an electrostatic quadruple lens is formed together with an application of a dynamic voltage.
  • Numeral 462 indicates a horizontal-plate-like electrode and numeral 472 indicates a vertical-plate-like electrode.
  • Another electrostatic quadruple lens is formed of these two electrodes. Longitudinally elongated apertures are respectively formed in portions 471, 481 of the electrodes 47, 48. Due to these elongated apertures, the lens intensity is changed along with the application of the dynamic voltage and a lens which elongates the electron beams longitudinally is formed. An anode voltage which is a maximum voltage is applied to an anode electrode 49 and a main lens is formed between the electrode 48 and the electrode 49. The lens intensity of this main lens is decreased along with the elevation of the dynamic voltage.
  • Numeral 482 indicates a plate-like electrode having a longitudinally elongated aperture which is disposed in the inside of the focusing electrode 48 and numeral 491 indicates a plate-like electrode having a longitudinally elongated aperture which is disposed in the inside of the anode electrode 49.
  • Fig. 8 is a detailed view of the main lens portion.
  • the inner electrodes 482, 491 respectively have three longitudinally elongated apertures, apertures may be formed only in the central portions of the inner electrodes 482, 492.
  • the present invention is also applicable to a cathode ray tube which has a phosphor screen of dot type, a shadow mask having circular apertures and an electron gun in an inline array.
  • a cathode ray tube is used as a high definition display tube whose dot pitch on a phosphor screen is small.
  • the apertures formed in the shadow mask are arranged as shown in Fig. 18.
  • the horizontal pitch Ph on the shadow mask is set to not more than 0.41 mm at the center of the screen.
  • the shadow mask aperture has a diameter of approximately ⁇ 0.11 mm.
  • the plate thickness of the shadow mask which has a large influence on the shadow mask strength may be of the thin thickness of approximately 0.14 mm in view of etching. Accordingly, unless the sufficient curvature is given to the shadow mask, it becomes difficult to ensure the shadow mask strength.
  • the present invention is particularly advantageous in such a high definition display tube.

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  • Video Image Reproduction Devices For Color Tv Systems (AREA)
EP00125213A 2000-11-22 2000-11-22 Farbbildröhre Withdrawn EP1209718A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP00125213A EP1209718A1 (de) 2000-11-22 2000-11-22 Farbbildröhre

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Application Number Priority Date Filing Date Title
EP00125213A EP1209718A1 (de) 2000-11-22 2000-11-22 Farbbildröhre

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EP1209718A1 true EP1209718A1 (de) 2002-05-29

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EP00125213A Withdrawn EP1209718A1 (de) 2000-11-22 2000-11-22 Farbbildröhre

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5536995A (en) * 1993-11-16 1996-07-16 Asahi Glass Company Ltd. Glass bulb for a cathode ray and a method of producing the same
WO1999034392A1 (en) * 1997-12-29 1999-07-08 Koninklijke Philips Electronics N.V. Color display device with a deflection-dependent distance between outer beams
EP0975003A1 (de) * 1998-07-16 2000-01-26 Matsushita Electronics (Europe) GmbH Farbfernsehgerät oder Farbmonitor mit flachem Bildschirm
WO2000033349A1 (en) * 1998-12-01 2000-06-08 Koninklijke Philips Electronics N.V. Colour display device with a deflection-dependent distance between outer beams
EP1117123A1 (de) * 1999-12-24 2001-07-18 Hitachi, Ltd. Inline-Farbbildröhre

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5536995A (en) * 1993-11-16 1996-07-16 Asahi Glass Company Ltd. Glass bulb for a cathode ray and a method of producing the same
WO1999034392A1 (en) * 1997-12-29 1999-07-08 Koninklijke Philips Electronics N.V. Color display device with a deflection-dependent distance between outer beams
EP0975003A1 (de) * 1998-07-16 2000-01-26 Matsushita Electronics (Europe) GmbH Farbfernsehgerät oder Farbmonitor mit flachem Bildschirm
WO2000033349A1 (en) * 1998-12-01 2000-06-08 Koninklijke Philips Electronics N.V. Colour display device with a deflection-dependent distance between outer beams
EP1117123A1 (de) * 1999-12-24 2001-07-18 Hitachi, Ltd. Inline-Farbbildröhre

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
A.A.S. SLUYTERMAN, IDW '98, 7 December 1998 (1998-12-07), pages 413-416, XP002165512 *

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