JP2006140137A - Color cathode-ray tube and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress convergence drift of three electron beams, and improve color purity. <P>SOLUTION: A conductive film 6 is formed on the inner wall of a neck portion. When the position in the tube axial direction at the anode side edge of an anode side focusing electrode 14E located nearest the anode 15 side out of a plurality of focusing electrodes constituting an electron gun is made P0, the position in the tube axial direction at the beam generation part side edge of the electrode located nearest the beam generation part side out of the electrodes which are applied with approximately the same voltage as the anode side focusing electrode 14E and are arranged continued from the anode side focusing electrode 14E is made P1, and in the tube axial direction, the position at the beam generation part side edge of the conductive film 6 is made PL1, and the position at the panel side edge is made PL2, P0 is located between PL1 and PL2. When the distance from P0 to PL1, PL2, and P1 are made L1, L2, and L3, L1>L2 and L1<L3 are satisfied. In the vertical direction, the range occupied by the conductive film 6 includes the range occupied by the positive electrode side focusing electrode 14E, and is larger than this. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color cathode ray tube and a manufacturing method thereof. More specifically, the present invention relates to a technique for improving the stability of convergence of three electron beams in a color cathode ray tube.

  A conventional color cathode ray tube includes a glass bulb (envelope) having a funnel composed of a funnel portion and a neck portion, and a panel, and the internal space of the glass bulb is kept in a vacuum state. A phosphor screen is formed on the inner wall of the panel. An electron gun is built in the neck. A deflector for deflecting the electron beam emitted from the electron gun is provided on the outer peripheral surface of the funnel portion. In addition, an internal conductive film electrically connected to the anode is formed on part of the funnel portion and the neck portion.

  The electron gun takes out an electron beam and controls a beam shape, and includes a first electrode group (beam generation unit) and a second electrode group (a plurality of focusing electrodes) for finally focusing the electron beam on a phosphor screen. And an anode). Usually, an electron gun emits three electron beams arranged in a line consisting of a central electron beam and two side electron beams on both sides thereof. In a color cathode ray tube, the three electron beams converge on the phosphor screen, and each of the three electron beams is focused on the phosphor screen. However, the convergence state of the three electron beams changes with time due to the change with time of the potential of the inner wall of the neck portion (hereinafter also referred to as “neck potential”). As a result, color misregistration occurs. More specifically, the neck potential usually has a potential distribution depending on the position of the neck portion, and this forms an electric field (hereinafter also referred to as “penetration electric field”) that penetrates each gap between the electrodes of the electron gun. Since the electric field acting on each electron beam is a combined electric field formed by each electrode and a penetrating electric field that depends on the neck potential, if the penetrating electric field changes, the composite electric field changes and the trajectory of each electron beam changes. Will change. In particular, the two side electron beams are easily affected by changes in the penetration electric field, so that their trajectories change more greatly than the central electron beam. As a result, the landing position of the three electron beams is deviated, causing convergence drift, leading to color misregistration.

  Here, the reason why the penetration electric field changes will be described. The neck potential immediately after applying a predetermined voltage to each electrode is that the inner conductive film having the same potential as the anode is formed on the inner wall of the glass bulb. Potential distribution in which the potential decreases toward the opposite end of the panel. However, as time passes, stray electrons generated in the internal space of the neck portion collide with the inner wall of the neck portion, and more secondary electrons than the number of colliding floating electrons are emitted from the neck portion. Gradually increase the potential. As a result, the composite electric field acting on each electron beam changes with time.

As a technique for reducing the convergence drift due to the change of the penetration electric field, the gap between two electrodes (focusing electrodes) other than the electrode (anode) to which the highest voltage is applied among the electrodes constituting the second electrode group and the horizontal direction There is known a configuration in which a conductive film is attached to a region on the inner wall of the neck portion facing (see, for example, Patent Document 1). The horizontal direction is the same as the arrangement direction of the three electron beams. Hereinafter, this configuration is referred to as a “conventional example”.
Japanese Patent Laid-Open No. 10-188843

  In the above-described conventional example, the conductive film is formed in a region on the inner wall of the neck portion facing the gap between the focusing electrodes in the horizontal direction, but the focusing electrode closest to the anode (hereinafter referred to as “anode-side focusing electrode”). ”) And the anode, the effect of reducing the convergence drift was small. This is because the penetration electric field into the gap between the electrodes constituting the second electrode group contributes most to the convergence drift because of the penetration electric field into the gap between the anode-side focusing electrode and the anode. . The reason is as follows. First, since the region on the inner wall of the neck portion facing the anode-side focusing electrode is close to the internal conductive film, it is charged to a relatively high potential. Therefore, the strength of the penetration electric field into the gap between the anode-side focusing electrode and the anode is large and the change is large. Second, a main lens is formed between the anode-side focusing electrode and the anode by applying a predetermined voltage to each electrode. This is because if the electric field distribution constituting the main lens changes due to the penetration electric field, even if the change in the electric field distribution constituting the lens between other electrodes can be suppressed, convergence drift occurs.

  As a method of reducing the influence of the penetration electric field on the gap between the anode-side focusing electrode and the anode, it is conceivable to reduce the gap between the electrodes, but withstand voltage such as the occurrence of sparks between these electrodes. This is not preferable because the characteristics deteriorate.

  Therefore, in the present invention, the convergence drift is suppressed and the color purity of the color display is improved without degrading the withstand voltage characteristic between the anode-side focusing electrode and the anode. In the present invention, the method of manufacturing a color cathode ray tube is improved in order to increase the color purity of color display.

  A color cathode ray tube according to the present invention is provided in a funnel including a funnel portion and a neck portion, an envelope having a panel, a phosphor screen provided on the inner wall of the panel, and an inner space of the neck portion. A beam generator for controlling generation of three electron beams arranged in an in-line direction, an electron gun including a plurality of focusing electrodes and an anode for controlling focusing of the three electron beams, an inner wall of the funnel portion, and the neck portion And an inner conductive film formed on a part of the inner wall and electrically connected to the anode. The color cathode ray tube according to the present invention further includes a conductive film spaced apart from the internal conductive film on the inner wall of the neck portion.

  Of the plurality of focusing electrodes, the position of the anode-side focusing electrode located closest to the anode side in the tube axis direction of the anode-side end is P0, substantially the same voltage as the anode-side focusing electrode is applied, and the anode Of the electrodes arranged continuously from the side focusing electrode, the position of the electrode located closest to the beam generator side in the tube axis direction at the end of the beam generator side is P1, and in the tube axis direction, the conductive film When the position of the beam generation unit side end is PL1, and the position of the panel side end is PL2, the position P0 is located between the position PL1 and the position PL2 in the tube axis direction.

The distance in the tube axis direction from the position P0 to the position PL1 is L1, the distance in the tube axis direction from the position P0 to the position PL2 is L2, and the distance in the tube axis direction from the position P0 to the position P1 is L3. When
L1> L2
L1 <L3
Satisfied.

  In the direction perpendicular to the tube axis and the in-line direction, the range occupied by the conductive film includes and is larger than the range occupied by the anode-side focusing electrode.

  The method of manufacturing a color cathode ray tube according to the present invention includes a step of forming a phosphor screen on the inner wall of the panel (phosphor screen forming step), and an inner conductive film on the inner wall from the funnel portion to a part of the neck portion in the funnel. A step (inner conductive film forming step), a step of bonding the panel and the funnel to form an envelope (envelope forming step), a beam generator, a plurality of focusing electrodes and an anode. A step of fixing the provided electron gun in the internal space of the neck portion (electron gun fixing step), and an exhausting step of sealing the internal space of the envelope by reducing the pressure.

  In the method of manufacturing a color cathode ray tube according to the present invention, the anode-side focusing electrode is configured by heating the anode-side focusing electrode located closest to the anode among the plurality of focusing electrodes after the exhausting step. The method further includes a heating step of depositing a material to be deposited on the inner wall of the neck portion to form a conductive film separated from the internal conductive film.

  The color cathode ray tube of the present invention has a region on the inner wall of the neck portion (that is, the main lens forming region and the tube) facing the gap between the anode-side focusing electrode and the anode (hereinafter also referred to as “main lens forming region”). A region on the inner wall of the neck portion having the same axial position (hereinafter also referred to as “main lens facing region”) is provided with a conductive film. The conductive film formation region is defined in association with the focusing electrode. Thereby, the convergence drift of 3 electron beams can be suppressed and the color purity in color display can be improved.

  In addition, according to the method of manufacturing a color cathode ray tube of the present invention, since a conductive film can be formed in the main lens facing region, the convergence drift of three electron beams is suppressed, and the color cathode ray with improved color purity in color display. Tubes can be manufactured.

  As described above, the color cathode ray tube according to the present invention includes an envelope having a funnel including a funnel portion and a neck portion, and a panel, a phosphor screen, a beam generating portion, a plurality of focusing electrodes, and an anode. An electron gun, an internal conductive film, and a conductive film separated from the internal conductive film are included. The color cathode ray tube according to the present invention further includes a deflector that deflects an electron beam by an electric action or a magnetic action, a shadow mask that performs color selection, a magnetic shield that reduces disturbance due to geomagnetism in the orbit of the electron beam, and the like. May be included. The color cathode ray tube according to the present invention may be the same as any known configuration except for the conductive film.

  The conductive film is formed in the main lens facing region. More precisely, in the tube axis direction, the position P0 related to the anode-side focusing electrode defined as described above is located between the position PL1 and the position PL2 related to the conductive film. Furthermore, regarding the formation region in the tube axis direction of the conductive film, L1> L2 and L1 <L3 are satisfied. Thereby, the emission gain of secondary electrons to the conductive film (the number of secondary electrons emitted when one electron collides) becomes smaller than that of the neck portion itself (insulating material), etc. It is possible to suppress a change with time of the potential of the inner wall facing region of the main lens. As a result, the temporal change in the convergence state of the three electron beams can be suppressed, and the occurrence of color misregistration can also be suppressed.

  Moreover, regarding the direction (circumferential direction) around the tube axis, the conductive film may be formed over the entire circumference or may be formed partially. However, in the direction orthogonal to the tube axis and the in-line direction (hereinafter referred to as “vertical direction”), the range occupied by the conductive film includes the range occupied by the anode-side focusing electrode and is larger than this. A region on the inner wall of the neck portion facing the anode-side focusing electrode in the in-line direction (hereinafter referred to as “horizontal direction”) has a short distance to the anode-side focusing electrode. Therefore, if a conductive film is formed in a region including this region on the inner wall of the neck portion, the potential of the conductive film is stabilized at a value close to the potential of the anode-side focusing electrode. The amount is reduced and the convergence drift can be reduced.

  When the conductive film is formed only on a part of the inner wall of the neck portion in the circumferential direction, it is preferable that the conductive film is formed in a region on the inner wall of the neck portion that faces the main lens forming region in the horizontal direction. This is because the side electron beam passes closer to the region facing the horizontal direction than the region facing the main lens forming region in the vertical direction on the inner wall of the neck portion.

  The conductive film is preferably formed on the entire surface of the main lens facing region. That is, the conductive film is formed over the entire circumference in the circumferential direction, and in the tube axis direction, the position PL1 of the beam generation unit side end generates a beam with respect to the position P0 of the anode side end of the anode side focusing electrode. It is preferable that the position PL2 of the panel side end is located on the panel side with respect to the position of the focusing electrode side end of the anode. According to this preferable configuration, it is possible to suppress a change in neck potential with time in the entire main lens facing region. Note that the range occupied by the conductive film in the tube axis direction and the range occupied by the anode in the tube axis direction may overlap, but in this case, sparks are likely to occur between the conductive film and the anode. Therefore, it is preferable that the overlapping width in the tube axis direction of both is as small as possible.

  In the color cathode ray tube according to the present invention, the conductive film is preferably a metal vapor deposition film. If the conductive film is a metal film, the film thickness of the conductive film can be reduced because the conductivity is higher than that of a conductive film formed using another substance. In addition, if the conductive film is a deposited film, a material for forming the conductive film is disposed in the inner space of the envelope, and after performing an exhaust process for reducing the pressure in the inner space of the envelope, This is because it can be easily formed by vacuum deposition. The material for forming the metal vapor deposition film may be a part of the anode-side focusing electrode, or may be a conductor such as a metal foil or a metal ribbon separately provided on the anode-side focusing electrode. .

  In the color cathode ray tube according to the present invention, the gap between the anode-side focusing electrode and the anode is preferably 1.0 mm or more. With this configuration, the withstand voltage characteristic between the anode-side focusing electrode and the anode can be improved. The gap between the anode-side focusing electrode and the anode is preferably 2.0 mm or less. Furthermore, the gap is preferably in the range of 1.0 mm to 1.5 mm.

  As described above, the method for manufacturing a color cathode ray tube according to the present invention includes a phosphor screen forming step, an internal conductive film forming step, an envelope forming step, an electron gun fixing step, an exhausting step, and a heating step. Including. When manufacturing a color cathode ray tube further including a deflector, a shadow mask, a magnetic shield, etc., it further includes a process of manufacturing and assembling them. In the method for manufacturing a color cathode ray tube according to the present invention, any known technique may be used in steps other than the heating step for forming the conductive film. According to this manufacturing method, the conductive film can be easily and reliably formed. In the heating step, any known method may be used for heating the anode-side focusing electrode. The conductive film formed by the heating process may include only the material that has formed the anode-side focusing electrode, or may further include the material that has formed the other electrode such as the anode. This manufacturing method is a method for manufacturing the color cathode ray tube of the present invention. The color cathode ray tube of the present invention is manufactured by another manufacturing method as long as a conductive film is formed at a predetermined position. Also good.

  In the method for manufacturing a color cathode ray tube according to the present invention, in the heating step, the heating is preferably high-frequency heating using an external coil. If this method is applied, the anode-side focusing electrode can be efficiently heated to a higher temperature than the other electrodes. Further, the surface of the anode-side focusing electrode facing the neck portion (hereinafter also referred to as “outer surface”) can be selectively heated.

  In the method for manufacturing a color cathode ray tube according to the present invention, in the heating step, the maximum temperature Tmax (see FIG. 6) of the anode-side focusing electrode is preferably in the range of 900 ° C. or higher and 1100 ° C. or lower. In the present invention, the temperature of the anode-side focusing electrode means the temperature at the highest temperature portion on the outer surface of the anode-side focusing electrode. Therefore, the maximum temperature Tmax of the anode-side focusing electrode in the heating process means the highest temperature among the temperatures at the outer surface portion of the anode-side focusing electrode that shows the maximum temperature at each time point in the heating process. If this method is applied, the substance which comprises an anode side focusing electrode can be efficiently vapor-deposited on the inner wall of a neck part, suppressing the change of the position and shape of an anode side focusing electrode.

  If the maximum temperature Tmax of the anode-side focusing electrode is less than 900 ° C., it is difficult for the material constituting the anode-side focusing electrode to evaporate from the surface. Therefore, it takes a long time to form a conductive film having a desired film thickness. Cost. If heating is performed for a long time, the temperature of an insulating holding member such as bead glass that holds the anode-side focusing electrode is likely to rise, and the position of the anode-side focusing electrode is likely to shift. On the other hand, when the maximum temperature Tmax exceeds 1100 ° C., the temperature of the member disposed near the anode-side focusing electrode rises due to a leakage magnetic field or radiant heat, and the characteristics of the member are deteriorated. In addition, since the insulating holding member is easily heated to the melting point or higher, the position of the anode-side focusing electrode is easily displaced. Therefore, the maximum temperature Tmax of the anode-side focusing electrode is preferably within the above range. Furthermore, the maximum temperature Tmax is preferably in the range of 900 ° C. or higher and 950 ° C. or lower.

  In the method of manufacturing a color cathode ray tube according to the present invention, in the heating step, a value obtained by integrating a difference temperature obtained by subtracting 900 ° C. from the temperature of the anode-side focusing electrode over the entire time when the temperature of the anode-side focusing electrode satisfies 900 ° C. or more. Is preferably in the range of 0 ° C. · sec to 2500 ° C. · sec. Thereby, it is possible to form a conductive film having an optimum film thickness while suppressing changes in the position and shape of the anode focusing electrode.

(Embodiment 1)
In the first embodiment, a specific example of a color cathode ray tube according to the present invention will be described. FIG. 1 is a schematic cross-sectional view showing an example of the overall structure of a color cathode ray tube.

As shown in FIG. 1, the color cathode ray tube includes an envelope having a funnel 2 including a funnel portion 2A and a neck portion 2B, and a panel 1, and a phosphor screen 3 formed on the inner wall of the panel 1. The electron gun 4 formed in the inner space of the neck portion 2B, the inner conductive film 5 formed on the inner wall of the funnel portion 2A and the inner wall of the neck portion 2A, and the inner wall of the neck portion 2B. The conductive film 6, the shadow mask 7, and a deflector (not shown) are included. The color cathode ray tube according to the present invention may be the same as any known color cathode ray tube except for the conductive film 6. The internal space of the envelope is kept in a vacuum state of about 1.33 × 10 ⁻³ Pa (10 ⁻⁵ Torr).

  FIG. 2 is a schematic partially cut side view showing an example of the structure in the vicinity of the electron gun of the color cathode ray tube. In FIG. 2, the upper side of the tube axis represented by the alternate long and short dash line represents a cross-sectional view, and the lower side represents a semi-transparent view.

  As shown in FIG. 2, the electron gun 4 includes three cathodes 11 (arranged in a direction perpendicular to the paper surface of FIG. 2), a control electrode 12, two acceleration electrodes 13A and 13B, and a plurality of focusing electrodes. 14A to 14E, an anode (final acceleration electrode) 15, and a shield cup 16. Each of these electrodes and the shield cup 16 is formed with an aperture through which three electron beams pass. The three cathodes 11, the control electrode 12, and the two acceleration electrodes 13A and 13B constitute a beam generation unit.

  Each electrode is fixed to a neighboring electrode at a predetermined interval by a pair of insulating holding portions 17 made of bead glass or the like. By applying a predetermined voltage to each electrode, the main lens 10 is formed in the gap between the focusing electrode 14 </ b> A to 14 </ b> E closest to the anode 15 (anode-side focusing electrode) 14 </ b> E and the anode 15. The The voltages applied to the electrodes are about 600 V for the two acceleration electrodes 13A and 13B, about 8 kV for the focusing electrodes 14A to 14E, and about 30.5 kV for the anode 15. Each of the three electron beams emitted from the electron gun 4 travels toward the phosphor screen 3 and is focused on the phosphor screen 3 (see FIG. 1).

  The anode-side focusing electrode 14E and the anode 15 are made of a stainless material. The width of the gap between the anode-side focusing electrode 14E and the anode 15 is 1.0 mm or more.

  The internal conductive film 5 is formed on the inner wall from the funnel portion 2A to the portion of the neck portion 2B facing the center of the shield cup 16 in the tube axis direction. The internal conductive film 5 is provided for applying a voltage to the anode 15 via the centering spring 18 and the shield cup 16. That is, the internal conductive film 5 and the anode 15 have substantially the same potential.

  The conductive film 6 is formed on a region including at least a part of the main lens facing region 19 on the inner wall of the neck portion 2B in the tube axis direction. Here, it should be noted that the conductive film 6 is separated from the internal conductive film 5.

  FIG. 3 is a schematic partial cut-away side view showing an example of the structure in the vicinity of the focusing electrode of the color cathode ray tube of the first embodiment. In FIG. 3, the upper side from the tube axis represented by the alternate long and short dash line represents a cross-sectional view, and the lower side represents a semi-perspective view. The range occupied by the conductive film 6 of the color cathode ray tube of the first embodiment in the tube axis direction will be described with reference to FIG.

  As illustrated, the position in the tube axis direction of the anode 15 side end of the anode-side focusing electrode 14E is P0. The tube at the beam generation unit side end of the focusing electrode 14B positioned closest to the beam generation unit among the electrodes that are applied with substantially the same voltage as the anode focusing electrode 14E and are continuously arranged from the anode side focusing electrode 14E. The position in the axial direction is P1. Here, the same voltage as that of the anode-side focusing electrode 14E is applied to the focusing electrode 14A (see FIG. 2), but an acceleration electrode to which a voltage different from that of the anode-side focusing electrode 14E is applied between the focusing electrode 14A and the anode-side focusing electrode 14E. Since 13B exists, it cannot be an electrode that defines the position P1. Note that “the electrodes are arranged continuously” includes both cases where the plurality of electrodes are adjacent to each other with a gap and where the plurality of electrodes are joined to each other.

  Further, in the tube axis direction, the position of the conductive film 6 on the side of the beam generation unit side is PL1, and the position of the panel side end is PL2.

  In the present embodiment, the position P0 is located between the position PL1 and the position PL2 in the tube axis direction.

  Furthermore, when the distance in the tube axis direction from the position P0 to the position PL1 is L1, the distance in the tube axis direction from the position P0 to the position PL2 is L2, and the distance in the tube axis direction from the position P0 to the position P1 is L3, L1> L2 and L1 <L3 are satisfied.

  Satisfying L1> L2 and L1 <L3 means that most of the conductive film 6 faces the anode-side focusing electrode 14E and an electrode to which the same voltage is applied. Therefore, the potential of the conductive film 6 is stabilized at a value close to the potential of the anode-side focusing electrode 14E. Therefore, the amount of change in the neck potential is reduced and the change in the penetration electric field to the main lens formation region is reduced, so that convergence drift can be suppressed.

  When L1 ≦ L2 is satisfied, more than half of the conductive film 6 faces the main lens formation region or the anode 15. Therefore, the potential of the conductive film 6 is stabilized at a value between the potential of the anode-side focusing electrode 14E and the potential of the anode 15. Therefore, the convergence drift increases.

  When L1 ≧ L3 is satisfied, the conductive film 6 faces the electrode to which a voltage different from that of the anode-side focusing electrode 14E is applied. Accordingly, the potential of the conductive film 6 becomes smaller than the potential of the anode-side focusing electrode 14E, disturbing the electric field in the main lens formation region, causing a focus failure. If the potential of the conductive film 6 is lower than the potential of the anode-side focusing electrode 14E, the potential difference between the conductive film 6 and the anode 15 becomes large, and discharge may occur between the two.

  4 is a cross-sectional view taken along line IV-IV perpendicular to the tube axis and passing through the main lens facing region 19 in FIG. The range occupied by the conductive film 6 of the color cathode ray tube of the first embodiment in the vertical direction will be described with reference to FIG. In the vertical direction, the range occupied by the conductive film 6 includes and is larger than the range occupied by the anode-side focusing electrode 14E. Thereby, the potential of the conductive film 6 is stabilized at a value close to the potential of the anode-side focusing electrode 14E. Therefore, the amount of change in the neck potential is reduced and the change in the penetration electric field to the main lens formation region is reduced, so that convergence drift can be suppressed. In the present invention, the “range occupied by the anode-side focusing electrode 14E in the vertical direction” means a range occupied by the vertical dimension HE of the cylindrical portion of the anode-side focusing electrode 14E, and is embedded in the insulating holding portion 17. Protruding parts such as parts (eg lugs) are not considered. This is because the protruding portion has little influence on the neck potential.

  A method of manufacturing the color cathode ray tube according to the first embodiment will be described. FIG. 5 is a schematic cross-sectional view for explaining an example of a heating step in the method of manufacturing a color cathode ray tube. Note that steps other than the heating step will be described with reference to FIG. 1 for convenience.

  The panel 1, the funnel 2 having the funnel portion 2A and the neck portion 2B, and the electron gun 4 are prepared in advance. A phosphor screen 3 is formed on the inner wall of the manufactured panel 1 (phosphor screen forming step). Moreover, the internal conductive film 5 is formed on the inner wall of the manufactured funnel 2 (internal conductive film forming step). After completing the phosphor screen forming step and the inner conductive film forming step, the panel 1 and the funnel 2 are joined to form an envelope (envelope forming step). After completing the envelope forming step, the electron gun 4 is fixed in the internal space of the neck portion 2B of the envelope (electron gun fixing step). After completing the electron gun fixing step, the inner space of the envelope is decompressed and sealed (exhaust step).

  After completing the exhaust process, as shown in FIG. 5, the coil (external coil) 20 is disposed so as to surround at least a part of the anode-side focusing electrode 14E of the electron gun 4 from the outside of the neck portion 2B, A high frequency current is passed through the coil 20 (heating step). Here, the heating time condition in the heating step will be described with reference to FIG. FIG. 6 is a graph showing an example of the transition of the temperature of the anode-side focusing electrode 14E with respect to the heating time. In FIG. 6, the heating time means not the time for flowing current but the time from when the current starts to flow until the anode-side focusing electrode 14E returns to room temperature.

  In the heating process, as shown in FIG. 6, it is preferable to control the value of the current flowing through the coil 20 so as to satisfy the following two conditions. The first condition is that the maximum temperature of the anode-side focusing electrode 14E is 900 ° C. or higher and 1100 ° C. or lower (heating condition 1). The second condition is a value obtained by integrating the differential temperature obtained by subtracting 900 ° C. from the temperature of the anode-side focusing electrode 14E over the entire heating time in which the temperature of the anode-side focusing electrode 14E satisfies 900 ° C. or more (the shaded area in FIG. 6). The area S) is 0 ° C. · sec to 2500 ° C. · sec (heating condition 2).

  In the heating process, the shape of the coil 20 is not particularly limited. Moreover, since the site | part with the highest temperature in the outer surface of the anode side focusing electrode 14E changes according to the shape of the coil 20 and arrangement | positioning of the coil 20, it is preferable to optimize them.

  In the heating step, the temperature of the anode 15 is preferably maintained at 900 ° C. or lower. When the temperature exceeds 900 ° C., evaporation of the material constituting the anode 15 also starts from the anode 15, and a conductive film is formed in a region facing the anode 15 on the inner wall of the neck portion 2 B, which easily causes a breakdown voltage characteristic failure. It is. Further, the temperature of the centering spring 18 attached to the shield cup 16 is preferably maintained at 570 ° C. or lower. This is because if the temperature exceeds 570 ° C., the spring characteristics of the centering spring 18 deteriorate. If the temperature of the anode-side focusing electrode 14E exceeds 1100 ° C., the temperature of the centering spring 18 may exceed 570 ° C. due to the leakage magnetic field from the coil 20 or the radiant heat from the anode-side focusing electrode 14E.

  After the exhaust process is completed, in order to improve the degree of vacuum in the inner space of the envelope, as in the case of manufacturing a known color cathode ray tube, a getter flash process that performs high-frequency heating with a coil, between the electrodes during operation A withstand voltage treatment step for suppressing the generation of leakage current, and a cathode activation step for heating the cathode 11 with a heater or the like and applying a voltage between the cathode 11 and the control electrode 12 to thermally activate the cathode. . There is no restriction | limiting in particular in the order between these processes and said heating process. Through the above steps, the color cathode ray tube according to Embodiment 1 shown in FIG. 1 is completed.

  In the color cathode ray tube of the first embodiment, it is preferable that the conductive film 6 is formed on the entire surface of the main lens facing region 19. Thereby, emission of secondary electrons from the main lens facing region 19 can be suppressed. Therefore, an increase in potential of the main lens facing region 19 can be suppressed. As a result, the temporal change in the convergence state of the three electron beams can be satisfactorily suppressed, and the occurrence of color misregistration can be satisfactorily suppressed.

  In addition, since the conductive film 6 is provided in the main lens facing region 19, the control is performed in order to stabilize the potential of the inner wall of the neck portion 2B in the region closer to the cathode 11 than the region where the conductive film 6 is formed. Sparks from the electrode 12, the acceleration electrode 13A, and the like can be suppressed. Furthermore, since the width of the gap between the anode-side focusing electrode 14E and the anode 15 can be increased, the withstand voltage characteristic can also be improved.

  According to said manufacturing method, compared with the case where the conductor for forming an electrically conductive film is provided in an electron gun like the comparative example 1, comparative example 2, and Embodiment 3 mentioned later, the material of an electrically conductive material The cost can be reduced and the process of attaching the conductor can be reduced. Further, when the conductor is provided in the electron gun, there is a large variation in the attachment position of the conductor, and the conductor may or may not contact the electrode. As a result, when the conductor is heated, the amount of heat leaked from the conductor to the electrode varies, the accuracy of forming the conductive film is lowered, and the effect of suppressing convergence drift is deteriorated. However, according to the above manufacturing method, it is possible to prevent deterioration of the effect of suppressing the convergence drift due to a decrease in the accuracy of forming such a conductive film.

  In the above description, the anode-side focusing electrode 14E and the anode 15 are made of stainless steel, but may be made of a material other than stainless steel. Since the temperature at which the constituent material evaporates varies depending on the material of the anode-side focusing electrode 14E, the maximum temperature of the anode-side focusing electrode 14E in the heating process is preferably optimized according to the material. In addition, since the evaporation amount of the constituent material changes depending on the material of the anode-side focusing electrode 14E, it is preferable that the temperature transition of the anode-side focusing electrode 14E in the heating process is optimized according to the material.

  Hereinafter, an example (hereinafter referred to as “example”) of the color cathode ray tube according to the first embodiment will be described. The color cathode ray tube of the embodiment is a 32-inch type color cathode ray tube. The conductive film 6 was formed through the temperature transition shown in FIG. The width of the gap between the anode-side focusing electrode 14E and the anode 15 was 1.2 mm.

  In the tube axis direction, the position P0 related to the anode-side focusing electrode 14E was located between the position PL1 and the position PL2 related to the conductive film 6. The distances L1, L2, and L3 shown in FIG. 3 were 6 mm, 2 mm, and 30 mm in this order. In the vertical direction, the range occupied by the anode-side focusing electrode 14E (dimension HE in FIG. 4) was 10 mm, and the range occupied by the conductive film 6 (dimension HL in FIG. 4) was 18 mm. In the vertical direction, the range occupied by the conductive film 6 completely included the range occupied by the anode-side focusing electrode 14E.

  For comparison, in place of the conductive film 6 of the embodiment, a conductive film is provided in a region on the inner wall of the neck portion 2B that is perpendicular to the joint between the focusing electrode 14B and the focusing electrode 14C. A color cathode ray tube of Comparative Example 1 which is the same as the above example was manufactured.

  Further, instead of the conductive film 6 of the embodiment, a conductive film 36 (see FIG. 9 described later) is provided in a region on the inner wall of the neck portion 2B that faces the gap between the focusing electrode 14C and the focusing electrode 14D in the horizontal direction. A color cathode-ray tube of Comparative Example 2 that was the same as the above example was manufactured except that it was provided (see Patent Document 1).

  Further, with respect to the range occupied by the conductive film 6 in the tube axis direction, a color cathode ray tube of Comparative Example 3 was manufactured which was the same as the above example except that the distances L1 and L2 shown in FIG. .

  A method for manufacturing the color cathode ray tube of Comparative Example 1 will be described. Similarly to the example, the panel 1, the funnel 2 having the funnel portion 2A and the neck portion 2B, and the electron gun 4 were respectively prepared in advance. Furthermore, a metallic ribbon (conductor) made of stainless steel or the like was prepared in advance. As in the example, a phosphor screen forming step, an internal conductive film forming step, and an envelope forming step were performed.

  FIG. 7 is an explanatory diagram for explaining a process of attaching a metal ribbon (conductor) on the electron gun. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. As shown in FIGS. 7 and 8, the pair of bead glasses (insulating holding portions) 17 arranged in the vertical direction with the focusing electrode 14B interposed therebetween, and the lugs 22A and 22B of the focusing electrode 14B A pair of metal ribbons 21 is provided on the focusing electrode 14B so as to connect the two (conductor attachment step). After completing the envelope forming step and the conductor attaching step, the electron gun fixing step and the exhaust step were performed as in the example.

  After the exhaust process was completed, the coil was disposed so as to surround the focusing electrode 14B of the electron gun from the outside of the neck portion 2B, and a high-frequency current was passed through the coil (heating process). Thereby, the pair of metal ribbons 21 was heated at high frequency. In the heating step of Comparative Example 1, the center of the coil in the tube axis direction was matched with the center of the pair of metal ribbons 21 in the tube axis direction. After the exhaust process was completed, a getter flash process, a pressure resistance process process, a cathode activation process, and the like were performed as in the example. The color cathode ray tube of Comparative Example 1 was manufactured through the above steps.

  A method for manufacturing the color cathode ray tube of Comparative Example 2 will be described. FIG. 9 is an explanatory diagram for explaining a process of attaching a metal ribbon (conductor). As shown in FIG. 9, the color cathode ray tube of Comparative Example 2 is the same as that of Comparative Example 1 except that a pair of metal ribbons (conductors) 31 are attached to both side surfaces of the focusing electrode 14D in the horizontal direction. Manufactured according to the manufacturing method. Thereby, the conductive film 36 was formed in the color cathode ray tube of the comparative example 2.

  A method for manufacturing the color cathode ray tube of Comparative Example 3 will be described. The color cathode ray tube of Comparative Example 3 was manufactured according to the same manufacturing method as in the Examples except for the size and position of the coil in the heating process. The heating process of Comparative Example 3 will be described. The dimension in the tube axis direction of the coil used in Comparative Example 3 was 3/4 of the dimension in the tube axis direction of the coil 20 used in the example. In Comparative Example 3, the position of the coil in the tube axis direction was adjusted so that the position of the panel side end of the coil substantially coincided with the position of the joining surface between the anode 15 and the shield cup 16 in the tube axis direction. The position of the coil side end of the coil in Comparative Example 3 in the tube axis direction was shifted to the panel side by about 5 mm from that in the example. Except for the above, the heating process was performed by applying a high-frequency current to the coil in the same manner as in the example. As a result, conductive films having distances L1 and L2 shown in FIG. 3 of 2 mm and 3 mm in order were formed.

  The convergence drift in the three types of color cathode ray tubes of Example, Comparative Example 1, and Comparative Example 2 will be described. FIG. 10 is a graph showing the relationship between the voltage application time to each electrode of each color cathode-ray tube of Examples and Comparative Examples 1 and 2 and the amount of convergence drift. In FIG. 10, an Example is represented by a solid line, Comparative Example 1 is represented by a one-dot chain line, and Comparative Example 2 is represented by a broken line. The amount of convergence drift was measured at the center of the phosphor screen (near the intersection of the phosphor screen and the tube axis). As shown in FIG. 10, the convergence drift amount was 0.02 mm in the example. On the other hand, it was 0.3 mm in Comparative Example 1, and 0.2 mm in Comparative Example 2. As can be seen from FIG. 10, in the color cathode ray tube of the example, the convergence drift over time was satisfactorily suppressed.

  Further, as a result of observing the color misregistration of the three types of color cathode ray tubes, no color misregistration occurred on the entire surface of the phosphor screen in the example, and color misregistration occurred in Comparative Examples 1 and 2.

  Convergence drift in the two types of color cathode ray tubes of Example and Comparative Example 3 will be described. FIG. 11 is a graph showing the relationship between the voltage application time to each electrode of each color cathode ray tube of Example and Comparative Example 3 and the amount of convergence drift. In FIG. 11, an Example is represented by a solid line and Comparative Example 3 is represented by a broken line. The amount of convergence drift was measured at the center of the phosphor screen. As shown in FIG. 11, the convergence drift amount was 0.02 mm in the example. On the other hand, in Comparative Example 3, it was 0.15 mm. As can be seen from FIG. 11, the convergence drift was better suppressed in the color cathode ray tube of the example than in the color cathode ray tube of the comparative example 3. The difference between the two is due to the difference in potential of the conductive film. In the embodiment, since most of the conductive film 6 in the tube axis direction faces the anode-side focusing electrode 14E, the potential of the conductive film 6 is stabilized at a potential close to the anode-side focusing electrode 14E. On the other hand, in Comparative Example 3, most of the conductive film in the tube axis direction faces the main lens formation region and the anode 15, so that the potential of the conductive film is the potential of the anode-side focusing electrode 14 </ b> E and the potential of the anode 15. Stable at a potential close to the middle of the potential. In Example and Comparative Example 3, a difference in convergence drift occurs due to such a difference in potential of the conductive film.

  In the first embodiment, a color cathode ray tube equipped with a static focus type electron gun having a constant focus voltage has been described with reference to an example. However, the color cathode ray tube of the present invention changes in synchronization with a deflection magnetic field. A dynamic focus type electron gun that applies a dynamic focus voltage on which an AC component is superimposed to the focusing electrode may be mounted. This will be described with reference to FIG.

  In the case of a dynamic focus type electron gun, normally, a static focus voltage Vfoc1 is applied to the focusing electrodes 14B and 14C, and an alternating current that changes to the static focusing voltage Vfoc2 in synchronization with the deflection magnetic field is applied to the focusing electrodes 14D and 14E. A dynamic focus voltage on which the component Vd is superimposed is applied. As a result, a dynamic focus lens is formed between the focusing electrode 14C and the focusing electrode 14D. The voltage Vg2 applied to the accelerating electrode 13B is about 600V, and the voltage Vfoc1 applied to the focusing electrodes 14B and 14C is about 8 kV, which is almost the same as the static focusing voltage Vfoc2 applied to the focusing electrodes 14D and 14E. The AC component Vd applied to the focusing electrodes 14D and 14E is 1 to 2 kV. In this case, the focusing electrodes 14B and 14C and the focusing electrodes 14D and 14E have slightly different potentials, but the difference is 2 kV or less, and both can be regarded as substantially the same potential. That is, the electrodes 14D, 14C, and 14B among the plurality of electrodes arranged on the beam generating unit side with respect to the anode-side focusing electrode 14E are applied with substantially the same voltage as the anode-side focusing electrode 14E, and the anode-side focusing electrode 14E. It is arranged continuously from. Accordingly, when a dynamic focus type electron gun is mounted, the position P1 in the present invention is defined by the position of the focusing electrode 14B on the beam generating side side in the tube axis direction. Therefore, the positions P0, PL1, PL2 and the distances L1, L2, L3 in the present invention when the dynamic focus type electron gun is mounted are the same as in FIG. 3 showing the case where the static focus type electron gun is mounted. This is as shown in FIG. Even in a color cathode ray tube equipped with a dynamic focus type electron gun, the same effect as in the first embodiment can be obtained if the following conditions are satisfied. That is, in the tube axis direction, the position P0 is located between the position PL1 and the position PL2. Further, L1> L2 and L1 <L3 are satisfied. Further, in the vertical direction, the range occupied by the conductive film 6 includes and is larger than the range occupied by the anode-side focusing electrode 14E.

  The distance L3 of the present invention will be further described. In the distance L3, a focus voltage is applied regardless of whether or not the alternating current component Vd that changes in synchronization with the deflection magnetic field is superimposed, and the distance L3 is continuously from the anode-side focusing electrode. It can also be defined as the length of the electrode group arranged in the tube axis direction.

(Embodiment 2)
In the second embodiment, a specific example of a color cathode ray tube according to the present invention will be described. The color cathode ray tube of the second embodiment is manufactured by a manufacturing method different from that of the first embodiment. Since the configuration of the color cathode ray tube is substantially the same as that of the first embodiment, only the manufacturing method will be described below.

  The exhaust process is performed in the same manner as in the manufacturing method of the first embodiment. Next, although the heating process for forming the conductive film is performed in the first embodiment, in this embodiment, the getter flash process is performed without performing the heating process.

  After the getter flash process is completed, a pressure resistance process is performed. However, in the pressure-resistant treatment process, when the pressure-resistant treatment between the anode-side focusing electrode 14E and the anode 15 is performed, the potential difference between these electrodes is greatly increased to generate sparks between the electrodes, and the thermal energy generated by the sparks. The anode-side focusing electrode 14E and / or the anode 15 are heated. Thereby, the conductive film 6 is formed by vapor-depositing substances constituting the anode-side focusing electrode 14E and / or the anode 15 on the inner wall of the neck portion 2B.

  After completing the pressure-resistant treatment process, a cathode activation process or the like is performed to complete the color cathode ray tube.

  When spark is generated between the anode-side focusing electrode 14E and the anode 15 in the pressure-resistant treatment process, only the surface layer portions of the areas facing the anode-side focusing electrode 14E and the anode 15 are partially heated. Changes in the position and shape of the focusing electrode 14E and the anode 15 are extremely difficult to occur.

(Embodiment 3)
In the third embodiment, a specific example of a color cathode ray tube according to the present invention will be described. The color cathode ray tube of the third embodiment is manufactured by a manufacturing method different from those of the first and second embodiments. Since the configuration of the color cathode ray tube is substantially the same as that of the first embodiment, only the manufacturing method will be described below.

  The color cathode ray tube according to the third embodiment is manufactured in the same manner as in Comparative Examples 1 and 2 except that the position for attaching the conductor (metal foil or metal ribbon) is different. That is, prior to the electron gun fixing step, a step of attaching a conductor on the anode-side focusing electrode 14E of the electron gun is performed, and in the heating step, the conductor is heated so that the constituent material of the conductor is removed from the neck portion 2B. A conductive film 6 separated from the internal conductive film 5 is formed by vapor deposition on the inner wall.

  The method for heating the conductor may be any known method. Preferably, the conductor is heated by high frequency heating using a coil. This is because the conductor can be efficiently heated to a temperature higher than that of the electrode such as the anode-side focusing electrode 14E. Moreover, it is because the surface of the conductor facing the neck portion 2B can be selectively heated.

  INDUSTRIAL APPLICABILITY The present invention can be used in a color cathode ray tube to suppress convergence drift of three electron beams and improve color purity in color display. The present invention can also be used to improve the image quality of color cathode ray tubes such as televisions and computer displays equipped with color cathode ray tubes.

FIG. 1 is a schematic cross-sectional view showing an example of the overall structure of a color cathode ray tube according to Embodiment 1 of the present invention. FIG. 2 is a schematic partial cut-away side view showing an example of the structure in the vicinity of the electron gun of the color cathode ray tube according to Embodiment 1 of the present invention. FIG. 3 is a schematic partial cut-away side view showing an example of the structure in the vicinity of the focusing electrode of the color cathode ray tube according to Embodiment 1 of the present invention. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a schematic cross-sectional view for explaining an example of a heating step in the method of manufacturing a color cathode ray tube according to Embodiment 1 of the present invention. FIG. 6 is a graph showing an example of the transition of the temperature (electrode temperature) of the anode-side focusing electrode with respect to the heating time in the heating step of the manufacturing method of the color cathode ray tube according to Embodiment 1 of the present invention. FIG. 7 is an explanatory diagram for explaining a process of attaching a metal ribbon (conductor) in the method of manufacturing a color cathode ray tube of Comparative Example 1. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 is an explanatory diagram for explaining a process of attaching a metal ribbon (conductor) in the method of manufacturing a color cathode ray tube of Comparative Example 2. FIG. 10 is a graph showing the relationship between the voltage application time and the convergence drift amount for the color cathode ray tubes of Examples and Comparative Examples 1 and 2. FIG. 11 is a graph showing the relationship between the voltage application time and the convergence drift amount for the color cathode ray tubes of the example and the comparative example 3. FIG. 12 is a schematic partially cut-away side view showing an example of the structure in the vicinity of the focusing electrode of the dynamic focus type electron gun of the color cathode ray tube according to Embodiment 1 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Panel 2 Funnel 2A Funnel part 2B Neck part 3 Phosphor screen 4 Electron gun 5 Internal conductive film 6,36 Conductive film 7 Shadow mask 10 Main lens 11 Cathode 12 Control electrode 13A, 13B Acceleration electrode 14A-14D Focusing electrode 14E Anode side Focusing electrode (focusing electrode)
DESCRIPTION OF SYMBOLS 15 Anode 16 Shield cup 17 Insulating holding member 18 Centering ring spring 19 Main lens facing area 20 Coil 21, 31 Conductor (metal ribbon, metal foil)
22A, 22B Rug

Claims (7)

An envelope having a funnel composed of a funnel portion and a neck portion, and a panel;
A phosphor screen provided on the inner wall of the panel;
An electron gun provided in an internal space of the neck portion and controlling generation of three electron beams arranged in an in-line direction, an electron gun including a plurality of focusing electrodes and an anode for controlling the focusing of the three electron beams;
A color cathode ray tube including an inner conductive film formed on a part of an inner wall of the funnel part and an inner wall of the neck part and electrically connected to the anode;
Further comprising a conductive film spaced from the internal conductive film on the inner wall of the neck portion,
Of the plurality of focusing electrodes, the position of the anode side focusing electrode located closest to the anode side in the tube axis direction at the anode side end is P0,
The tube at the end of the beam generator side of the electrode that is located closest to the beam generator among the electrodes that are applied with substantially the same voltage as the anode side focus electrode and are continuously arranged from the anode side focus electrode. The position in the axial direction is P1,
In the tube axis direction, when the position of the conductive film side end of the conductive film is PL1, and the position of the panel side end is PL2,
In the tube axis direction, the position P0 is located between the position PL1 and the position PL2,
The distance in the tube axis direction from the position P0 to the position PL1 is L1, the distance in the tube axis direction from the position P0 to the position PL2 is L2, and the distance in the tube axis direction from the position P0 to the position P1 is L3. When
L1> L2
L1 <L3
Satisfied,
A color cathode ray tube characterized in that the range occupied by the conductive film in the direction orthogonal to the tube axis and the in-line direction includes and is larger than the range occupied by the anode-side focusing electrode.   The color cathode ray tube according to claim 1, wherein the conductive film is a metal vapor deposition film.   The color cathode ray tube according to claim 1, wherein a gap between the anode-side focusing electrode and the anode is 1.0 mm or more. Forming a phosphor screen on the inner wall of the panel;
Forming an internal conductive film on the inner wall from the funnel part to a part of the neck part in the funnel;
Joining the panel and the funnel to form an envelope;
Fixing an electron gun including a beam generating unit, a plurality of focusing electrodes and an anode in the internal space of the neck portion;
A method of manufacturing a color cathode ray tube including an evacuation step of depressurizing and sealing the internal space of the envelope,
After the exhausting step, by heating the anode-side focusing electrode located closest to the anode among the plurality of focusing electrodes, the material constituting the anode-side focusing electrode is deposited on the inner wall of the neck portion, and A method of manufacturing a color cathode ray tube, further comprising a heating step of forming a conductive film separated from the internal conductive film.   5. The method of manufacturing a color cathode ray tube according to claim 4, wherein in the heating step, the heating is high-frequency heating using an external coil.   5. The method of manufacturing a color cathode ray tube according to claim 4, wherein in the heating step, a maximum temperature of the anode-side focusing electrode is in a range of 900 ° C. or higher and 1100 ° C. or lower.   In the heating step, a value obtained by integrating a differential temperature obtained by subtracting 900 ° C. from the temperature of the anode side focusing electrode over the entire time when the temperature of the anode side focusing electrode satisfies 900 ° C. or more is 0 ° C. · sec or more and 2500 ° C. -The manufacturing method of the color cathode ray tube of Claim 4 which is in the range below sec.

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