JPH11297229A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good and uniform focus throughout the entire screen area. SOLUTION: A good and uniform focus is provided for the entire screen area by composing a first kind focusing electrode group from a first electrode 41 and a third electrode 43, composing a second kind focusing electrode group from a second electrode 42 and a fourth electrode 44, applying a first focusing voltage formed from a constant voltage Vf1 to the first kind focusing electrode group and also applying, to the second kind focusing electrode group, a second focusing voltage provided by adding a dynamic voltage dVf varying synchronized with the deflection of an electron beam to a constant voltage Vf2, installing a first static quadrupole lens 8 in the second kind focusing electrode group and also installing a second static quadrupole lens 9 in the first kind focusing electrode group, arranging a main lens 7, the first static quadrupole lens 8 and the second static quadrupole lens 9 in that order, and imparting a very strong electron beam reshaping action to the second static quadrupole lens 9 formed in the first kind focusing electrode group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube having an electron gun for emitting an electron beam to a phosphor screen, and more particularly to a color cathode ray tube having an electron gun capable of obtaining good focus over the entire screen.

[0002]

2. Description of the Related Art In a color cathode ray tube such as a television picture tube or a display tube, light is emitted from an electron gun so that a high resolution can be obtained with good focusing characteristics (focus characteristics) over the entire screen constituting the screen. It is necessary to properly control the spot shape of the electron beam on the screen in accordance with the magnitude of the deflection amount.

FIG. 7 is a schematic sectional view taken along a tube axis for explaining the structure of an electron gun used in a conventional high resolution color cathode ray tube. The cathode 1, control electrode 2, accelerating electrode 3, focusing electrode First electrode 41 and second electrode 4 forming group 4
2, a third electrode 43, a fourth electrode 44, an anode electrode 5, and a shield cup 6, and a main lens is formed at a portion where the fourth electrode 44 and the anode electrode 5 are opposed to each other. The first electrode 41 and the third
The electrode 43 constitutes a first type focusing electrode group, and the second electrode 42 and the fourth electrode 44 constitute a second type focusing electrode group. Further, a lens is formed between the first electrode 41 and the second electrode 42 and between the third electrode 43 and the fourth electrode 44 so that the focusing power for focusing in both the horizontal direction and the vertical direction is increased. Between the electrode 42 and the third electrode 43, there is provided an electrostatic quadrupole lens that acts on the electron beam so as to diverge in the horizontal direction and focus in the vertical direction.

Then, a first focusing voltage Vf1 of a constant voltage is applied to the first electrode 41 and the third electrode 43 constituting the first kind of focusing electrode group, and the second focusing electrode Vf1 constituting the second kind of focusing electrode group is formed. A second focusing voltage Vf2 + dVf is applied to the electrode 42 and the fourth electrode 44, which is obtained by adding a dynamic voltage dVf that fluctuates in synchronization with a change in the deflection angle for scanning the electron beam on the screen to a constant focusing voltage Vf2.

FIG. 8 is a waveform diagram of the focusing voltage applied to the electron gun shown in FIG. 7, wherein the first focusing voltage Vf1 is considerably larger than the second focusing voltage Vf2 + dVf, and (Vf1)>
(Vf2 + dVf).

When the above-mentioned focusing voltage is applied to the electron gun, a dynamic voltage is applied to the lens formed between the first electrode 41 and the second electrode 42 and between the third electrode 43 and the fourth electrode 44. When the amount of deflection of the electron beam increases, that is, when the amount of deflection of the electron beam increases, the potential difference in the lens that increases the focusing power in both the horizontal direction and the vertical direction decreases, and the lens strength decreases. Therefore, the force for converging the electron beam is weakened when the electron beam is deflected, and the field curvature is corrected.

With this configuration, the astigmatism is corrected by the electrostatic quadrupole lens provided between the second electrode 42 and the third electrode 43 in accordance with the deflection angle of the electron beam, and the first lens is added to the main lens. Between the electrode 41 and the second electrode 42, between the third electrode 43 and the fourth electrode 4,
By correcting the field curvature aberration formed during the period 4, it is possible to obtain a color cathode ray tube always having good focus characteristics on a screen with a small dynamic voltage.

[0008]

However, in the above-described electron gun used in a conventional color cathode ray tube, the main effect of the electron gun is synchronized with the influence of deflection aberration and the amount of electron beam deflection by an electrostatic quadrupole lens. Since the cross-sectional shape of the electron beam incident on the lens also changes, it is difficult to obtain good and uniform focus over the entire screen.

Therefore, the first electrode 41 has a circular shape on the side of the second electrode 42 or a rectangular shape having a long axis in the horizontal direction.
An electron beam passage hole having the same elliptical shape or the same keyhole shape is provided, and the second electrode 42 has a circular shape on the first electrode 41 side, or a rectangular shape having a long axis in the vertical direction, the same elliptical shape, the same key. An application in which one of the hole-shaped electron beam passage holes is provided was filed earlier (Japanese Patent Application No. 9-246352).

FIG. 9 is a schematic diagram of a first electrode and a second electrode for explaining an example of the shape of the focusing electrode disclosed in the above-mentioned invention.

That is, here, the second electrode of the first electrode 41
On the electrode 42 side, rectangular electron beam passage holes 41a, 41b, 41c having a long axis in the horizontal direction are provided.
On the first electrode 41 side, there were provided rectangular electron beam passage holes 42a, 42b and 42c having a long axis in the vertical direction.

In such a configuration, an electrostatic quadrupole lens having a focusing action in the horizontal direction and a diverging action in the vertical direction is installed between the first electrode 41 and the second electrode 42 as an electron beam shaping lens. Thus, the cross-sectional shape of the electron beam incident on the main lens is shaped to obtain good and uniform focus over the entire screen.

However, any one of the above-mentioned circular shape, the rectangular shape having the major axis in the horizontal direction, the elliptical shape, and the keyhole shape, and the circular shape or the major axis in the vertical direction are provided. An electron beam shaping lens formed of a rectangular, elliptical, or keyhole-shaped electron beam passing hole has a limitation in increasing its lens strength, and provides good and uniform focus over the entire screen. It has been difficult to freely shape the cross-sectional shape of the electron beam so as to obtain. SUMMARY OF THE INVENTION It is an object of the present invention to provide a color cathode ray tube having an electron gun capable of solving the above-mentioned problems of the prior art and obtaining a good and uniform focus over the entire screen.

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a horizontally arranged and controlled three-dimensional array.
An electron having an electron beam generator (cathode 1, control electrode 2, acceleration electrode 3) for generating three electron beams and a main lens unit for focusing three electron beams generated by the electron beam generator on a phosphor screen. In a color cathode ray tube including at least a gun and a deflection yoke for scanning the three electron beams on a phosphor screen, the main lens portion of the electron gun has an anode (5) to which an anode voltage (Eb) is applied. )When,
A first type of focusing electrode group (first electrode 41 and third electrode 43) to which a first focusing voltage (Vf1) is applied, and a second type of focusing electrode to which a second focusing voltage (Vf2 + dVf) is applied A group (second electrode 42 and fourth electrode 44), and the anode (5) has an electrode (fourth electrode 44) belonging to the second type of focusing electrode group (second electrode 42 and fourth electrode 44). Are adjacent,
The second focusing voltage is a dynamic voltage (dVf) that changes to a constant voltage (Vf2) according to the deflection amount of the electron beam.
Are superimposed, and the first-type focusing electrode group (the first electrode 41 and the third electrode 43) and the second-type focusing electrode group (the second
The first type of focusing electrode group (the first electrode 41 and the third electrode 43) applied between the electrode 42 and the fourth electrode 44)
Focusing voltage (Vf1) and the second type focusing electrode group (second
As the potential difference between the second focusing voltage (Vf2 + dVf) applied to the electrode 42 and the fourth electrode 44) increases, the focusing surface for focusing the three electron beams in both the horizontal and vertical directions increases. With at least one curved lens, an electrostatic quadrupole that increases the converging force for converging the three electron beams in one of the horizontal direction and the vertical direction and further increases the diverging force diverging to the other one A first electrostatic quadrupole lens, wherein at least two lenses are formed, and among the electrostatic quadrupole lenses, the first electrostatic quadrupole lens acts to diverge in the horizontal direction with respect to the traveling direction of the electron beam and to converge in the vertical direction (8), and a second electrostatic quadrupole lens (9) that acts so as to converge in the horizontal direction and diverge in the vertical direction with respect to the traveling direction of the electron beam. Electric quadrupole len (8) and a second electrostatic quadrupole lens (9) are sequentially arranged from the main lens side, and the second electrostatic quadrupole lens (9) belongs to a first type focusing electrode group. At least one pair of horizontal electrode pieces (41) sandwiching each electron beam from above and below in the vertical direction in the electrode (first electrode 41).
1) and at least one pair of vertical electrode pieces (422) sandwiching each electron beam from both sides in the horizontal direction between the electrodes (second electrodes 42) belonging to the second type of focused electrode group.

With the above configuration, the function of shaping the electron beam of the second electrostatic quadrupole lens is enhanced, and the cross-sectional shape of the electron beam is freely shaped so that good and uniform focus can be achieved over the entire screen. Can be provided.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to examples.

FIG. 1 is a schematic cross-sectional view of an embodiment of an electron gun used for a color cathode ray tube according to the present invention, taken along a tube axis direction. FIG. It is a front view of a heavy pole part, 1 is a cathode, 2 is a control electrode,
3 is an accelerating electrode, 4 is a focusing electrode group, 41 is a first electrode 41,
The main lens is formed of the second electrode 42, the third electrode 43, the fourth electrode 44, the anode electrode 5, and the shield cup 6, and a main lens is formed at a portion where the fourth electrode 44 and the anode electrode 5 face each other. The first electrode 41 and the third electrode 43 form a first type of focusing electrode group, and the second electrode
The electrode 42 and the fourth electrode 44 constitute a second type of focusing electrode group.

Reference numeral 411 denotes a horizontal electrode provided on the second electrode 42 side of the first electrode 41 so as to sandwich each electron beam from above and below in the vertical direction, and 422 denotes a horizontal electrode provided on the first electrode 41 side of the second electrode 42. A vertical electrode 421 is provided so as to sandwich the beam from the horizontal direction. Reference numeral 421 is a horizontal electrode provided on the third electrode 43 side of the second electrode 42 so as to sandwich each electron beam from above and below in the vertical direction. Is a vertical electrode provided so as to sandwich each electron beam in the horizontal direction on the second electrode 42 side.

The horizontal electrode 411 and the vertical electrode 422 constitute the second electrostatic quadrupole lens 9, and the horizontal electrode 421 and the vertical electrode 432 constitute the first electrostatic quadrupole lens 9.

Further, between the third electrode 43 and the fourth electrode 44, there is provided a lens having a strong focusing force for focusing in both the horizontal and vertical directions. A lens is formed.

Further, as described with reference to FIG.
The first electrode 41 and the third electrode 43 constituting a kind of focusing electrode group
A constant first focusing voltage Vf1 is applied to the second electrode 42 and the fourth electrode 44 constituting the second type focusing electrode group. Dynamic voltage dVf that fluctuates in synchronization with the change
Is added to the second focusing voltage (Vf2 + dVf) as (Vf1)
> (Vf2 + dVf).

The second electrostatic quadrupole lens 9 provided between the first electrode 41 and the second electrode 42, the second electrode 42 and the third electrode 4
In the lens structure of the first electrostatic quadrupole lens 8 provided between the three, the portion where the flat horizontal electrode and the flat vertical electrode overlap forms a quadrupole lens. A very strong quadrupole lens can be formed by increasing the distance of the overlapping portion, and a weaker quadrupole lens can be formed by decreasing the distance of the overlapping portion.

Accordingly, a quadrupole lens provided between the first electrode 41 and the second electrode 42 as a lens for shaping the electron beam incident on the main lens can have a very strong electron beam shaping action. And a good and uniform focus can be obtained over the entire screen.

FIG. 3 is a perspective view illustrating a specific example of the structure of the second electrostatic quadrupole lens constituting the electron gun used in one embodiment of the color cathode ray tube of the present invention. The same reference numerals as 2 correspond to the same functional parts.

In this configuration example, the horizontal electrode 411 is provided with an independent U-shaped member for each electron beam on the surface of the first electrode 41 facing the second electrode 42, and the vertical electrode 422 is also provided for each electron beam. An independent U-shaped member is arranged on the surface of the second electrode 42 facing the first electrode 41 so as to surround the electron beam so that the overlap distance with the horizontal electrode 411 is increased.

As a result, a strong electrostatic quadrupole lens as described above can be formed. FIG. 4 is a front view of a second electrostatic quadrupole lens part constituting another embodiment of the electron gun used in the color cathode ray tube according to the present invention.
It is a front view of the part corresponding to. FIG. 5 is a perspective view illustrating a specific structure example of a second electrostatic quadrupole lens constituting an electron gun used in another embodiment of the color cathode ray tube of the present invention. 3 corresponds to FIG.

In this embodiment, a pair of flat plate-like horizontal electrodes 413 are arranged on the second electrode 42 side of the first electrode 41 so as to sandwich an electron beam passage hole from the direction perpendicular to the arrangement direction of the electron beams. A vertical electrode 423 made of a U-shaped member independent for each electron beam is surrounded by the electron beam so that the overlap distance between the horizontal electrode 411 and the surface of the second electrode 42 facing the first electrode 41 is increased. It is arranged.

Therefore, similarly to the above-described embodiment, the first electrode 4 is used as a lens for shaping the electron beam incident on the main lens.
A very powerful electron beam shaping action can be given to the quadrupole lens provided between the first and second electrodes 42,
Good and uniform focus can be obtained over the entire screen.

The configuration of the first electrostatic quadrupole lens 8 is also substantially the same as that of the second electrostatic quadrupole lens 9 described above, and the description of the configuration will be omitted.

The vertical electrodes 422 constituting the second electrostatic quadrupole lens are not only provided with a U-shaped member for each electron beam as in each of the above embodiments, but also in an in-line arrangement direction. It is also possible to adopt a configuration in which the U-shaped members are provided only for the electron beams at both ends.

FIG. 6 is a sectional view taken along a tube axis for explaining the overall structure of a color cathode ray tube according to the present invention. Numeral 31 denotes a panel portion constituting a screen, 32 denotes a neck portion for accommodating an electron gun, 33 Is a funnel part connecting the panel part and the neck part, 34 is a fluorescent film applied and formed on the inner surface of the panel part,
35 is a shadow mask which is a color selection electrode, 36 is a mask frame holding the shadow mask, 37 is a magnetic shield for shielding an external magnetic field, 38 is a shadow mask suspension spring, 39 is an electron gun according to the present invention, 40 is a deflection yoke, 41 is a magnet for correcting centering and prettyness, and B is an in-line arranged three electron beam.

This color cathode ray tube has a fluorescent film 34 on its inner surface.
A vacuum envelope is composed of a panel section 31 having a screen 31 formed by applying a coating, a neck section 32 containing an electron gun 39, and a funnel section 33 provided with a deflection yoke.

The electron gun 39 housed in the neck 32 is
It has the configuration described in the above embodiment, and has 3
The electron beam B is emitted toward the screen.

The deflection yoke 40 provided in the transition region between the funnel portion 33 and the neck portion 32 forms a deflection magnetic field for deflecting the three electron beams B emitted from the electron gun 39 in two directions, horizontal and vertical. The mask 35 is welded to the mask frame 36, and a suspension spring 38 fixed to a part of the outer periphery of the mask frame 36 is engaged with a panel pin erected on the inner wall of the panel portion, and is held at a predetermined interval from the fluorescent film 34. You.

According to this color cathode ray tube, a high-resolution image can be obtained over the entire screen.

The present invention is not limited to the above-described embodiment, but may be applied to electron guns of other types other than those described above, color cathode ray tubes having the electron guns, and other cathode ray tubes. It goes without saying that you can do it.

[0037]

As described above, according to the present invention,
An electrode means composed of a plurality of electrodes for focusing / accelerating an electron beam generated by a first electrode means, which is a three-pole part, and emitting the electron beam onto a screen is provided by a first kind of focusing electrode group and a second kind of focusing electrode group By forming focusing electrodes and forming at least two electrostatic quadrupole lenses between these electrode groups, correction of astigmatism due to deflection of an electron beam and correction of field curvature are performed independently. And the cross-sectional shape of the electron beam can be shaped freely, improving the correction sensitivity,
Astigmatism and curvature of field can be efficiently corrected regardless of the screen position, and a high-resolution color cathode ray tube having good focus over the entire screen can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view along an axial direction of a tube for explaining an embodiment of an in-line type three-beam electron gun used for a color cathode ray tube according to the present invention.

FIG. 2 is a front view of a second electrostatic quadrupole lens portion viewed from a direction AA in FIG. 1;

FIG. 3 is a perspective view illustrating a specific structure example of a second electrostatic quadrupole lens constituting an electron gun used in one embodiment of the color cathode ray tube of the present invention.

FIG. 4 is a front view of a second electrostatic quadrupole lens part constituting another embodiment of the electron gun used in the color cathode ray tube according to the present invention.

FIG. 5 is a perspective view illustrating a specific structure example of a second electrostatic quadrupole lens constituting an electron gun used in another embodiment of the color cathode ray tube of the present invention.

FIG. 6 is a cross-sectional view along the tube axis for explaining the overall structure of the color cathode ray tube according to the present invention.

FIG. 7 is a schematic sectional view, taken along a tube axis, for explaining a configuration of an electron gun used in a conventional high-resolution color cathode ray tube.

8 is a waveform diagram of a focusing voltage applied to the electron gun shown in FIG.

FIG. 9 illustrates a first electrode and a second electrode illustrating an example of the shape of a focusing electrode.
It is a schematic diagram of an electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cathode 2 Control electrode 3 Acceleration electrode 4 Focusing electrode 41 1st electrode 42 2nd electrode 43 3rd electrode 44 4th electrode 411 Horizontal electrode of 2nd electrostatic quadrupole lens 422 Vertical of 2nd electrostatic quadrupole lens Electrode 421 Horizontal electrode of first electrostatic quadrupole lens 432 Vertical electrode of first electrostatic quadrupole lens 5 Anode electrode 6 Shield cup.

Claims (1)

[Claims] 1. An electron beam generator for generating three electron beams arranged and controlled in a horizontal direction, and a main lens for converging three electron beams generated by the electron beam generator on a phosphor screen. A color cathode-ray tube having at least a deflection yoke for scanning the three electron beams on the phosphor screen, wherein the main lens portion of the electron gun has an anode to which an anode voltage is applied. A first type of focusing electrode group to which a first focusing voltage is applied, and a second type of focusing electrode group to which a second focusing voltage is applied. The second type of focusing electrode group is provided on the anode. And a dynamic voltage that changes in accordance with the amount of deflection of the electron beam is superimposed on a constant voltage of the second focusing voltage, and the first type focusing electrode group and the second type focusing electrode Between the electrode groups, the first Of the three electron beams in the horizontal and vertical directions together with an increase in the potential difference between the first focusing voltage applied to the focusing electrode group and the second focusing voltage applied to the second type focusing electrode group. At least one field curvature lens that has a strong focusing power for focusing in both directions is provided, and the focusing power for focusing the three electron beams in one of a horizontal direction and a vertical direction is increased, and further diverges to the other one. And at least two electrostatic quadrupole lenses having a strong diverging force are formed. Of the electrostatic quadrupole lenses, diverge in the horizontal direction with respect to the traveling direction of the electron beam and converge in the vertical direction. A first electrostatic quadrupole lens acting on the main surface and a second electrostatic quadrupole lens acting on the electron beam so as to converge in the horizontal direction and diverge in the vertical direction. Lens and first electrostatic A quadrupole lens and a second electrostatic quadrupole lens are sequentially arranged from the main lens side, and the second electrostatic quadrupole lens applies each electron beam to an electrode belonging to a first type of focusing electrode group. A collar comprising at least one pair of horizontal electrode pieces sandwiched from above and below in the vertical direction, and at least one pair of vertical electrode pieces sandwiching each electron beam from both sides in the horizontal direction to the electrodes belonging to the second type of focused electrode group. Cathode ray tube.