JP2005203284A - Electron gun and color picture tube device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a superior resolution over the whole picture without bringing about insulation destruction or the like among electrode pins even a dynamic focus voltage is made to be increased accompanied with increase of the maximum deflection amount of an electron beam. <P>SOLUTION: In an electron gun in which a first quadrupole lens L1 is formed that has a first and second convergence electrodes and a last accelerating electrode, and that has a convergence action in the horizontal direction among the first and second convergence electrodes and a diverging action in the vertical direction at no deflection time of the electron beam, while a dynamic focus voltage is superposed and applied to the second convergence electrode, the second convergence electrode and/or the last accelerating electrode are constituted so that components of the second quadrupole lens L2 is contained wherein a dynamic focus voltage of which fluctuation is smaller than that of the dynamic focus voltage applied the second convergence electrode is superposed and applied to the first convergence electrode, and so that the main lens Lm formed between the second convergence electrode and the last accelerating electrode offsets an action of the first quadrupole lens L1 at the no deflection time of the electron beam. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electron gun of a cathode ray tube used for a television receiver, a computer display, and the like, and a color picture tube apparatus including the electron gun.

  In general, a color picture tube apparatus has a panel and an envelope composed of a funnel integrally joined to the panel, and three electron beams emitted from an in-line type electron gun arranged in a neck portion of the funnel are received. A color screen is formed on the screen by raster scanning a phosphor screen which is deflected by horizontal and vertical deflection magnetic fields generated by a deflection device mounted on the outside of the funnel and thereby faces the shadow mask on the inner surface of the panel. It is configured to display an image.

  Usually, a main lens electric field is formed between the focusing electrode and the final accelerating electrode arranged at the subsequent stage of the electron gun, thereby converging the three RGB electron beams on the corresponding pixels on the phosphor screen. However, even if the focusing power of the main lens electric field is set so that the three electron beams are concentrated at one point in the central portion of the phosphor screen surface, as the amount of deflection of the electron beam increases, the fluorescence Since the trajectory of the electron beam to reach the body screen becomes longer, the three electron beams are over-concentrated on the screen at the periphery of the screen.

Therefore, in particular, in a color cathode ray tube using an in-line type electron gun, in order to obtain a self-convergence effect, the horizontal deflection magnetic field is distorted in a pin cushion shape and the vertical deflection magnetic field is distorted in a barrel shape.
Therefore, each electron beam passing through the deflection magnetic field has a diverging action in the horizontal deflection direction (hereinafter simply referred to as “horizontal direction”) and a focusing action in the vertical deflection direction (hereinafter simply referred to as “vertical direction”). receive. The influence of the distortion of the deflection magnetic field in this self-convergence method is particularly noticeable in the peripheral portion of the phosphor screen surface, and each electron beam spot on the phosphor screen (hereinafter simply referred to as “beam spot”). As a result, there is an inconvenience that the focus becomes blurred due to overfocusing at the periphery of the screen and the resolution deteriorates.

  In order to solve such a problem, Patent Document 1 discloses that a final acceleration voltage is applied to each electron beam in the electron gun by gradually increasing the focus voltage applied to the focusing electrode as the amount of deflection of the electron beam increases. By reducing the potential difference between the main lens field and the main lens field, the focusing action of the main lens field is weakened, forming a so-called quadrupole lens field that has a focusing function in the horizontal direction and a diverging action in the vertical direction. Discloses a configuration in which an electron beam is transformed into a vertically long elliptical shape and then emitted into a deflection magnetic field.

As a result, the beam spot on the phosphor screen can be optimized by canceling the horizontal and vertical deformations even when the horizontal diverging action and the vertical focusing action are caused by the deflection magnetic field distortion as described above. Is possible.
FIG. 27 is a plan view showing the electrode configuration of the electron gun 100 in the picture tube device described in Patent Document 1 above, parallel to the in-line arrangement direction (horizontal direction) of the cathode and passing through the center of each electron beam passage hole. (Hereinafter, in this specification, a cross-sectional view of the electrode configuration in such a plane is simply referred to as a “cross-sectional view showing the electrode configuration”).

For simplification of the drawing, the shield cup and the cathode are not shown in the cross section (the same applies hereinafter).
As shown in the figure, the electron gun 100 includes three cathodes 111 to 113 arranged in-line in the horizontal direction, a control electrode 114, an acceleration electrode 115, a first focusing electrode 116, a second focusing electrode 117, and a final acceleration electrode. 118 and a shield cup 119.

  In this electron gun 100, the focusing electrode is composed of first and second cylindrical first and second focusing electrodes 116 and 117, and the first focusing electrode 116 is shown on the end surface of the second focusing electrode side. As shown in FIG. 28 (a), vertically long electron beam passage holes 116a to 116c are formed, and a laterally long electron beam passage hole as shown in FIG. 28 (b) is formed on the end surface of the second focusing electrode 117 on the first focusing electrode 116 side. 117a to 117c are formed, and focus voltages Vfoc1 and Vfoc2 as shown in FIG. 29 are applied to the first and second focusing electrodes 116 and 117, respectively.

FIG. 29 is a diagram showing the relationship between the amount of deflection of the electron beam and each focus voltage when the electron beam is deflected in the horizontal direction. The horizontal axis represents the deflection position of the electron beam, and the vertical axis represents the change in each focus voltage. Show.
Here, the focus voltage Vfoc1 is constant at the potential Vh, and the focus voltage Vfoc2 is overlapped with the parabolic dynamic focus voltage Vdyn that gradually increases in accordance with the deflection amount of the electron beam.

FIG. 30 is a schematic diagram showing a lens electric field (hereinafter, simply referred to as “lens”) generated by such an electrode configuration, where the upper half is the lens action in the horizontal direction and the lower half is vertical. The lens action in each direction is shown.
First, at the center of the screen, as shown in FIG. 29, both the focus voltages Vfoc1 and Vfoc2 have the potential Vh, and since there is no potential difference, no lens electric field is generated between the first and second focusing electrodes 116 and 117. A main lens electric field La is generated between the two focusing electrodes 117 and the final acceleration electrode 118 (see FIG. 30A).

However, as the amount of deflection of the electron beam increases and the irradiation position moves to the periphery of the phosphor screen, the dynamic focus voltage Vdyn is superimposed and the focusing voltage Vfoc2 rises (FIG. 29), and the focusing voltage Vfoc1. , Vfoc2 has a potential difference, so that a lens is generated between the first and second focusing electrodes 116 and 117. At this time, electron beam passage holes on the opposing surfaces of the focusing electrodes are formed as shown in FIGS. Thus, an axially asymmetric quadrupole lens having a focusing action in the horizontal direction and a diverging action in the vertical direction is formed between the electrodes as indicated by Lb in FIG. 30B. It is possible to cancel the deformation force acting on the electron beam due to the distortion of the deflection magnetic field and finally obtain an optimum beam spot on the phosphor screen.
JP-A-61-99249

  Today, however, the screen size of the picture tube device is increasing and the depth size is decreasing. As a result, the maximum deflection angle of the electron beam is increasing, and the front panel is flattened. Thus, the dynamic focus voltage Vdyn applied when the electron beam is deflected to the peripheral portion of the screen has become very high as Vfoc2 ′ shown by the broken line in FIG.

  On the other hand, in order to supply a voltage to each cathode and electrode of the electron gun from the outside, a plurality of electrode pins are provided upright on the end face of the neck portion 105 of the cathode ray tube. FIG. 31 is a diagram showing an example thereof. As shown in FIG. 31, the electrodes for the first and second focusing electrodes are arranged in the circumferential direction of the disk-shaped glass material 106 sealed at the end of the neck portion 105. The pins 1061 and 1062 and other electrode pins 1063 for applying a voltage to the other cathode, control electrode, and acceleration electrode are provided upright. The interval and arrangement between these electrode pins are defined and cannot be easily changed.

However, as described above, when the dynamic voltage superimposed on the second focusing electrode 117 at the periphery of the screen becomes higher as indicated by the broken line Vfoc2 ′ (FIG. 29), the potential difference Δv1 with the first focusing electrode 116 at that time is 2 kV. There is a risk of exceeding.
Each electrode pin is insulated by glass, but since the distance between the electrode pin 1061 for the first focusing electrode and the electrode pin 1062 for the second focusing electrode is relatively close, the potential difference between the two electrodes is 2 kV. Exceeding this causes dielectric breakdown and causes image defects.

  The present invention has been made in view of the above problems, and even when the potential of the dynamic voltage applied when the electron beam is deflected to the peripheral part by increasing the maximum deflection angle or the like needs to be increased, It is an object of the present invention to provide an electron gun configured so as not to cause an image defect due to dielectric breakdown between electrode pins and a color picture tube apparatus using the electron gun.

 In order to achieve the above object, an electron gun according to the present invention is housed in a neck portion of a cathode ray tube and includes a plurality of cathodes arranged in-line in a first direction orthogonal to the tube axis of the cathode ray tube, Focusing electrode, a second focusing electrode, and a main lens forming portion, and has a focusing action in the first direction by the first and second focusing electrodes when the electron beam is not deflected. In addition, a first quadrupole lens electric field having a diverging action is formed in a second direction orthogonal to the tube axis, and a focus voltage that gradually increases as the amount of deflection of the electron beam increases is applied to the second focusing electrode. In this electron gun, a voltage having a potential lower than the focus voltage applied to the second focusing electrode and having a smaller potential increase rate than the focus voltage is applied to the first focusing electrode. The main len The forming unit has a plurality of cylindrical electrodes to which a higher voltage is applied in the subsequent stage of the traveling direction of the electron beam, and at least a pair of cylindrical electrodes adjacent to each other among the plurality of cylindrical electrodes has a low level. A second quadrupole lens electric field in which the focusing action in the first direction is weaker than the focusing action in the second direction according to the potential difference between the potential side electrode and the high potential side electrode is at least when the electron beam is not deflected. It is comprised so that it may form.

Further, the present invention is characterized in that, when the electron beam is not deflected, a focusing force obtained by combining the first and second quadrupole lens electric fields is substantially equal in the first and second directions.
Furthermore, the present invention is characterized in that a potential difference between voltages applied to the first and second focusing electrodes is approximately 2 kV or less during maximum deflection of the electron beam.
Furthermore, in the present invention, the shape of the cross section of the cylindrical electrode on the low potential side is relatively second than the shape of the cross section of the cylindrical electrode on the high potential side. It is characterized by flattening in the direction of.

  Furthermore, in the present invention, a plate-like correction electrode in which a plurality of electron beam passage holes through which the plurality of electron beams pass is formed in each of the adjacent pair of cylindrical electrodes. At least one of the plurality of electron beam passage holes of the correction electrode of the cylindrical electrode on the low potential side is disposed at a position retreated from the opposing end surfaces of the pair of cylindrical electrodes, and the inner diameter in the second direction is The ratio of the inner diameter in the first direction is set to be larger than the ratio in the electron beam passage hole corresponding to the correction electrode of the cylindrical electrode on the high potential side.

  Further, according to the present invention, for the at least one pair of adjacent cylindrical electrodes, the plurality of electron beams are respectively provided inside the first cylindrical electrode on the low potential side and the second cylindrical electrode on the high potential side. A plate-like correction electrode in which a plurality of electron beam passage apertures are formed is disposed at a position retracted by a first distance and a second distance from opposite end faces of the pair of cylindrical electrodes, respectively. The first distance is set to be larger than the second distance.

  Furthermore, the present invention provides a plate-like correction electrode in which a plurality of electron beam passage holes through which the plurality of electron beams pass are formed in each of the adjacent pair of cylindrical electrodes. It is disposed at a position retracted from the opposite end face of the cylindrical electrode, and the correction electrode of the low potential side cylindrical electrode has a screen-like shape erected so as to sandwich the plurality of electron beam passage holes from above and below. An electrode is provided.

Here, the present invention is characterized in that the second focusing electrode also serves as the cylindrical electrode on the low potential side.
An electron gun according to the present invention is housed in a neck portion of a cathode ray tube and is arranged in-line in a first direction orthogonal to the tube axis of the cathode ray tube, a first focusing electrode, 2 focusing electrodes and a main lens forming portion, and when the potential of the first focusing electrode is higher than the potential of the second focusing electrode, the first and second focusing electrodes diverge in the first direction. And a first quadrupole lens electric field having a focusing action in the first direction and a second direction orthogonal to the tube axis is formed, and the amount of deflection of the electron beam is increased on the second focusing electrode. An electron gun to which a gradually increasing focus voltage is applied, and the rate of increase in potential of the first focusing electrode is smaller than that of the focus voltage applied to the second focusing electrode, and at least the electron beam Focus when no deflection A voltage having a potential higher than the pressure is applied, and the main lens electric field formed by the main lens forming unit is configured such that the focusing action in the first direction is stronger than the focusing action in the second direction. It is characterized by being.

  Here, in the present invention, the main lens forming portion is formed by arranging the first, second, and third cylindrical electrodes in this order along the traveling direction of the electron beam. A second quadrupole lens electric field is formed between which the focusing action in the second direction is stronger than the focusing action in the first direction, and the focusing in the first direction is between the second and third cylindrical electrodes. A third quadrupole lens electric field whose action is stronger than the focusing action in the second direction is formed, and when the second and third quadrupole lens electric fields are combined, the focusing action in the first direction is the second It is characterized by being configured to be stronger than the focusing action in the direction.

Furthermore, the present invention is characterized in that the second focusing electrode also serves as the first cylindrical electrode in the main lens forming portion.
Further, according to the present invention, the first focusing electrode is connected to the electrode to which the highest potential is applied in the electron gun via the first resistor, and is connected to the ground electrode pin via the second resistor. Thus, the voltage of the highest potential is resistance-divided and a predetermined voltage is applied to the first focusing electrode.

  In addition, a color picture tube apparatus according to the present invention includes a cathode ray tube having an electron gun housed in a neck portion, and a deflection apparatus for deflecting an electron beam emitted from the electron gun in horizontal and vertical directions. In this case, the electron gun is used as the electron gun, and a first focusing voltage whose potential gradually increases with an increase in the deflection amount of the electron beam is applied to the second focusing electrode of the electron gun. Voltage supply means, and second voltage supply means for supplying a voltage that changes following the focus voltage to the first focusing electrode at a rate of increase smaller than the rate of increase of the focus voltage. It is characterized by.

  Here, in the present invention, the first and second voltage supply means include a first quadrupole lens electric field formed between the first and second focusing electrodes when the electron beam is not deflected, and a main Supplying voltages to the first and second focusing electrodes so that the magnitudes of the focusing effects in the first and second directions are substantially equal when the main lens electric field formed by the lens unit is combined. It is characterized by.

  Further, in the present invention, in the electron gun, the first focusing electrode is connected to the electrode to which the highest potential is applied in the electron gun via the first resistor, and the first electrode is connected to the ground electrode pin and the first electrode. And the second voltage supply means is configured to apply a predetermined voltage to the first focusing electrode by dividing the voltage of the highest potential by resistance. It is a voltage distribution circuit composed of the first and second resistors.

  According to the electron gun of the present invention, the first focusing electrode is applied with a voltage having a lower potential than the focus voltage applied to the second focusing electrode and a smaller potential increase rate than the focus voltage. Therefore, the potential difference between the first and second focusing electrodes at the time of maximum deflection of the electron beam can be made smaller than in the conventional case, and dielectric breakdown occurs between the electrode pins for supplying power to them. Such a thing disappears.

  Further, the main lens forming unit has a configuration in which at least a pair of adjacent cylindrical electrodes are focused in the first direction according to the potential difference between the low potential side electrode and the high potential side electrode when the electron beam is not deflected. Since the second quadrupole lens electric field whose action is weaker than the focusing action in the second direction is generated, for example, the low-potential side cylindrical electrode is also used as the second focusing electrode. As a result, as the focus voltage rises due to the dynamic voltage applied in an overlapping manner, the potential difference from the cylindrical electrode on the high potential side is reduced, and the second quadrupole lens action is weakened. On the other hand, the potential difference between the first and second focusing electrodes increases as the focus voltage increases, and the action of the first quadrupole lens increases. Since the second quadrupole lens is configured to cancel the first quadrupole lens action at least when the electron beam is not deflected, the first quadrupole lens action increases and the second quadrupole lens action decreases in this way. By doing so, the increase rate of the first quadrupole lens action for correcting the deformation of the beam spot of the electron beam due to the distortion of the deflection magnetic field can be substantially improved.

As a result, an optimum focus state can be obtained even at the periphery of the screen, and the resolution of the entire screen of the color picture tube device can be improved.
Further, according to the electron gun of the present invention, since the voltage having a smaller potential increase rate than the focus voltage applied to the second focusing electrode is applied to the first focusing electrode, the maximum deflection of the electron beam At this time, the potential difference between the first and second focusing electrodes can be made smaller than in the conventional case, and dielectric breakdown does not occur between the electrode pins for supplying power to them.

  In the case where the main lens electric field formed by the main lens forming unit is configured such that the focusing action in the first direction is stronger than the focusing action in the second direction, at least the electron beam is not deflected. Sometimes, by making the potential of the first focusing electrode higher than the potential of the second focusing electrode, a quadrupole lens component that cancels the quadrupole lens action of the main lens occurs between the first and second focusing electrodes. As the focus voltage increases, the potential difference between the first and second focusing electrodes decreases, and the quadrupole lens component formed between them decreases, resulting in a beam spot of the electron beam due to deflection magnetic field distortion. The action of the quadrupole lens for correcting the deformation is increased. Here, in particular, if the potential of the second focusing electrode becomes higher than the potential of the first focusing electrode as the amount of deflection of the electron beam increases, the beam between the first and second focusing electrodes is also increased. A quadrupole lens action for correcting the deformation of the spot is generated, and when combined with the quadrupole lens action of the main lens part, it is possible to obtain an optimum focus state at the periphery of the screen, and the entire screen of the color picture tube device The resolution can be improved.

  Further, according to the color picture tube apparatus of the present invention, the above-mentioned electron gun is used, and a focus voltage in which the potential gradually increases as the amount of deflection of the electron beam increases is supplied to the second focusing electrode of the electron gun. And a second voltage supply means for supplying, to the first focusing electrode, a voltage that changes following the focus voltage at an increase rate smaller than the increase rate of the focus voltage. Thus, an optimum focus state can be obtained even at the periphery of the screen, and the resolution of the entire screen of the picture tube device can be improved.

Hereinafter, a color picture tube apparatus according to an embodiment of the present invention will be described with reference to the drawings.
<First Embodiment>
(Overall configuration of color picture tube device)
FIG. 1 is a partially cutaway cross-sectional view showing an outline of the configuration of a color picture tube apparatus 1 according to the present embodiment.

As shown in the figure, a color picture tube apparatus 1 according to the present invention has an envelope made up of a panel 2 and a funnel 3, and blue, green and red phosphors are coated on the inner surface of the panel 2. The phosphor screen 4 thus formed is formed.
An inline electron gun 6 is housed in the neck portion 5 of the funnel 3 facing the phosphor screen 4. Also, the horizontal deflection coil and the vertical deflection coil, which are emitted from the electron gun 6 in response to the input signal and are provided along the boundary surface between the neck portion 5 and the funnel 3, corresponding to the phosphors of the respective colors. The deflecting device 9 is configured to pass through a deflection magnetic field and be deflected by a predetermined amount in the vertical and horizontal directions, and reach the phosphor screen 4 through the aperture formed in the shadow mask 8. The The deflection device 9 is supplied with a horizontal deflection current and a vertical deflection current synchronized with the horizontal synchronization signal and the vertical synchronization signal from a deflection circuit (not shown).

(Configuration of electron gun)
Hereinafter, the configuration of the electron gun 6 provided in the color picture tube apparatus 1 will be described in detail.
2 is a partially cutaway perspective view of the electron gun 6 according to the first embodiment, and FIG. 3 is a longitudinal sectional view showing an electrode configuration of the electron gun 6 of FIG.
As shown in these drawings, the electron gun 6 includes three cathodes 11, 12, 13 (see FIG. 3) arranged in-line, a control electrode 14 that accommodates them inside, an acceleration electrode 15, The first focusing electrode 16, the second focusing electrode 17, the final acceleration electrode 18, and the shield cup 19 are sequentially arranged. These electrodes are supported by an insulating support frame (not shown) so that their positional relationship does not shift.

The control electrode 14, the first and second focusing electrodes 16, 17, and the final electrode 18 are each a flat cylindrical electrode that is long in the horizontal direction and surrounds three electron beams, and is on the acceleration electrode 15 side of the control electrode 14. Three substantially circular electron beam passage holes are provided on the surface, the acceleration electrode 15, and the surface of the first focusing electrode 16 on the acceleration electrode 15 side, corresponding to the RGB electron beams.
Further, on the opposing surfaces 161 and 171 of the first focusing electrode 16 and the second focusing electrode 17, as shown in FIGS. 5 (a) and 5 (b), vertically long electron beam passage holes 16a to 16c and horizontally long electron beams are provided. When the through holes 17a to 17c are formed and a potential difference is generated between the first focusing electrode 16 and the second focusing electrode 17, a quadrupole lens is formed between the electrodes.

Further, as shown in FIG. 3, three electron beam passage holes 20a to 20c and 21a to 21a are located inside the second focusing electrode 17 and the final accelerating electrode 18 at positions retracted by a predetermined amount from the opposing end faces of both electrodes. The correction electrodes 20 and 21 having 21c are arranged so as to be orthogonal to the longitudinal direction of the electron gun 61 (the traveling direction of the electron beam).
By providing such correction electrodes 20 and 21, the main lens formed by the second focusing electrode 17 and the final acceleration electrode 18 is a so-called over wrapping field (hereinafter abbreviated as “OLF”). It is formed as a lens (hereinafter, an electron gun having an OLF lens is referred to as an “OLF lens type electron gun”).

Since this OLF lens is known from, for example, Japanese Patent Publication No. 2-18540, the principle will be briefly described here.
In general, it is known that a lens formed in an electron gun has a smaller spherical aberration and a smaller spot diameter as the aperture is larger, and thus further improvement in resolution can be expected. However, there is a limit to increasing the diameter of the neck portion of the cathode ray tube, and the interval between the RGB electron beams cannot be increased beyond a certain level in the electron gun housed therein. By overlapping a part of the corresponding three separated lenses, the diameter of the three separated lenses can be increased.

  The correction electrodes 20 and 21 play a role of generating three main lenses separated corresponding to each of the three electron beams, and the second focusing electrode 17 and the final acceleration electrode 18 forming the main lens are used. By disposing the correction electrodes 20 and 21 inwardly on the cylindrical outer peripheral electrodes 172 and 182 respectively, a low potential is deeply penetrated into the second focusing electrode 17 and the final acceleration electrode A high potential is caused to penetrate deeply into the interior 18. As a result, the lens diameter of each separated main lens is effectively enlarged, whereby the spot diameter on the phosphor screen can be further reduced, which greatly contributes to the improvement of the resolution.

As shown in FIG. 3, a predetermined control voltage Vc, acceleration voltage Vb, first focus voltage Vfoc1, and second control electrode 14, acceleration electrode 15, first focusing electrode 16, and second focusing electrode 17 are provided on the electrodes. A focus voltage Vfoc2 is applied, and an anode voltage Va is applied to the final acceleration electrode 18 via a shield cup 19.
The first focus voltage Vfoc1 applied to the first focusing electrode 16 is obtained by convolution of the dynamic focus voltage Vdyn1 with the reference voltage V1, and the second focus voltage Vfoc2 applied to the second focusing electrode 17 is the reference voltage V2. And the dynamic focus voltage Vdyn2 is overlapped.

  As shown in FIG. 4, the reference voltage V2 is set higher by Δv3 than V1, and the rate of increase of the dynamic focus voltage Vdyn1 is smaller than the rate of increase of the dynamic focus voltage Vdyn2, and Vfoc2 and Vfoc1 in the peripheral portion The potential difference ΔV2 is set to be smaller than the withstand voltage (usually 2 kV) between the electrode pins 1061 and 1062.

  As described above, since the first focus voltage Vfoc1 increases as the second focus voltage Vfoc2 increases, the peripheral portion of the screen is scanned even if the dynamic focus voltage Vdyn2 increases due to the increase in the maximum deflection angle. At this time, the potential difference Δv2 between the first and second focusing electrodes 16 and 17 can be kept below the withstand voltage between the corresponding electrode pins, and dielectric breakdown between the electrode pins 1061 and 1062 does not occur.

  However, with such a configuration, even if the amount of deflection of the electron beam increases, the potential difference between the first and second focusing electrodes 16 and 17 does not increase so much. The lens action of the power field of the power quadrupole lens becomes weak, so that the deformation of the beam spot due to the distortion of the deflection magnetic field cannot be sufficiently corrected, resulting in a disadvantage that a good beam spot shape cannot be obtained.

Therefore, in the present embodiment, in order to compensate for the deterioration of the lens action of the quadrupole lens formed between the first and second focusing electrodes 16 and 17, the second focusing electrode 17. The main lens formed between the final acceleration electrodes 18 also has a quadrupole lens action.
Specifically, as shown in FIGS. 6A and 6B, the electron beam passage holes 20 a to 20 c of the correction electrode 20 on the low potential side are more than the shapes of the electron beam passage holes 21 a to 21 c of the correction electrode 21. By adopting a relatively horizontally long shape, the focusing force in the horizontal direction of the main lens formed between the two electrodes is configured to be a predetermined amount weaker than the focusing force in the vertical direction.

(Lens action)
FIGS. 7A and 7B are schematic views showing the contents of the lens action of the quadrupole lens and the main lens formed in the electron gun in the present embodiment. FIG. 7A shows the contents of the lens action that occurs when the electron beam is in the center of the screen (no deflection), and FIG. 7B shows the lens action that occurs when the electron beam is deflected to the periphery on the horizontal axis. The upper side of the horizontal line at the center shows the lens in the horizontal direction, and the lower side shows the lens in the vertical direction.

Here, the main lens Lm actually acts as a common lens for three electron beams, but in the figure, it is shown as being for one electron beam for convenience.
In addition, as described above, by relatively changing the shapes of the cylindrical electrodes of the second focusing electrode 17 and the final acceleration electrode 18, the main lens Lm has a focusing force in the horizontal direction that is weaker than that in the vertical direction. Therefore, an axially symmetric lens (hereinafter referred to as “axially symmetric lens”) L3 having the same focusing force in the horizontal and vertical directions, and an axis having a diverging action in the horizontal direction and a focusing action in the vertical direction. It can be understood as a combination of asymmetric quadrupole lenses L2.

First, as shown in FIG. 4 when the electron beam is not deflected, the potential of the second focusing electrode 17 is higher than the first focusing electrode 16 by Δv3, so that the quadrupole lens L1 is generated in this portion.
A main lens Lm composed of a quadrupole lens L2 and an axially symmetric lens L3 is formed between the second focusing electrode 17 and the final acceleration electrode 18. Hereinafter, in order to distinguish between the two quadrupole lenses L1 and L2, the former quadrupole lens is referred to as a “first quadrupole lens” and the latter quadrupole lens is referred to as a “second quadrupole lens”.

As shown in FIG. 7A, when the electron beam is not deflected, the focusing and divergence of the lens action in the horizontal and vertical directions of the first and second quadrupole lenses are reversed.
The focusing force of the first quadrupole lens L1 in the horizontal direction and the diverging force of the second quadrupole lens L2 and the diverging force of the first quadrupole lens L1 in the vertical direction and the focusing force of the second quadrupole lens L2 are: The conditions are set so that they are canceled each other (hereinafter simply referred to as “the quadrupole lens action is canceled”).

  Specifically, (b) the magnitude of the potential difference Δv3 between the reference potentials V1 and V2 of the two focusing electrodes, and (b) the electron beam passage hole formed on the opposing surfaces of the first focusing electrode 16 and the second focusing electrode 17. And (c) the shape of the electron beam passage hole in the correction electrodes 20 and 21, etc., by adjusting at least one condition, the lens action of the quadrupole lenses L1 and L2 when the electron beam is not deflected is adjusted. Offsetting is possible.

  As the deflection angle of the electron beam increases, the potentials of the first focusing electrode 16 and the second focusing electrode 17 rise while widening the potential difference (see FIG. 4), and the electron beam is deflected to the periphery. Then, since the potential difference between the first focusing voltage Vfoc1 and the second focusing voltage Vfoc2 is larger than that during no deflection, the focusing and diverging actions of the first quadrupole lens L1 in the horizontal and vertical directions become stronger. Since the potential difference is not as great as in the prior art, the lens action of the first quadrupole lens L1 is not so strong as to completely complement the deformation of the beam spot due to the distortion of the deflection magnetic field.

  However, as the potential of the second focusing electrode 17 increases, the potential difference from the final acceleration electrode 18 becomes smaller and the quadrupole lens action of the second quadrupole lens L2 becomes weaker. Since the first quadrupole lens L1 has a potential difference Δv3 between the first and second focusing electrodes 16 and 17 even when it is not deflected, a quadrupole lens action of a predetermined size originally occurs, and the electron beam As the amount of deflection increases, the lens action of the first quadrupole lens L1 further increases, while the lens action of the second quadrupole lens L2 that has the effect of canceling out the lens action decreases. Together, the magnitude of the action of the quadrupole lens obtained by combining the first and second quadrupole lenses L1 and L2 is substantially the same as when the potential of the first focusing electrode 16 is not increased (see FIG. 29). You can get things.

  Accordingly, the first quadrupole lens L1 and the first quadrupole lens L1 and the first focusing electrode 16 are overlapped with the first focusing electrode 16 while preventing dielectric breakdown between the electrode pins corresponding to the first and second focusing electrodes by folding the dynamic focusing voltage Vdyn1. By combining the two lenses L2 and L3 of the main lens Lm, it is possible to maintain an optimal focus state in the horizontal direction and the vertical direction, so that it is possible to optimize the beam spot shape and obtain a high resolution over the entire screen screen. Become.

(Dynamic focus voltage circuit)
According to the present embodiment, the first and second dynamic focus voltage circuits for applying the dynamic focus voltage to the first focusing electrode 16 and the second focusing electrode 17 are necessary. The dynamic focus voltage circuit can be used to make the reference voltage (V1, V2) different from the rate of increase of the dynamic focus voltage superimposed on the reference voltage (V1, V2).

FIG. 8 is a block diagram showing a configuration example of the dynamic focus voltage circuit 200. As shown in FIG.
As shown in the figure, the dynamic focus voltage circuit 200 includes a horizontal parabola voltage generation circuit 201, a vertical parabola voltage generation circuit 202, an adder 203, a resistor 204, a resistor 205, a high voltage generation circuit 206, and the like.

  The horizontal parabolic voltage generation circuit 201 receives a horizontal synchronization signal and generates a horizontal parabolic voltage whose voltage waveform changes in a parabolic shape every horizontal deflection period. The vertical parabola voltage generation circuit 202 receives a vertical synchronization signal and generates a vertical parabola voltage whose voltage waveform changes in a parabolic shape every vertical deflection period. The adder 203 synthesizes both parabolic voltages and convolves the voltage V2 output from the high voltage generation circuit 206 with the second dynamic focus voltage Vdyn2, thereby generating a focus voltage Vfoc2.

The first dynamic focus voltage Vdyn1 is generated by dividing the second dynamic focus voltage Vdyn2 by resistors 204 and 205, and is convolved with the voltage V1 output from the high voltage generation circuit 206 to be the first focus voltage. Vfoc1.
The high voltage generation circuit 206 is mainly composed of a flyback transformer, and outputs a high voltage anode voltage Va and reference voltages V1 and V2.

(Modification in the first embodiment)
Next, in the OLF lens type electron gun according to the first embodiment, in addition to changing the shape of the electron beam passage holes of the correction electrodes 20 and 21 as shown in FIG. A modification for providing a lens action will be described.
(Modification 1)
In the electron gun according to the first modification, the second quadrupole lens action is provided by adjusting the position where the correction electrode is provided.

Specifically, as shown in the electron gun 61 of FIG. 9, the retraction distance of the correction electrode 20 from the end face 173 of the second focusing electrode 17 is L1, and the retraction distance of the correction electrode 21 from the end face 183 of the final acceleration electrode 18 is. Is set to L2, and L1> L2 is set to provide the second quadrupole lens action.
In other words, the OLF lens is regarded as a combined lens of individual lenses formed by electron beam passage holes of a pair of opposing correction electrodes 20 and 21 and a common lens generated by a pair of opposing outer peripheral electrodes 172 and 182. As described above, the correction electrode 20 on the low potential side recedes more than the correction electrode 21 on the high potential side, so that the electric field due to the laterally long opening of the outer peripheral electrode 172 penetrates deeper into the lower voltage side, and the correction electrode 20 Since it becomes stronger than the electric field, the focusing force in the horizontal direction becomes weaker than the focusing force in the vertical direction, and a second quadrupole lens component is created.

(Modification 2)
This modification 2 is characterized in that a second quadrupole lens action is provided by providing the correction electrode 20 with a screen-type electrode extending in the horizontal direction.
FIG. 10 is a partial longitudinal sectional view showing the main part of the electrode configuration of the electron gun 62 according to the second modification. As shown in the figure, a partition type electrode 27 is formed on the first focusing electrode 16 side of the correction electrode 20 of the second focusing electrode 17.

As shown in the perspective view of FIG. 11, the screen-type electrode 27 is erected so as to sandwich each electron beam passage hole of the correction electrode 20 from the vertical direction, and extends in an eave shape in the traveling direction of the electron beam. It consists of electrode plates 27a and 27b.
In this way, the pair of electrode plates 27a and 27b to which the low potential is applied and extend in the traveling direction of the electron beam apply a focusing action to each electron beam in the vertical direction. Therefore, the main lens can have the above-described second quadrupole lens action.

In the above description, the partition electrode 27 is provided on the first focusing electrode 16 side of the correction electrode 20, but may be provided on the final acceleration electrode 18 side of the correction electrode 20.
(Modification 3)
In the third modification, the shape of the cylindrical outer peripheral electrode 172 of the second focusing electrode 17 and the cylindrical outer peripheral electrode 182 of the final accelerating electrode 18 are relatively changed, whereby the second quadrupole lens acts on the main lens. There is a feature in that it is made to have.

12 (a) and 12 (b) show shapes when the cylindrical outer peripheral electrode 172 of the second focusing electrode 17 and the cylindrical outer peripheral electrode 182 of the final acceleration electrode 18 are viewed from the tube axis direction of the neck portion, respectively. FIG.
As shown in the figure, in this modification, the vertical diameter R2 of the outer peripheral electrode 182 of the final acceleration electrode 18 is made larger than the vertical diameter R1 of the outer peripheral electrode 172 of the second focusing electrode 17. Yes. In other words, the cross-sectional shape of the outer peripheral electrode 172 of the second focusing electrode 17 is formed so as to be relatively longer than the cross-section of the outer peripheral electrode 182 of the final accelerating electrode 18, thereby forming between the two electrodes. The focusing force in the horizontal direction of the main lens is configured to be a predetermined amount weaker than the focusing force in the vertical direction.

<Second Embodiment>
The configuration of the color picture tube apparatus body according to the second embodiment is the same as that of the first embodiment, and the electrode configuration of the electron gun 6, particularly the configuration in which the main lens has a second quadrupole lens action. Therefore, only the characteristic electrode configuration will be described (hereinafter, the same applies to other embodiments).

  In the first embodiment described above, in the OLF lens type electron gun, the configuration in which the OLF lens has the second quadrupole lens action has been described. In the second embodiment, the second focusing electrode is used. A cylindrical intermediate electrode is disposed between the first acceleration electrode 18 and the final acceleration electrode 18 to further increase the diameter of each individual main lens (hereinafter, this lens is referred to as an “EX-OLF lens”). A second quadrupole lens action is provided between the focusing electrodes 17.

FIG. 13 is a longitudinal sectional view showing the configuration of the electron gun 63 according to the second embodiment.
As shown in the figure, the electron gun 63 is different from the OLF lens type electron gun 6 shown in FIG. 3 in that a cylindrical intermediate electrode 24 is provided between the fourth focusing electrode 17 and the final acceleration electrode 18. Is different.
Similar to the second focusing electrode 17 and the final acceleration electrode 18, the intermediate electrode 24 is a plate-shaped correction electrode 25 having three noncircular electron beam passage holes inside a cylindrical electrode having a flat cross section. Is provided.

A voltage Vm is applied to the intermediate electrode 24, and this voltage Vm is higher than the focus voltage Vfoc2 applied to the second focusing electrode 17 and lower than the anode voltage Va applied to the final acceleration electrode 18. An appropriate voltage of about 10 to 17 kV is applied.
As described above, in the electron gun 63 according to the second embodiment, the main lens formed by the three electrodes of the second focusing electrode 17, the intermediate electrode 24, and the final acceleration electrode 18 is expanded in the tube axis direction. Therefore, the effective lens aperture of the individual lens electric fields separated thereby can be made larger than that of the OLF lens according to the second embodiment.

Note that the formation principle of the EX-OLF lens is detailed in Japanese Patent Laid-Open No. 9-180648, and further description thereof is omitted.
In the present embodiment, in the EX-OLF lens type electron gun 63 provided with such an intermediate electrode, the backward distance (L1) of the first focusing electrode 16 from the end of the correction electrode 20 on the intermediate electrode side is set. The intermediate electrode 24 is set to be larger than the receding distance (Lm) from the end of the correction electrode 25 on the first focusing electrode 16 side (L1> Lm).

As a result, like the electron gun 6 according to the first embodiment, the horizontal focusing action of the main lens can be made smaller than the vertical focusing action.
In the electron gun 63 according to the present embodiment, the main lens is configured by the three electrodes of the second focusing electrode 17, the intermediate electrode 24, and the final acceleration electrode 18, but the intermediate electrode is further increased in order to increase the lens diameter. The main lens may be configured by four or more electrodes. In this case, the structure which produces the said 2nd quadrupole lens effect | action between at least a pair of electrodes adjacent among those electrodes should just be included.

In this embodiment, the principle of the first modification of the first embodiment is used to give the main lens the second quadrupole lens action. However, the first embodiment The second quadrupole lens action may be created by adopting the other configuration described in the above.
<Third Embodiment>
The third embodiment is characterized in that the focus voltage Vfoc1 applied to the first focusing electrode 16 is obtained from the anode voltage Va by resistance division. By doing so, it is not necessary to supply the focus voltage Vfoc1 to the first focusing electrode 16 from the outside via the electrode pin 1061 (see FIG. 31), thereby causing a dielectric breakdown between the electrode pins 1061 and 1062. Since it does not occur, the problem of the present invention is solved.

  As a result, there is no need to fold the dynamic focusing voltage Vdyn1 on the first focusing electrode 16 to reduce the potential difference with the second focusing electrode 17 as in the first and second embodiments. Actually, due to the capacitance between the electrodes, the focus voltage Vfoc1 of the first focusing electrode 16 increases as the focus voltage Vfoc2 of the second focusing electrode 17 increases. As a result, the first focusing is performed. Since the action of the quadrupole lens between the electrode 16 and the second focusing electrode 17 becomes weak and overfocusing occurs particularly in the peripheral portion in the horizontal direction, the optimum focus cannot be obtained with the conventional electrode configuration as shown in FIG.

Therefore, also in the electron gun according to the present embodiment, it is basically necessary to give the main lens the second quadrupole lens action as in the first and second embodiments.
An example in which the above configuration is applied to an OLF lens type electron gun corresponding to FIG. 9 will be described.
FIG. 14 is a longitudinal sectional view of the electrode configuration of the electron gun 64 according to the present embodiment.

As shown in the figure, the shield cup 19 to which the anode voltage Va is applied is grounded via resistors R1 and R2 connected in series, and the voltage Vd = (R1 / (R1 + R2)) at the connection point between the resistors R1 and R2. XVa is applied to the first focusing electrode 16.
The resistors R1 and R2 are housed in the neck portion 5 together with the electron gun 64. An appropriate electrode pin in the electrode pin group 1063 (FIG. 31) is used as the electrode pin for grounding the resistor R1.

An equivalent circuit as shown in FIG. 15 is formed by the capacitance C1 between the acceleration electrode 15 and the first focusing electrode 16 and the capacitance C2 between the first focusing electrode 16 and the second focusing electrode 17, On the first focusing electrode 16, Vd ′ represented by the following expression 1 is superimposed on the voltage Vd obtained by resistance division.
Vd '= C2 / Vdyn2 / (C1 + C2) (Formula 1)
Since the dynamic focus voltage Vdyn2 is superimposed on the second focus voltage Vfoc2, the voltage Vd ′ superimposed on the first focusing electrode 16 also fluctuates with the fluctuation ratio of the weight ratio with respect to the dynamic focus voltage Vdyn2. It will be. Thereby, the relationship between the focus voltages Vfoc1 and Vfoc2 is substantially the same as the change in the focus voltage shown in FIG. 4 (however, the variation rate of Vfoc1 depends on the above equation 1).

Therefore, also in the present embodiment, the potential difference between the focus voltages of the first focusing electrode 16 and the second focusing electrode 17 is reduced during the deflection of the electron beam, and the first quadrupole lens action formed in this portion is the above-described effect. Insufficient to correct beam spot deformation.
Therefore, also in the present embodiment, as in the first and second embodiments, the main lens has the second quadrangle so as to compensate for the decrease in the first quadrupole lens action between the first focusing electrode 16 and the second focusing electrode 17. It is necessary to have a quadrupole lens action.

Therefore, in the present embodiment, the retraction distance L1 of the correction electrode 20 from the end surface 173 of the second focusing electrode 17 is the final value of the correction electrode 21, as in the modification shown in FIG. 9 of the first embodiment. The main lens is configured to have a second quadrupole lens action so as to be larger than the receding distance L2 from the end face 183 of the acceleration electrode 18.
Of course, it is needless to say that the other configuration described in the first embodiment may be adopted to create the second quadrupole lens action.

  When the electron beam is not deflected, the first quadrupole lens action formed by the first focusing electrode 16 and the second focusing electrode 17 and the main lens formed between the second focusing electrode 17 and the final acceleration electrode 18 are formed. The values of the resistors R1 and R2 are determined so that the focus voltage Vfoc1 is applied to the first focusing electrode 16 so that the second quadrupole lens component included in the first and second lenses is canceled in the horizontal and vertical directions.

(Modification of the third embodiment)
The configuration in which the focus voltage Vfoc1 of the first focusing electrode 16 is supplied by dividing the anode voltage Va by resistance in this manner can be similarly applied to the configuration of other electron guns that are not the OLF lens system.
FIG. 16 shows, as a modification of the third embodiment, the first focusing electrode 16 and the intermediate electrode by resistance division from the anode voltage Va in the EX-OLF lens type electron gun according to the second embodiment. It is a figure which shows the structure which supplies the voltage applied to a.

As shown in the figure, here, the shield cup 19 to which the anode voltage Va is applied is grounded via resistors R1, R3, and R4 connected in series, whereby the resistance-divided voltages Vd and Ve are obtained. These are applied to the first focusing electrode 16 and the intermediate electrode 24, respectively.
As described in the equivalent circuit of FIG. 15 above, the first focusing electrode 16 is applied with Vfoc1, which changes following the focus voltage Vfoc2 applied to the second focusing electrode 17. Further, when the capacitance between the second focusing electrode 17 and the intermediate electrode 24 is C3 and the capacitance between the intermediate electrode 24 and the final acceleration electrode 18 is C4, an equivalent circuit as shown in FIG. 17 is established. As a result, Ve ′ represented by the following expression 2 is superimposed on the resistance-divided voltage Ve and applied to the intermediate electrode 24 as the voltage Vm.

Ve ′ = C3 · Vdyn2 / (C3 + C4) (Formula 2)
Therefore, in this modification, not only the focus electrode Vfoc1 of the first focusing electrode 16 but also the voltage Vm applied to the intermediate electrode 24 varies with the variation of the focus voltage Vfoc2 applied to the second focusing electrode 17. It will be.
FIG. 18 is a schematic diagram showing how the focus voltages Vfoc1 and Vfoc2 applied to the first focusing electrode 16, the second focusing electrode 17, and the intermediate electrode 24, and the voltage Vm of the intermediate electrode are changed in the present modification. As shown in the figure, Vm rises as Vfoc2 rises. Therefore, the potential difference between the two when scanning the peripheral portion is larger than when the voltage Vm applied to the intermediate electrode 24 is constant.

  Therefore, the second quadrupole lens action formed between the second focusing electrode 17 and the final acceleration electrode 18 does not deteriorate so much at the peripheral portion of the screen, so that the periphery when the first and second quadrupole lenses are combined. Although the focusing action in the horizontal direction and the diverging action in the vertical direction at the part are inevitably slightly weaker than in the case of FIG. 13, it is possible to improve the electron beam while preventing the dielectric breakdown between the electrode pins as compared with the conventional configuration. The focus state can be secured over the entire screen.

Also in this modification, when the electron beam is undeflected, the first quadrupole lens action formed by the first focusing electrode 16 and the second focusing electrode 17 and the second focusing electrode 17 and the intermediate electrode 24 are formed. The values of the resistors R1, R3, and R4 are determined so that the second quadrupole lens action included in the main lens is substantially canceled in the horizontal direction and the vertical direction, respectively.
Similarly, the necessary focus voltage Vfoc1 can be supplied to the electron guns having other configurations by resistance division.

<Fourth embodiment>
The fourth embodiment is characterized in that Vfoc1> Vfoc2 is set when the electron beam is not deflected. Therefore, the first quadrupole lens has a diverging action in the horizontal direction and a focusing action in the vertical direction when there is no deflection, and the main lens has a focusing action in the horizontal direction and a vertical direction in order to cancel this lens action. The horizontal action, that is, the action opposite to the lens action in each of the above-described embodiments is formed.

Even in this case, when the electron beam is deflected to the peripheral portion, the quadrupole lens action in the first quadrupole lens and the main lens is synthesized to produce a converging force in the vertical direction and a diverging action in the horizontal direction. It is possible to correct the deformation of the beam spot due to the distortion.
Hereinafter, the contents of the electron gun according to the present embodiment will be described in detail using an EX-OLF lens type electron gun as an example.

    FIG. 19 is a longitudinal sectional view showing an electrode configuration of the electron gun 66 according to the present embodiment. Here, (a) the shape of the electron beam passage hole of the correction electrode 20 is made to be relatively horizontally longer than the shape of the electron beam passage hole of the correction electrode 25 (see FIG. 6A), and (b). The relationship between the receding distances L1 and Lm from the openings of the correction electrodes 20 and 25 is set so that L1> Lm. Thus, the diverging action in the horizontal direction between the second focusing electrode 17 and the intermediate electrode 24, and the vertical A second quadrupole lens L2 having a focusing effect in the direction is formed.

It should be noted that even if both of the above conditions (a) and (b) are not satisfied, by adjusting the shape of the electron beam passage hole and the relative amount of L1 and Lm, the same degree can be obtained under only one of the conditions. Needless to say, the second quadrupole lens L2 having the above lens action can be formed.
The shape of the electron beam passage hole formed in the opposing surface of the first focusing electrode 16 and the second focusing electrode 17 is the same as that shown in FIG.

In the present embodiment, the structural difference from the electron gun 63 shown in FIG. 13 is particularly different between the intermediate electrode 24 and the final accelerating electrode 18, in which the focusing action is horizontal and the divergence is vertical. A third quadrupole lens is formed, and the third quadrupole lens action is set to be larger than the second quadrupole lens action.
Specifically, (1) the electron beam passage holes 21 a, 21 b, 21 c provided in the correction electrode 21 are relative to the electron beam passage holes 25 a, 25 b, 25 c provided in the correction electrode 25 of the intermediate electrode 24. (2) A partition electrode 26 is formed on the shield cup 19 side of the correction electrode 21 of the final acceleration electrode 18 (see FIG. 25A described later).

  As shown in the perspective view of FIG. 20, the screen-type electrode 26 has a pair of electrode plates 26a and 26b arranged in parallel in the horizontal direction and three electron beam passage openings 191 of the shield cup 19 vertically (vertical direction). ) Is attached to the end surface of the shielded cup 19 on the final acceleration electrode 18 side by welding or the like. When the shield cup 19 is attached to the final acceleration electrode 18, the electrode plates 22a and 22b are subjected to final acceleration. The electrode plates 22a and 22b are inserted into the openings of the electrode 18 and viewed from the tube axis direction so that the electrode plates 22a and 22b are positioned so as to sandwich the electron beam passage holes 21a to 21c from above and below.

First, with the configuration of (1), a quadrupole lens component is generated between the correction electrode 25 and the final acceleration electrode 18 that has a focusing action in the horizontal direction and a diverging action in the vertical direction.
Further, due to the configuration of the screen-type electrode (2), the pair of electrode plates 22a and 22b extending in the traveling direction of the electron beam causes the electron beam to be diverged in the vertical direction under the influence of the high potential. A quadrupole lens component having a focusing action in the horizontal direction and a diverging action in the vertical direction is generated.

Here, a lens obtained by combining the respective quadrupole lens components generated by the configurations of (1) and (2) is defined as a third quadrupole lens.
The second and third quadrupole lenses are 90 ° different from each other in the direction of focusing and diverging action, but the third quadrupole lens is generated by both configurations (1) and (2). As a result, when the second and third quadrupole lenses are combined, a quadrupole lens having a weak focusing action in the horizontal direction and a weak diverging action in the vertical direction is obtained.

  Therefore, in the present embodiment, as shown in FIG. 21, when the electron beam is not deflected, the focus voltage Vfoc1 is set higher than the potential of Vfoc2, and is generated between the first focusing electrode 16 and the second focusing electrode 17. The first quadrupole lens action has a diverging action in the horizontal direction and a focusing action in the vertical direction, and cancels out in the horizontal and vertical directions with the combined lens action of the second and third quadrupole lenses. I am doing so.

FIGS. 22A and 22B are diagrams for explaining the lens action in the present embodiment.
Unlike the case of FIG. 7, here, the main lens Lm can be regarded as a combined lens of the second quadrupole lens L2, the third quadrupole lens L3, and the axially symmetric focusing lens L4.
First, when the electron beam is at the center of the screen (no deflection), since the focus voltage Vfoc1> Vfoc2 as described above, the first quadrupole lens L1 formed between the first and second focusing electrodes 16 and 17 is 22 (a), it has a diverging action in the horizontal direction and a focusing action in the vertical direction. Similarly, the second quadrupole lens L2 formed between the second focusing electrode 17 and the final acceleration electrode 18 also has a diverging action in the horizontal direction and a focusing action in the vertical direction. The third quadrupole lens L3 formed between the intermediate electrode 24 and the final acceleration electrode 18 has a focusing action in the horizontal direction and a diverging action in the vertical direction.

As described above, at the time of no deflection, the electron beam is not subjected to the action of deforming the beam spot by the deflection magnetic field, so that it is not necessary to correct this beforehand by the action of the quadrupole lens in the electron gun. Each quadrupole lens forming condition is set so that the lens action is canceled in the vertical and horizontal directions when the third quadrupole lens is synthesized.
When the amount of deflection of the electron beam increases, both the focus voltages Vfoc1 and Vfoc2 increase as shown in FIG. 21, but since the increase rate of Vfoc2 is larger than the increase rate of Vfoc1, A, -A (the center of the screen is changed). When “0” is set, the right direction of the screen is positive and the left direction is negative.) Vfoc2> Vfoc1, and thereafter, the first quadrupole lens L1 has a horizontal focusing function and a vertical direction. Diverges and the electron beam is further deflected, thus strengthening their quadrupole lens action.

On the other hand, the increase in Vfoc2 applied to the second focusing electrode 17 weakens the lens action of the second quadrupole lens L2, but the third quadrupole lens L3 is formed between the intermediate electrode 24 and the final acceleration electrode 18. Therefore, it is difficult to be affected by the increase in Vfoc2 applied to the first focusing electrode 16, and the magnitude of the quadrupole lens action does not change much.
Therefore, finally, at the periphery of the screen, as shown in FIG. 22B, the first quadrupole lens L1 has a focusing action in the horizontal direction and a diverging action in the vertical direction, while the second and third In the composite component of the quadrupole lens, the horizontal focusing action and the vertical divergence action are stronger, and they combine to correct the deformation of the beam spot caused by the deflection magnetic field distortion at the periphery of the screen. Therefore, a sufficient quadrupole lens action can be obtained.

As a result, an optimum focus state of the electron beam can be obtained over the entire screen.
According to the present embodiment, since the potential of the focus voltage Vfoc2 applied to the second focusing electrode 17 is lowered, the following secondary effect can also be obtained.
That is, as shown in FIG. 21, since there is a section where Vfoc2 <Vfoc1, the rate of increase in voltage necessary for maintaining a good focus state in this portion can be kept low, and as a result, the peripheral portion of the screen is good. It is possible to reduce the maximum voltage of the dynamic focus voltage Vdyn2 necessary for maintaining a stable focus state. In addition, since the maximum voltage of the dynamic focus voltage Vdyn1 can be reduced accordingly, the configuration of the dynamic focus voltage circuit can be simplified as a whole, and the power consumption for generating each dynamic focus voltage can be reduced. Is obtained. Therefore, hereinafter, in this specification, an electron gun in which the focus voltage Vfoc2 is lower than the focus voltage Vfoc1 at least when the electron beam is not deflected is referred to as an “electron-saving electron gun”.

In the above description, the screen-type electrode 26 is provided on the end face of the shield cup 19, but in the same manner as shown in FIG. 11, the correction electrode 21 of the final acceleration electrode 18 or the opposite side (first side) It may be provided on the second focusing electrode 17 side.
Further, means for forming a third quadrupole lens having a diverging action in the horizontal direction and a focusing action in the vertical direction between the second focusing electrode 17 and the final accelerating electrode 18 includes the electron beam passage hole of the correction electrode as described above. It is not limited only to the shape and the attachment of the partition-type electrode 26, but can be achieved by applying other known configurations.

The conditions for giving the main lens the optimum quadrupole lens action in each of the above embodiments can be obtained by experiments and simulations. Specific examples thereof include the electron gun of FIG. 14 and the electron gun of FIG. In the example of the power-saving electron gun shown in FIG. 19, a case where a voltage such as Vfoc1 is supplied by resistance division will be described.
The dimensions of each part of the electron gun in each example are shown for a color cathode ray tube apparatus having a screen size of 32 inches and a maximum deflection angle of 102 °.

Example 1
FIG. 23A is a longitudinal sectional view showing the main part of the electrode configuration of the electron gun shown in FIG. 14 and a front view of each correction electrode. For the sake of simplicity, the first focusing electrode 16 is shown in appearance, The other electrodes are not shown.
The voltages V1 and V2 applied to the first focusing electrode 16 and the second focusing electrode 17 and the anode voltage Va applied to the final acceleration electrode 18 when the electron beam is not deflected are shown in the table of FIG. Thus, the maximum values of the dynamic focus voltage Vdyn2 (the voltage at the time of scanning the peripheral portion of the screen) which are superimposed on V2 of the second focusing electrode 17 are 1.35 kV, respectively, 7.8 kV, 9.0 kV and 30.5 kV. Set to

  In addition, the correction electrodes 20 and 21 are formed on the retraction distances L1 and L2 (L1> L2) from the opposing ends of the second focusing electrode 17 and the final acceleration electrode 18 and the correction electrodes 20 and 21, respectively. The vertical diameter cV and the horizontal diameter cH of the central (center) electron beam passage hole, the vertical diameter sV of the electron beam on both sides thereof, the horizontal diameter sH, and the electron beam passage hole The pitch P between them is as shown in the table of FIG.

Thus, in the OLF type electron gun, the second quadrupole lens is properly formed on the main lens, and there is no risk of dielectric breakdown between the electrode pins. The shape can be obtained, and the image resolution on the entire screen is improved.
(Example 2)
FIG. 24A is a longitudinal sectional view showing the main part of the electrode configuration of the electron gun shown in FIG. 16 and a front view of each correction electrode. Like the first embodiment, the first focusing electrode 16 is externally shown for the sake of simplicity. The other electrodes are not shown.

  When the electron beam is not deflected, voltages V1, V2, and Vm applied to the first focusing electrode 16, the second focusing electrode 17, and the intermediate electrode 24 and the anode voltage Va applied to the final acceleration electrode 18 are shown in FIG. As shown in the table of b), they are 5.7 kV, 7.0 kV, 13.4 kV, and 30.5 kV, respectively, and the maximum value of the dynamic focus voltage Vdyn convolved with V2 of the second focusing electrode 17 is 1. Set to 45 kV.

  Further, as shown in FIG. 24A, the retreat distances from the end portions of the outer peripheral electrodes of the correction electrodes 20, 25, and 21 are L1, Lm, and L2, and the center formed on each of the correction electrodes 20, 25, and 21 is formed. The vertical diameter cV and the horizontal diameter cH of the (center) electron beam passage hole, the vertical diameter sV of the electron beam on both sides thereof, the size of the horizontal diameter sH, and the space between the electron beam passage holes The pitch P is set as shown in the table of FIG.

As a result, in the EX-OLF lens type electron gun, the second quadrupole lens is properly formed on the main lens, and there is no risk of dielectric breakdown between the electrode pins. A beam spot shape can be obtained, and the image resolution on the entire screen is improved.
Example 3
FIG. 25A is a longitudinal sectional view showing the main part of the electrode configuration when the voltages Vfoc1 and Vm are supplied by resistance division in the power-saving EX-OLF lens type electron gun shown in FIG. It is the front view of this, and the top view and front view of a partition-type electrode.

  When the electron beam is not deflected, the voltages V1 and V2 applied to the first focusing electrode 16 and the second focusing electrode 17, the voltage Vm applied to the intermediate electrode 24, and the anode voltage Va applied to the final acceleration electrode 18 are: As shown in the table of FIG. 25B, they are 7.2 kV, 7.0 kV, 13.4 kV, and 30.5 kV, respectively, and the maximum of the dynamic focus voltage Vdyn2 that is superimposed on the voltage V2 of the second focusing electrode 17 The value is set to 1.10 kV.

Thus, in this example, since the voltage V1> V2 when the electron beam is not deflected, the maximum voltage of the dynamic focus voltage Vdyn2 is 1.1 kV, which is about 24% that of the first and second embodiments. It is about 27% lower. As described above, this simplifies the dynamic focus voltage circuit and contributes to power saving.
Further, the vertical directions of the center (center) electron beam passage holes formed in the receding distances L1, Lm, L2 from the outer peripheral electrode ends of the correction electrodes 20, 25, 21 and the correction electrodes 20, 25, 21, respectively. And the horizontal diameter cH, the vertical diameter sV of the electron beam on both sides thereof, the size of the horizontal diameter sH, the pitch P between the electron beam passage holes, and the shield cup 19. The dimensions of the screen-type electrode 26 are set as shown in the table of FIG.

As a result, in the EX-OLF lens system and the power-saving electron gun, the second and third quadrupole lenses are properly formed on the main lens, and there is no risk of dielectric breakdown between the electrode pins. The optimum focus state and beam spot shape can be obtained throughout, and the image resolution on the entire screen is improved.
<Others>
(1) The configuration in which the electron gun has the first, second, or third quadrupole lens action is not limited to the above. For example, in the example of FIG. 10, a partition electrode 27 is provided to sandwich the electron beam passage hole of the correction electrode 20 of the second focusing electrode 17 from above and below in order to form a second quadrupole lens. Thus, the electrode plates 22a, 22b, 22c, 22d, 22e, and 22f are erected so as to sandwich the electron beam passage holes 21a, 21b, and 21c of the correction electrode 21 on the final acceleration electrode 18 side from the horizontal direction. The same effect can be obtained. Moreover, it is also possible to use a plurality of different configurations in combination at one quadrupole lens forming portion as required.

Note that if the focus state of at least one electron beam is improved, it can be said that the resolution is improved as compared with the prior art. Therefore, the configuration of each quadrupole lens may not be applied to all electron beams. It is possible.
(2) The correction electrode for forming the OLF lens (or EX-OLF lens) is not necessarily provided on all the cylindrical electrodes constituting the main lens, and the correction electrode is provided on at least one cylindrical electrode. If provided, an OLF lens can be formed. Further, the correction electrode is not limited to the above-described plate shape, and may be a screen type.

   (3) In each of the above embodiments, the example in which the cathodes of the electron gun are arranged inline in the horizontal direction has been described. Recently, however, a cathode ray tube apparatus having a configuration in which the cathodes are arranged inline in the vertical direction has been devised. In this case, the deflection magnetic field for self-convergence is also tilted by 90 ° about the tube axis, the horizontal deflection magnetic field is distorted in a barrel shape, and the vertical deflection magnetic field is distorted in a pin cushion shape. Yes.

In this case, each electron beam passing through the deflection magnetic field is focused in the horizontal direction and diverged in the vertical direction, so that the vertical and horizontal directions of the action of the first and second quadrupole lenses in the peripheral portion of the screen. The lens action is configured to be just opposite to that described in the above embodiment.
(4) In the above embodiments, the OLF lens or the EX-OLF lens type electron gun has been described. However, even in a normal electron gun that does not include a correction electrode inside the cylindrical electrode that forms the main lens, It is possible to include a quadrupole lens action as described above. In this case, for example, if the shape of each electron beam passage hole (see FIG. 2) provided in the shield cup 19 is a vertically long shape, the electron beam passage hole on the first focusing side end face of the second focusing electrode 17 is horizontally long. In combination with the shape (see FIG. 5B), the second quadrupole lens action can be provided.

  According to the electron gun of the present invention, even if the dynamic focus voltage increases with an increase in the maximum deflection amount of the electron beam, good resolution is achieved over the entire screen without causing dielectric breakdown between the electrode pins. Therefore, it is particularly suitable as an electron gun for a color picture tube device having a flat screen and a large size.

1 is a half sectional view showing a schematic configuration of a color cathode ray tube apparatus according to a first embodiment of the present invention. It is a perspective view of the electron gun in the said color cathode ray tube. It is a longitudinal cross-sectional view which shows the electrode structure of the said electron gun. It is a figure which shows the mode of the change of the focus voltages Vfoc1 and Vfoc2 which are applied to each of the 1st focusing electrode and the 2nd focusing electrode of the said electron gun. (A), (b) is a figure which shows the shape of the electron beam passage hole formed in the end surface which the said 1st focusing electrode and the 2nd focusing electrode oppose, respectively. (A), (b) is a figure which shows the shape of the electron beam passage hole of the correction electrode arrange | positioned in the 2nd focusing electrode and the final acceleration electrode in the said electron gun. (A), (b) shows the lens action of the first quadrupole lens and the main lens formed by the electron gun according to the first embodiment, respectively, when the electron beam irradiates the center of the screen (no deflection) And the electron beam is deflected to the periphery of the screen. It is a block diagram which shows the structure of the dynamic focus voltage circuit in the picture tube apparatus which concerns on 1st Embodiment. It is a longitudinal cross-sectional view which shows the principal part of the electrode structure in the modification 1 of the electron gun which concerns on 1st Embodiment. It is a longitudinal cross-sectional view which shows the principal part of the electrode structure in the modification 2 to the electron gun which concerns on 1st Embodiment. It is a perspective view which shows the shape of the screen type electrode in the electron gun of FIG. (A), (b) is a figure which respectively shows the shape which looked at the outer periphery electrode of the 2nd focusing electrode and the final acceleration electrode in the modification 3 of the electron gun which concerns on 1st Embodiment from the tube-axis direction. . It is a longitudinal cross-sectional view which shows the electrode structure of the electron gun which concerns on 2nd Embodiment. It is a longitudinal cross-sectional view which shows the electrode structure of the electron gun which concerns on 3rd Embodiment. FIG. 14 is a diagram showing an equivalent circuit formed by the capacitance formed between the acceleration electrode and the first focusing electrode and the capacitance formed between the first focusing electrode and the second focusing electrode. It is. It is a longitudinal cross-sectional view which shows the electrode structure of the electron gun which concerns on the modification of 3rd Embodiment. In FIG. 16, it is a figure which shows the equivalent circuit formed with the electrostatic capacitance formed between a 2nd focusing electrode and an intermediate electrode, and the electrostatic capacitance formed between an intermediate electrode and a final acceleration electrode. . It is a figure which shows the mode of the change of the focus voltages Vfoc1, Vfoc2, and Vm applied to each of the 1st focusing electrode of the electron gun of FIG. 16, a 2nd focusing electrode, an intermediate electrode, and the final acceleration electrode. It is a longitudinal cross-sectional view which shows the electrode structure of the electron gun which concerns on 4th Embodiment. It is a perspective view of the shield cup for showing the shape of the screen type electrode in FIG. 19, and the mode of attachment. It is a figure which shows the mode of the change of the focus voltages Vfoc1 and Vfoc2 which are applied to each of the 1st focusing electrode and 2nd focusing electrode of the electron gun of FIG. (A), (b) explains the lens action of the first quadrupole lens and the main lens in the electron gun according to the fourth embodiment when the electron beam scans the screen center and the screen periphery. FIG. It is a figure for demonstrating Example 1 of the electron gun which concerns on this invention, (a) is a schematic longitudinal cross-sectional view of the principal part of the said electron gun, (b) shows the voltage value applied to each electrode of an electron gun. Table (c) is a list of dimensions for indicating the position of each correction electrode, the shape of the electron beam passage hole, and the like. It is a figure for demonstrating Example 2 of the electron gun which concerns on this invention, (a) is a schematic longitudinal cross-sectional view of the principal part of the said electron gun, (b) is the voltage value applied to each electrode of an electron gun. Table (c) is a list of dimensions for indicating the position of each correction electrode, the shape of the electron beam passage hole, and the like. It is a figure for demonstrating Example 3 of the electron gun which concerns on this invention, (a) is a schematic longitudinal cross-sectional view of the principal part of the said electron gun, (b) is the voltage value applied to each electrode of an electron gun. Table (c) is a list of dimensions for indicating the position of each correction electrode, the shape of the electron beam passage hole, and the like. It is a perspective view of the auxiliary electrode for showing another example of the screen type electrode for forming a quadrupole lens. It is a longitudinal cross-sectional view which shows the electrode structure of the conventional electron gun. (A), (b) is a figure which shows the shape of the electron beam passage hole formed in the end surface which the 1st focusing electrode and the 2nd focusing electrode in a conventional electron gun oppose, respectively. It is a figure which shows the mode of the change of focus voltage Vfoc1 applied to each of the 1st focusing electrode and the 2nd focusing electrode of the said conventional electron gun. (A), (b) is a figure for demonstrating the case where an electron beam scans a screen center part and a screen peripheral part, respectively about the lens action of the 1st quadrupole lens and main lens in a conventional electron gun. . It is a figure which shows the mode of the arrangement | sequence of the electrode pin standingly arranged by the glass material with which the neck part edge part of the cathode ray tube was mounted | worn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color cathode ray tube apparatus 4 Phosphor screen 5 Neck part 6, 61-67, 100 Electron gun 11-13 Cathode 14 Control electrode 15 Acceleration electrode 16 1st focusing electrode 17 2nd focusing electrode 18 Final acceleration electrode 19 Shield cup 24 Intermediate Electrode 20, 21, 25 Correction electrode 22, 26 Screen electrode 200 Dynamic focus voltage circuit 201 Horizontal parabola voltage generation circuit 202 Vertical parabola voltage generation circuit 203 Adder 204, 205 Resistance 206 High voltage generation circuit

Claims (15)

A plurality of cathodes housed in a neck portion of the cathode ray tube and arranged in-line in a first direction orthogonal to the tube axis of the cathode ray tube, a first focusing electrode, a second focusing electrode, and a main lens forming portion The first and second focusing electrodes have a focusing action in the first direction when the electron beam is not deflected, and have a diverging action in the first direction and the second direction orthogonal to the tube axis. An electron gun in which a quadrupole lens electric field of 1 is formed and a focus voltage that gradually increases with an increase in the amount of deflection of the electron beam is applied to the second focusing electrode,
A voltage having a potential lower than the focus voltage applied to the second focusing electrode and having a smaller potential increase rate than the focus voltage is applied to the first focusing electrode,
The main lens forming portion has a plurality of cylindrical electrodes to which a higher voltage is applied as it goes to the subsequent stage in the traveling direction of the electron beam,
The at least one pair of adjacent cylindrical electrodes of the plurality of cylindrical electrodes has a focusing action in the first direction in the second direction according to a potential difference between the low potential side electrode and the high potential side electrode. An electron gun configured to form a second quadrupole lens electric field weaker than a focusing action at least when the electron beam is not deflected.   2. The electron gun according to claim 1, wherein when the electron beam is not deflected, a focusing force obtained by combining the first and second quadrupole lens electric fields is substantially equal in the first and second directions.   3. The electron gun according to claim 1, wherein a potential difference between voltages applied to the first and second focusing electrodes is approximately 2 kV or less during maximum deflection of the electron beam. For the adjacent pair of cylindrical electrodes,
The shape of the cross section of the cylindrical electrode on the low potential side is flattened in the second direction relative to the shape of the cross section of the cylindrical electrode on the high potential side. 4. The electron gun according to any one of 3. For the adjacent pair of cylindrical electrodes,
A plate-like correction electrode in which a plurality of electron beam passage holes through which the plurality of electron beams pass is formed inside each is disposed at a position retracted from the opposing end surfaces of the pair of cylindrical electrodes,
At least one of the plurality of electron beam passage holes of the correction electrode of the low-potential side cylindrical electrode has a ratio of the inner diameter in the first direction to the inner diameter in the second direction. The electron gun according to any one of claims 1 to 4, wherein the electron gun is set to be larger than a ratio of a correction electrode to a corresponding electron beam passage hole. A plurality of electron beams through which each of the plurality of electron beams passes inside the first cylindrical electrode on the low potential side and the second cylindrical electrode on the high potential side with respect to at least a pair of adjacent cylindrical electrodes. The plate-like correction electrode in which the passage hole is formed is disposed at a position retracted by the first distance and the second distance from the opposing end surfaces of the pair of cylindrical electrodes, respectively.
6. The electron gun according to claim 1, wherein the first distance is set to be larger than the second distance. About the at least one pair of adjacent cylindrical electrodes, plate-like correction electrodes each having therein a plurality of electron beam passage holes through which the plurality of electron beams pass are end faces facing the pair of cylindrical electrodes. Arranged at a position retracted from
7. The correction electrode of the cylindrical electrode on the low potential side is provided with a screen-like electrode standing upright so as to sandwich the plurality of electron beam passage holes from above and below. The electron gun according to any one of the above.   The electron gun according to any one of claims 1 to 7, wherein the second focusing electrode also serves as the cylindrical electrode on the low potential side. A plurality of cathodes housed in a neck portion of the cathode ray tube and arranged in-line in a first direction orthogonal to the tube axis of the cathode ray tube, a first focusing electrode, a second focusing electrode, and a main lens forming portion And the first and second focusing electrodes have a diverging action in the first direction when the potential of the first focusing electrode is higher than the potential of the second focusing electrode. A first quadrupole lens electric field having a focusing action is formed in a second direction orthogonal to the axis, and a focus voltage that gradually increases as the amount of deflection of the electron beam increases is applied to the second focusing electrode. An electron gun,
The first focusing electrode is applied with a voltage having a lower rate of potential increase than the focus voltage applied to the second focusing electrode, and at least a voltage higher than the focus voltage when the electron beam is not deflected,
An electron gun characterized in that a main lens electric field formed by the main lens forming portion is configured such that the focusing action in the first direction is stronger than the focusing action in the second direction. The main lens forming portion is formed by arranging first, second, and third cylindrical electrodes in this order along the traveling direction of the electron beam,
Between the first and second cylindrical electrodes, a second quadrupole lens electric field is formed in which the focusing action in the second direction is stronger than the focusing action in the first direction;
Between the second and third cylindrical electrodes, a third quadrupole lens electric field is formed in which the focusing action in the first direction is stronger than the focusing action in the second direction,
10. The configuration according to claim 9, wherein when the second and third quadrupole lens electric fields are combined, the focusing action in the first direction is stronger than the focusing action in the second direction. The electron gun described.   11. The electron gun according to claim 10, wherein the second focusing electrode also serves as a first cylindrical electrode in the main lens forming portion.   The first focusing electrode is connected to an electrode to which the highest potential is applied in the electron gun via a first resistor, and is connected to a ground electrode pin via a second resistor, whereby the highest potential is obtained. The electron gun according to claim 1, wherein the voltage is divided by resistance and a predetermined voltage is applied to the first focusing electrode. A color picture tube device comprising a cathode ray tube containing an electron gun in a neck portion, and a deflection device for deflecting an electron beam emitted from the electron gun horizontally and vertically,
While the electron gun according to any one of claims 1 to 11 is used as the electron gun,
First voltage supply means for supplying, to the second focusing electrode of the electron gun, a focus voltage whose potential gradually increases as the amount of deflection of the electron beam increases;
2. A color image receiving device comprising: a second voltage supply means for supplying a voltage that changes following the focus voltage at a rate of increase smaller than the rate of increase of the focus voltage to the first focusing electrode. Tube equipment.   The first voltage supply means and the second voltage supply means have a first quadrupole lens electric field formed between the first and second focusing electrodes and a main lens portion formed when the electron beam is not deflected. 14. A voltage is supplied to each of the first and second focusing electrodes such that when the lens electric fields are combined, the magnitude of the focusing action in the first and second directions is approximately equal. A color picture tube device according to claim 1.   In the electron gun, the first focusing electrode is connected to the electrode to which the highest potential is applied in the electron gun via the first resistor, and is connected to the ground electrode pin via the second resistor. Thus, the voltage of the highest potential is resistance-divided and a predetermined voltage is applied to the first focusing electrode, and the second voltage supply means includes the first and second connected in series. 15. The color picture tube apparatus according to claim 13, wherein the color picture tube apparatus is a voltage distribution circuit made of a resistor.

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