JP2006139959A - Color picture tube and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance withstand voltage characteristics of a color picture tube while suppressing deterioration of resolution. <P>SOLUTION: This color picture tube is structured so as to include a housing, a phosphor screen, an internal conductive film, and an electron gun equipped with a beam generating part having three aligned negative electrodes and a plurality of electrodes, a main lens part having a plurality of electrodes and a positive electrode, and insulated supports 57A, 57B to support the main lens part and the beam generating part. It is also structured so as to include an metal member 8A which covers a part of the insulated supports 57A, 57B, which is connected to at least one electrode 54 among a plurality of the electrodes in the beam generating part and a plurality of the electrodes in the main lens part so as to cover a part of the insulated supports 57A, 57B, and which has a loop part 18 having a loop shape, and conductive films 9A, 9B formed in a region facing the metal member 8A on the inner wall of a neck part 2A and segregated from the internal conductive film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color picture tube, and more particularly to a high-resolution color picture tube. More particularly, the present invention relates to a color picture tube having an excellent withstand voltage characteristic and an elaborate electron gun.

  A conventional color picture tube has a panel, a funnel-shaped funnel having a neck portion, a glass envelope having a sealing portion, a phosphor screen formed on the inner wall of the panel, and a sealed inner space of the neck portion. Including a stopped electron gun. A panel is joined to the opening end on the large-diameter side of the funnel, and a sealing portion is joined to the opening end on the small-diameter side (neck portion side) of the funnel. The neck portion is the most detailed part of the funnel, and is generally a cylinder having a diameter of about 20 to 40 mm. The sealing part is a disk having a diameter substantially the same as the diameter of the neck part. The sealing portion is formed with a plurality of metal stem pins that penetrate the sealing portion. This stem pin is provided for electrical connection between the outside and the inside of the envelope. Note that the sealing portion and the stem pin are collectively referred to as a stem portion. The phosphor screen includes a red phosphor, a green phosphor, and a blue phosphor. The electron gun is supported in the internal space of the neck portion by a plurality of metal stem pins.

  An electron gun used for a conventional color picture tube is mainly an in-line type electron gun including three electron guns arranged in a line. In an in-line type electron gun, an electron beam for emitting a green phosphor is usually emitted from an electron gun (center gun) located in the center among three electron guns arranged in a row, and emits a red phosphor. The electron beam for causing the light emission and the electron beam for causing the blue phosphor to emit light are respectively emitted from an electron gun (side gun) located on the side of the center gun.

  An in-line type electron gun generally includes a beam generation unit (triode unit) including three cathodes corresponding to three electron beams, a first electrode (control electrode) and a second electrode (acceleration electrode), a focusing electrode, And a main lens unit that has a final acceleration electrode (anode) and focuses each of the three electron beams from the beam generation unit on the phosphor screen. The focusing electrode is composed of a plurality of electrodes spaced apart from each other. The three electron beams emitted from the three cathodes are guided to the main lens portion through the beam passage holes of the first electrode and the second electrode. Each of the three types of electron beams passes through the beam passage holes of the respective electrodes constituting the main lens portion, and is finally focused on the phosphor screen.

  In the in-line type electron gun, an implanted portion (strap) is formed on each electrode constituting the beam generating portion and the main lens portion, and the implanted portion is embedded in an insulating support made of glass or the like.

  The final acceleration electrode and the focusing electrode are generally arranged so that their beam passage holes face each other with an interval of about 1 mm. By supplying a predetermined voltage to the final accelerating electrode and the focusing electrode, a main lens is formed in a region opposite to these electrodes. Generally, the length of the focusing electrode among the electrodes constituting the electron gun is the longest in the tube axis direction of the color picture tube.

  A direct current voltage of several hundreds of volts is applied to each cathode of the beam generating unit, 0 volts (electrically grounded) to the first electrode, and several hundred volts to the second electrode through a stem pin. A DC voltage (anode high voltage) of several thousand volts is supplied to the final acceleration electrode through an internal conductive film, a shield cup, and a contact element formed on the inner wall of the funnel. In addition, a voltage of about 20% to 40% of the final acceleration electrode is supplied to the plurality of electrodes constituting the main lens portion from the outside through the stem pin.

  In a conventional color picture tube, the inner conductive film for supplying anode high voltage to the final acceleration electrode is usually formed on the inner wall of the neck portion to the extent that it overlaps with part of the final acceleration electrode or part of the contact element. ing. The inner wall of the neck portion from the end on the neck portion side in the region where the internal conductive film is formed (hereinafter referred to as the internal conductive film end) to the sealing portion is in a state where the glass constituting the neck portion is exposed. It has become. Therefore, the portion of the inner wall of the neck portion where the internal conductive film is not formed is charged up to a predetermined potential according to the potential of the internal conductive film (anode high voltage). The potential of the inner wall of the neck portion (hereinafter also referred to as neck potential) shows a distribution that decreases as the distance from the end of the internal conductive film increases. The neck potential at the portion facing the electrode other than the final acceleration electrode is usually higher than the potential applied to the electrode. In this case, electrons are easily emitted from the electrode due to the potential difference between the neck potential and the electrode potential. That is, a leak current is likely to occur between the electrode other than the final acceleration electrode and the neck portion. This means that the withstand voltage characteristic is deteriorated.

  As a countermeasure, a technique is commonly used in which a metal vapor deposition film separated from the internal conductive film is formed on the inner wall of the neck portion to reduce the neck potential in the region where the metal vapor deposition film is formed (for example, Patent Documents 1 to 4). reference). If a metal vapor deposition film is formed, the neck potential in the region where the metal vapor deposition film is formed can be stabilized by electrostatic induction at a potential close to the potential of the electrode facing the metal vapor deposition film. Thereby, the withstand voltage characteristic of the color picture tube is improved.

  Here, a conventional method for forming a metal vapor deposition film on the inner wall of the neck portion will be described. FIG. 9A is a schematic front view showing a structural example in the vicinity of a metal member in order to explain a process of forming a metal vapor deposition film in the manufacture of a conventional typical color picture tube. B) is a schematic top view thereof. As shown in FIG. 9A or 9B, in the internal space of the neck portion 2A, a quadrilateral metal member 108A that is a material for forming the metal vapor deposition film 109A, for example, about 0.2 mm thick A thin stainless steel material (metal ribbon) is connected to the electrode 54 constituting the electron gun so as to cover a part of the insulating support 57A. Similarly, a quadrilateral metal member 108B, which is a material for forming the metal vapor-deposited film 109B, is connected to the electrode 54 so as to cover a part of the insulating support 57B.

With the external coil 197 disposed so that the central axis of the neck portion 2A (the tube axis of the color picture tube) and the central axis of the external coil 197 coincide with each other, a high-frequency current is supplied to the external coil 197 to A high frequency magnetic field is generated in the internal space. By induction heating with a high-frequency magnetic field, the materials constituting the two quadrilateral metal members 108A and 108B evaporate, and two metal deposition films 109A and 109B are formed on the inner wall of the neck portion 2A. In this case, an eddy current (Ip: broken line arrow in FIG. 9A) is also generated in the electrode 54 and the like, and not only the metal members 108A and 108B but also the electrode 54 and the like are heated.
JP-A-9-161690 JP 2001-35421 A JP 2001-176421 A JP 2002-203493 A

  In the case of a conventional color picture tube provided with a metal vapor deposition film for improving the withstand voltage characteristics, when the metal vapor deposition film is formed, the electrodes constituting the electron gun are heated to cause expansion of the electrodes. Stress was generated in a direction to push away the pair of insulating supports. Due to this stress, the position of the insulating support changed or the electrode itself was deformed. In other words, the axes of the electron lenses that should normally be arranged on the same axis are shifted. This phenomenon is generally referred to as an axis shift of the electron gun. As a result, in the conventional color picture tube having the metal vapor deposition film, the focus characteristic is deteriorated due to the axial deviation of the electron gun, and the resolution is deteriorated due to the deterioration of the focus characteristic.

  Therefore, in the present invention, the withstand voltage characteristic of the color picture tube is improved, and the deterioration of the resolution is suppressed. This provides a color picture tube excellent in both withstand voltage characteristics and resolution.

  In order to solve the above problems, a color picture tube according to the present invention includes a panel, a funnel having a neck portion, an envelope having a sealing portion, a phosphor screen formed on the inner wall of the panel, and a funnel. An inner conductive film formed on the inner wall of the substrate, three cathodes arranged in a row and a plurality of electrodes, a beam generating section for generating a three electron beam, a plurality of electrodes and an anode, and three electrons A color picture tube including a main lens portion for focusing each beam on a phosphor screen, and an electron gun provided in an internal space of the neck portion, including an insulating support for supporting the beam generation portion and the main lens portion. A metal member connected to at least one of the plurality of electrodes of the beam generating portion and the plurality of electrodes of the main lens portion and having a loop-shaped loop portion so as to cover a part of the insulating support. , Neck part It is formed in a region opposed to the metallic member in the inner wall, and further comprising a conductive film spaced apart from the inner conductive film.

  In order to solve the above problems, a color picture tube manufacturing method according to the present invention includes (1) a step of forming a phosphor screen on the inner wall of a face panel, and (2) an inner wall of a funnel having a neck portion. A step of forming an internal conductive film on the substrate, (3) a step of bonding the face panel and the funnel after forming the phosphor screen and the internal conductive film, and (4) three cathodes and a plurality of electrodes. A beam generating unit that generates three electron beams, a plurality of electrodes and an anode, a main lens unit that controls focusing of each of the three electron beams, and an insulating support that supports the beam generating unit and the main lens unit A step of manufacturing an electron gun provided with a body, a step of manufacturing a metal member, and (5) a plurality of electrodes of a beam generation unit and a plurality of electrodes of a main lens unit so as to cover a part of an insulating support. At least one of them (6) After fixing the metal member to the electron gun, the electron gun is placed in the inner space of the neck portion, and the sealing portion and the funnel are joined to form the neck of the electron gun. (7) After sealing the electron gun, high-frequency heating using an external coil is used to deposit a material constituting the metal member on the inner wall of the neck portion to form a conductive film. Manufacturing a color picture tube, wherein the metal member has a loop portion having a loop shape, and in the step of forming the conductive film, an eddy current is generated along the loop portion. And

  With the color picture tube according to the present invention, the withstand voltage characteristic is improved by forming a conductive film spaced from the internal conductive film on the inner wall of the neck portion. In addition, in the case of the color picture tube according to the present invention, the metal member as the material for forming the conductive film has the loop portion, so that the loop portion can be selectively and efficiently heated when forming the conductive film, It is possible to suppress the occurrence of misalignment of the electron gun. Therefore, the withstand voltage characteristics are improved and resolution degradation due to the axial deviation of the electron gun is suppressed.

  With the method of manufacturing a color picture tube according to the present invention, the loop portion of the metal member can be selectively and efficiently heated when forming the conductive film. As a result, the conductive film can be formed while suppressing the occurrence of axial misalignment of the electron gun. Therefore, it is possible to manufacture a color picture tube excellent in both withstand voltage characteristics and resolution.

  As described above, the color picture tube according to the present invention includes a panel, an envelope having a funnel having a neck portion and a sealing portion, a phosphor screen formed on the inner surface of the panel, and an internal space of the neck portion. An electron gun provided on the inner wall of the funnel, an inner conductive film formed on the inner wall of the funnel, a conductive film formed on the inner wall of the neck portion and separated from the inner conductive film, and a metal member fixed to the electron gun. The color picture tube generally further includes a deflector for deflecting an electron beam emitted from the electron gun by an electric action or a magnetic action. Usually, the deflector in the color picture tube is provided on the outer edge of the funnel, and deflects the electron beam by magnetic action. The color picture tube of the present invention may have the same configuration as any known color picture tube other than the conductive film and the metal member.

  In the color picture tube according to the present invention, at least one metal member is formed. The metal member is connected to at least one of the plurality of electrodes of the beam generating unit and the plurality of electrodes of the main lens unit so as to cover a part of the insulating support. The metal member may be connected to one electrode, or may be connected to two or more electrodes. It is preferable that the metal member is disposed so as to straddle part of the insulating support, and both ends of the metal member are connected to the electrodes. This is because the metal member can be firmly fixed on the insulating support.

  When a metal member is connected to one electrode, the metal member and the electrode may be connected to each other, or the metal member and the electrode may be connected to be electrically insulated. From the viewpoint of improving the withstand voltage characteristic, the former is preferable. This is because the potential of the conductive film induced by electrostatic induction is closer to the potential of the electrode in the former than in the latter.

  When a metal member is connected to two electrodes to which the same DC voltage is supplied, the metal member and each electrode may be connected so that the metal member and each electrode are electrically insulated. You may connect as follows. On the other hand, when a metal member is connected to two electrodes to which different DC voltages are supplied, the two electrodes must be connected so as to be electrically insulated. The same applies when a metal member is connected to three or more electrodes.

  The conductive film is a vapor deposition film formed by vapor deposition using a metal member as a material. By forming a conductive film on the inner wall of the neck portion, the withstand voltage characteristic can be improved. The color picture tube of the present invention may include a plurality of conductive films that are spaced apart from the internal conductive film and spaced apart from each other.

  In the color picture tube according to the present invention, the loop portion of the metal member is preferably arranged on a plane substantially parallel to a plane including the tube axis and the arrangement direction of the three cathodes. This is because if the entire loop portion is kept flat, generation of eddy currents in the loop portion can be promoted when forming the conductive film, and the loop portion can be heated more efficiently. Further, the distance between each electrode constituting the electron gun and the neck portion is larger in the direction perpendicular to the arrangement direction of the three cathodes and the tube axis than in the arrangement direction of the three cathodes, and the interval between the electrodes and the loop portion. This is because the loop portion can be further selectively heated when forming the conductive film. The substantially parallel plane implies a case where the plane is not strictly parallel.

  In the color picture tube according to the present invention, the loop portion of the metal member is preferably disposed on the insulating support of the electron gun. This is because the surface of the insulating support opposite to the electrode is generally flat, so that the entire loop portion can be easily kept flat. Moreover, since the whole loop part is reliably kept away from the electrode to which the metal member is connected, the loop part can be further selectively heated when the conductive film is formed.

  Hereinafter, specific examples of the color picture tube according to the present invention will be described with reference to the drawings. For convenience of explanation, the arrangement direction of the three cathodes orthogonal to the tube axis of the color picture tube is defined as the horizontal direction, and the direction orthogonal to the horizontal direction and the tube axis direction is defined as the vertical direction.

  FIG. 1 is a schematic partial plan view showing a structural example of a color picture tube. As shown in FIG. 1, the color picture tube includes a panel 1, an envelope provided with a funnel 2 having a neck portion 2A and a sealing portion 3, a phosphor screen 4, an electron gun 5, a deflection yoke. (Deflector) 6, internal conductive film 7, two metal members 8, two metal deposition films (conductive film) 9, and a plurality of stem pins 10 penetrating sealing part 3. Except for the two metal members 8 and the two metal vapor deposition films 9, the same structure as any known color picture tube may be used.

  The electron gun 5 includes a beam generator 11 having three cathodes 50, a first electrode 51 and a second electrode 52, a third electrode 53, a fourth electrode 54, a fifth electrode 55 and a sixth electrode (anode, final acceleration). This is an electron gun having a QPF structure including a main lens portion 12 having electrodes 56, two insulating supports 57, three cathode heaters 58, a shield cup 61, and a plurality of contact elements 62. .

  FIG. 2A is a schematic side view partially showing a structural example in the vicinity of the neck portion in the color picture tube, and FIG. 2B is a schematic top view thereof. 2A shows the case where the neck part and the member formed on the neck part are partially cut and viewed from the horizontal direction, and FIG. 2B shows the member formed on the neck part and the neck part. This represents a case in which is partially cut and viewed from the vertical direction.

  As shown in FIG. 2 (A) or (B), each of the first electrode 51 to the sixth electrode 56 is implanted in two substantially parallel insulating supports 57 opposed in the vertical direction, The relative position of each electrode is fixed. The shield cup 61 is fixed to the sixth electrode 56 by welding. Each of the plurality of contact elements 62 is fixed to the shield cup 61 by welding and is in contact with the internal conductive film 7.

  Each of the first electrode 51 to the sixth electrode 56 is formed with an aperture through which three electron beams emitted from three cathodes 50R, 50G (not shown) and 50B pass. When a predetermined voltage is supplied to each electrode, an electron lens is formed between the electrodes. The electron lens formed between the fifth electrode 55 and the sixth electrode 56 has a larger potential difference between the fifth electrode 55 and the sixth electrode 56 than between the other electrodes, and each of the three electron beams. Is mainly called a main lens because it is a main lens for focusing the light on the phosphor screen 4 (see FIG. 1).

  The sixth electrode 56 is connected to an inner conductive film 7 and a contact element 62 from an anode terminal (not shown) that conducts electricity inside and outside the envelope formed near the end of the funnel 2 (see FIG. 1) on the panel side. A voltage (anode high voltage) is supplied through the shield cup 61. A voltage is supplied to the three cathodes 50R, 50G, and 50B and the first electrode 51 to the fifth electrode 55 via a plurality of stem pins 10 that penetrate the sealing portion 3. In addition, a current is supplied to each of the three heaters 58R, 58G (not shown), 58B via the plurality of stem pins 10.

  The metal member 8A is connected to the fourth electrode 54 so as to cover a part of the insulating support 57A and the metal member 8B so as to cover a part of the insulating support 57B. The metal vapor deposition film 9A is a film formed by vapor deposition using the metal member 8A as a material, and has a shape corresponding to the metal member 8A. The shape corresponding to the metal member 8A does not mean the same shape as the metal member 8A. Similarly to the metal vapor deposition film 9A, the metal vapor deposition film 9B is a film formed by vapor deposition using the metal member 8B as a material, and has a shape corresponding to the metal member 8B.

  Here, the two metal members 8A and 8B and the two metal deposition films 9A and 9B will be described in more detail. FIG. 3A is a schematic front view showing a structural example in the vicinity of the fourth electrode of the electron gun in the color picture tube, and FIG. 3B is a schematic top view thereof. 3A shows the case where the neck portion and the member formed on the neck portion are partially cut and viewed from the tube axis direction, and FIG. 3B is formed on the neck portion and the neck portion. The case where the member is partially cut and viewed from the vertical direction is shown.

  As shown in FIG. 3A or 3B, the metal member 8A formed so as to cover a part of the insulating support 57A has a circular loop portion 18 and both sides of the circular loop portion 18. Two linear connection portions 28 and 38 are formed. The circular loop portion 18 is disposed on the insulating support 57A. The end portion of the connection portion 28 opposite to the circular loop portion 18 (end portion of the metal member) and the end portion of the connection portion 38 opposite to the circular loop portion 18 (end portion of the metal member) are the fourth electrode. 54. The metal member 8B is the same as that of the metal member 8A.

  The metal vapor deposition film 9A and the metal vapor deposition film 9B are respectively formed in regions facing the metal member 8A and the metal member 8B on the inner wall of the neck portion 2A. When the color picture tube is operated, the two metal vapor-deposited films 9A and 9B are charged up to a potential close to the fourth electrode 54 by electrostatic induction, and the neck potential is compared with the case where the two metal vapor-deposited films 9A and 9B are not formed. Stable at low potential. As a result, leakage current between the neck portion 2A and the fourth electrode 54 can be prevented, and the withstand voltage characteristics are improved. Moreover, if the metal member 8A, the metal member 8B, and the fourth electrode 54 are electrically connected, the withstand voltage characteristic is further improved.

  Here, an example of a method for manufacturing a color picture tube will be described. In the manufacture of the color picture tube, any known technique may be used except for using the two metal members 8A and 8B having the circular loop portion 18 and heating the two metal members 8A and 8B. . In the following, FIGS. 1 to 3 will be referred to as appropriate for convenience.

  As shown in FIG. 1, the panel 1, the funnel 2 having the neck portion 2A, the stem portion having the sealing portion 3 and the stem pin 10 penetrating the sealing portion 3, and the electron gun 5 are prepared in advance. To do.

  In addition, two metal members 8A and 8B each having a circular loop portion 18 and two connection portions 28 and 38 as shown in FIG. The two metal members 8A and 8B are preferably manufactured by pressing or etching. In this case, the metal member 8A and the metal member 8B can be easily and accurately manufactured. Here, these manufacturing methods will be described in detail. In addition, since the same production method can be applied to the production of the two metal members 8A and 8B, a case where the metal member 8A is produced will be described below.

  4A to 4C are explanatory diagrams for explaining an example of a method for producing the metal member 8A by press working. 4A to 4C, the upper diagram is a schematic plan view, and the lower diagram is a schematic diagram showing the AA ′ section, the BB ′ section, and the CC ′ section in the upper diagram, respectively. FIG. As shown in FIG. 4A, a metal base material 93 is placed on a press machine provided with a die 91 and a die 92, and the die 92 is lowered toward the die 91 side. Next, as shown in FIG. 4B, the metal base material 93 is punched with the metal mold 91 and the metal mold 92, and separated into the metal member 8A and the unnecessary metal base material 93 '. Next, as shown in FIG. 4C, the mold 92 is raised and the metal member 8A is taken out. Thereby, the metal member 8A is completed.

  FIGS. 5A and 5B are explanatory views for explaining an example of a method for producing the metal member 8A by etching. As shown in FIG. 5 (A), a metal base 93 is arranged on a base (not shown), and a covering portion that covers the metal base 93A corresponding to a region where the metal member 8A is to be formed on the metal base 93 is covered. After providing (not shown), the metal base material 93 is brought into contact with the etching solution 96 capable of melting the metal base material 93, and the region not covered with the covering portion (the hatch in FIG. The metal base material 93B in the applied region) is melted, except that the etching solution 96 does not penetrate into the interface between the base material and the metal base material 93A and the interface between the covering portion and the metal base material 93A. 5 (B), the covering portion is removed and the metal member 8A is peeled from the base material, thereby completing the metal member 8A.

  As shown in FIG. 1, a phosphor screen 4 is formed on the inner wall of the panel 1. An internal conductive film 7 is formed on the inner wall of the funnel 2. The panel 1 on which the phosphor screen 4 is formed and the funnel 2 on which the internal conductive film 7 is formed are joined.

  As shown in FIG. 3A or 3B, the metal member 8A and the metal member 8B are connected to the fourth electrode 54 so as to cover a part of the insulating support 57A and the insulating support 57B, respectively. To do. For example, the end of each of the two connecting portions 28 and 38 opposite to the circular loop portion 18 is welded to the fourth electrode 54 so that the circular loop portion 18 is disposed on the insulating support 57A. The metal member 8A is fixed. If connected by welding, electrical conduction between the two metal members 8A and 8B and the fourth electrode 54 can be ensured.

  As shown in FIG. 1, the electron gun 5 and the stem portion having the sealing portion 3 and the plurality of stem pins 10 are joined. The joining of the electron gun 5 and the stem portion may be performed before the two metal members 8A and 8B are connected to the fourth electrode 54, or may be performed thereafter.

  As shown in FIGS. 2A and 2B, an electron gun is disposed in the internal space of the neck portion 2A, and the sealing portion 3 and the neck portion 2A are joined to seal the electron gun. In sealing the electron gun, the internal space of the envelope is also decompressed.

  After the electron gun is sealed, as shown in FIGS. 3A and 3B, the metal member 8A is heated at a high frequency using an external coil (not shown), and the material constituting the metal member 8A is changed. A metal vapor deposition film 9A is formed by vapor deposition on the inner wall of the neck portion 2A. At this time, an eddy current along the loop portion 18 is generated by electromagnetic induction by a high-frequency magnetic field generated by an external coil. The metal member 8B is also formed in the same manner as the metal member 8A. The two metal members 8A and 8B may be sequentially heated individually, or may be simultaneously heated using two external coils.

  Here, a method of high-frequency heating the two metal members 8A and 8B will be described in detail. FIG. 6A is a schematic side view showing the vicinity of the fourth electrode in order to explain the step of forming the conductive film, and FIG. 6B is a schematic top view thereof. FIG. 6A shows a case where the neck portion and the member formed on the neck portion are partially cut and viewed from the horizontal direction, and FIG. 6B shows the neck portion and the member formed on the neck portion. It shows the case of cutting from the vertical direction and viewing from the vertical direction.

  As shown in FIG. 6A or 6B, an external coil 97 is disposed on the outer edge of the neck portion 2A above the metal member 8A (rightward in FIG. 6A). After the external coil 97 is disposed, a high frequency voltage is supplied to the external coil 97. A high-frequency magnetic field (a dotted arrow in FIG. 6A represents a magnetic field line of the high-frequency magnetic field at a certain moment) is generated around the external coil 97, and is caused by the action of the high-frequency magnetic field penetrating the inside of the circular loop portion 18. An eddy current (Is: a broken line arrow in FIG. 6B represents an eddy current) is generated in the circular loop portion 18. The metal member 8A is heated by the Joule heat of the eddy current (Is), and the material constituting the metal member 8A is deposited on a region facing the metal member 8A on the inner wall of the neck portion 2A. Thereby, the metal vapor deposition film 9A is formed on the inner wall of the neck portion 2A. The metal member 8B is also formed in the same manner as the metal member 8A.

  In the prior art, as shown in FIGS. 9A and 9B, the central axis of the external coil 197 substantially coincides with the tube axis. However, in the present invention, FIGS. Note that the central axis of the external coil 97 does not coincide with the tube axis as shown in B). The external coil 97 is preferably disposed so that the central axis of the circular loop portion 18 penetrates the internal space of the external coil 97. This is because an eddy current along the circular loop portion 18 can surely be generated. Further, the external coil 97 is preferably arranged so that the central axis of the circular loop portion 18 is substantially parallel to the central axis of the external coil 97. This is because the generation of eddy currents in the circular loop portion 18 can be promoted as compared with the case where they are not parallel. More preferably, the external coil 97 is arranged such that the central axis of the circular loop portion 18 and the central axis of the external coil 97 substantially coincide. In this case, the generation of eddy current in the circular loop portion 18 can be most promoted.

  The magnetic field lines of the high-frequency magnetic field formed at each instant radiate radially from the central axis of the external coil 97 as they move away from the external coil 97, as in the case of the magnetic field lines shown in FIG. The change in the magnetic flux density in the third electrode 53, the fourth electrode 54, the fifth electrode 55, etc. existing at a position farther from the external coil 97 than the loop part 18 is smaller than the change in the magnetic flux density in the circular loop part 18. Become. Therefore, generation | occurrence | production of the eddy current in the 3rd electrode 53, the 4th electrode 54, the 5th electrode 55 grade | etc., Can be suppressed favorably, and the temperature rise of those electrodes can be suppressed favorably. Thereby, the axial shift of the electron gun due to the thermal expansion of the third electrode 53, the fourth electrode 54, the fifth electrode 55, and the like can be prevented.

  When the high frequency output of the external coil 97 is the same (when a high frequency voltage having the same frequency and amplitude is supplied to the same coil), the amount of eddy current generated in the metal member 8A having the circular loop portion 18 is as follows. , 38 as compared with the case of the conventional quadrilateral metal member having the same width. Since the metal member 8A can be heated in a short time, the temperature rise of the first electrode 51 to the sixth electrode 56 (see FIG. 2A) can be suppressed as compared with the case where a conventional quadrilateral metal member is used.

  In addition, since the metal member 8A has the circular loop portion 18, the metal member 8A has a disk member having a disk portion having the same outline as the circular loop portion 18, instead of the circular loop portion 18. Smaller than when used. Therefore, the metal member 8A can be heated in a short time. Further, the peak value (high frequency output) of the high frequency voltage to be supplied to the external coil 97 can be reduced. Thereby, the temperature rise of the 1st electrode 51-the 6th electrode 56 can be suppressed rather than the case where the metal member which has a disk part is used.

  Here, an embodiment of a color picture tube will be described. As the two metal members 8A and 8B shown in FIGS. 3A and 3B, a stainless steel ribbon having a thickness of about 0.2 mm before forming the two metal deposition films 9A and 9B is used. .

  In the electron gun sealed in the color picture tube of one embodiment, as shown in FIG. 2 (A) or (B), the three cathodes 50R, 50G (not shown) and 50B are approximately horizontal. They are arranged in a line at equal intervals of 5 mm. Further, the first electrode 51 and the second electrode 52 are opposed to each other with a very narrow space of 0.5 mm or less, and two neighboring electrodes from the third electrode 53 to the sixth electrode 56 are 0.5 It is made to oppose at intervals of about 1 mm. Each opening of the first electrode 51 and the second electrode 52 is a small opening having a diameter of 1 mm or less, and the opening on the second electrode 52 side of the third electrode 53 is larger in diameter than the opening of the second electrode 52. The opening on the fourth electrode side of the third electrode 53, the opening on both sides of the fourth electrode 54, and the opening on both sides of the sixth electrode 56 are comparatively about 4 to 6 mm in diameter. Use large apertures.

  FIG. 7 is an explanatory diagram for explaining a method of driving an electron gun according to an embodiment. Each of the three cathodes 50R, 50G, and 50B is supplied with a voltage obtained by superimposing a video signal voltage VR, VG, and VB corresponding to an image on a DC voltage of about 150V. The first electrode 51 is electrically grounded. The second electrode 52 and the fourth electrode 54 are electrically connected in the internal space of the neck portion 2A (see FIG. 2A), and each of the second electrode 52 and the fourth electrode 54 has a DC voltage of about 700V. Supply. The third electrode 53 and the fifth electrode 55 are electrically connected in the internal space of the neck portion 2A, and a DC voltage of about 6 to 9 kV is supplied to each of the third electrode 53 and the fifth electrode 55. An anode high voltage Eb of about 25 kV is supplied to each of the sixth electrode 56 and the shield cup 61.

  The cathode 50B is in a state in which electrons are easily emitted by heating by the heater 58B (see FIGS. 2A and 2B). When a cathode voltage of about 150 V or more is supplied to the cathode 50B, electrons are emitted from the cathode 50B. Is released. The electric field distribution formed between the cathode 50B and the second electrode 52 is controlled by the DC voltage supplied to the cathode 50B, the first electrode 51, and the second electrode 52, and from the first electrode 51 to the sixth electrode 56. An electron beam is generated so as to pass through the approximate center of the opening formed in each electrode. Similarly, electron beams are generated from the other two cathodes 50R and 50G.

  The electron beams emitted from each of the three cathodes 50R, 50G, and 50B are converged toward the first electrode 51 and diverge after forming a crossover in the vicinity of the second electrode 52. The diverging electron beam is preliminarily focused by a prefocus lens formed by the second electrode 52 and the third electrode 53. The electron beam that has passed through the prefocus lens is generated by the first auxiliary lens formed by the third electrode 53 and the fourth electrode 54 and the second auxiliary lens formed by the fourth electrode 54 and the fifth electrode 55. Further pre-focusing is performed. The electron beam that has passed through the second auxiliary lens is focused by the main lens formed by the fifth electrode 55 and the sixth electrode 56. As a result, a beam spot is finally formed on the phosphor screen 4 (see FIG. 1).

  In the above embodiment, the case where the metal member is a stainless steel ribbon having a thickness of about 0.2 mm has been described. However, the metal member may be formed of other material thickness, other material, or the like.

  In the above description, the case where each of the two metal members 8A and 8B has the circular loop portion 18 has been described. However, the shape of the loop portion does not necessarily have to be a circle, and any shape that generates eddy currents can be used. Any shape may be used. Here, a modified example of the metal member will be described. 8A to 8C are schematic top views illustrating modifications of the metal member. As a modification of the metal member, a configuration having a polygonal loop portion 68 such as a square as shown in FIG. From the viewpoint of promoting the generation of eddy currents, the shape of the loop part is preferably a substantially regular polygon. Further, as a modification, a configuration having an elliptical or flat circular loop portion 78 as shown in FIG. 8B can be exemplified. As a modification, as shown in FIG. 8C, a loop portion 18 ′ formed by welding two metal ribbons 88 and 98 and two connection portions 28 ′ and 38 ′. The structure which has can be illustrated. In addition, the center of the x mark of the broken line in FIG.8 (C) represents the welding location of two metal ribbons. Welding for forming the loop portion 18 'is performed in a process of manufacturing a metal member, a process of connecting the metal member to an electrode, or the like.

  In the above description, the case where each of the two metal members 8A and 8B has the two linear connection portions 28 and 38 has been described. However, the connection portion has any shape as long as the loop portion and the electrode can be connected. It may be. Note that, from the viewpoint of reducing the heat capacity of the metal member, the connecting portion preferably has a thin linear shape that connects the loop portion and the electrode at the shortest distance. The metal member may have only a loop portion, and the loop portion may be directly connected to the electrode.

  In the above description, the case where the two metal members 8A and 8B are connected to the fourth electrode 54 has been described. However, the metal member is connected to any electrode constituting the electron gun other than the cathode and the anode. Also good.

  INDUSTRIAL APPLICABILITY The present invention can be used in a color picture tube in order to improve withstand voltage characteristics and suppress degradation of resolution.

FIG. 1 is a schematic partial plan view showing a structural example of a color picture tube according to the present invention. FIG. 2A is a schematic side view partially showing a structural example in the vicinity of the neck portion in the color picture tube according to the present invention, and FIG. 2B is a schematic top view thereof. . FIG. 3A is a schematic front view showing a structural example in the vicinity of the fourth electrode of the electron gun in the color picture tube according to the present invention, and FIG. 3B is a schematic top view thereof. . 4A to 4C are explanatory diagrams for explaining an example of a process for producing a metal member in the color picture tube according to the present invention by press working. FIGS. 5A and 5B are explanatory views for explaining another example of the process of manufacturing the metal member in the color picture tube according to the present invention by etching. FIG. 6A is a schematic side view showing the vicinity of the fourth electrode in order to explain the step of forming a conductive film in the method of manufacturing a color picture tube according to the present invention, and FIG. It is the typical top view. FIG. 7 is an explanatory diagram for explaining a method of driving an electron gun in a color picture tube according to the present invention. 8A to 8C are schematic top views showing modifications of the metal member in the color picture tube according to the present invention. FIG. 9A is a schematic front view showing a structural example in the vicinity of a metal member in order to explain a process of forming a metal vapor deposition film in the manufacture of a conventional typical color picture tube. B) is a schematic top view thereof.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Panel 2 Funnel 2A Neck part 3 Sealing part 4 Phosphor screen 5 Electron gun 6 Deflection yoke (deflector)
7 Internal conductive film 8, 8A, 8B Metal member 9, 9A, 9B Metal evaporated film (conductive film)
DESCRIPTION OF SYMBOLS 10 Stem pin 11 Beam generation part 12 Main lens part 18, 18 ', 68, 78 Loop part 28, 28', 38, 38 'Connection part 50R, 50G, 50B Cathode 51 1st electrode 52 2nd electrode 53 3rd electrode 54 Fourth electrode (electrode)
55 5th electrode 56 6th electrode (final acceleration electrode)
57, 57A, 57B Insulating support 58R, 58G, 58B Heater 61 Shield cup 62 Contact element 91, 92 Mold 93, 93'93A, 93B Metal base 96 Etching solution 97 External coil 108A, 108B Metal member 109A, 109B Metal Deposition film 197 External coil

Claims (7)

An envelope provided with a panel, a funnel having a neck portion, and a sealing portion;
A phosphor screen formed on the inner wall of the panel;
An internal conductive film formed on the inner wall of the funnel;
It has three cathodes and a plurality of electrodes arranged in a row, has a beam generator for generating three electron beams, a plurality of electrodes and an anode, and focuses each of the three electron beams on the phosphor screen. A color picture tube including a main lens unit to be formed, and an electron gun provided in an internal space of the neck unit, including an insulating support that supports the beam generation unit and the main lens unit,
A metal member connected to at least one of the plurality of electrodes of the beam generating portion and the plurality of electrodes of the main lens portion so as to cover a part of the insulating support, and having a loop-shaped loop portion; ,
A color picture tube, further comprising a conductive film formed in a region of the inner wall of the neck portion facing the metal member and spaced apart from the internal conductive film.   The color picture tube according to claim 1, wherein the loop portion of the metal member is disposed on a plane substantially parallel to a plane including a tube axis and an arrangement direction of three cathodes.   The color picture tube according to claim 1, wherein the loop portion of the metal member is disposed on the insulating support of the electron gun. Forming a phosphor screen on the inner wall of the face panel;
Forming an internal conductive film on the inner wall of the funnel having a neck portion;
Bonding the face panel and the funnel after forming the phosphor screen and the internal conductive film;
A beam generating unit that generates three electron beams, a main lens unit that controls focusing of each of the three electron beams; Producing an electron gun comprising an insulating support that supports a beam generating portion and the main lens portion;
Producing a metal member;
Fixing the metal member to at least one of the plurality of electrodes of the beam generating unit and the plurality of electrodes of the main lens unit so as to cover a part of the insulating support;
After fixing the metal member to the electron gun, the electron gun is disposed in the internal space of the neck portion, and the sealing portion and the funnel are joined, so that the electron gun is placed in the internal space of the neck portion. Sealing, and
A method of manufacturing a color picture tube, comprising: sealing the electron gun and then depositing a substance constituting the metal member on an inner wall of the neck portion by high-frequency heating using an external coil to form a conductive film. Because
The metal member has a loop portion having a loop shape,
In the step of forming the conductive film, an eddy current is generated along the loop portion.   5. The method of manufacturing a color picture tube according to claim 4, wherein, in the step of forming the conductive film, a central axis of the external coil and a central axis of the loop portion are substantially matched.   5. The method of manufacturing a color picture tube according to claim 4, wherein in the step of producing the metal member, the metal member is produced by pressing.   The method of manufacturing a color picture tube according to claim 4, wherein in the step of manufacturing the metal member, the metal member is manufactured by etching.

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