JPH09306380A - Cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode ray tube provided with an electron gun capable of obtaining a good picture quality even in a screen peripheral part, by performing a dynamic focus with one kind of focusing voltage. SOLUTION: An electron lens is formed between a focusing electrode 5 and a fourth electrode 4 adjacent to the focusing electrode to apply relatively low voltage as compared with voltage applied to the focusing electrode, and the electron lens, giving focusing action in a parallel direction stronger than in a right angle direction to an in-line direction relating to an electron beam, is formed, and focusing voltage, increased to be matched with increasing of a deflecting amount of the electron beam, is applied to the focusing electrode 5.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a cathode ray tube,
In particular, changing the cross-sectional shape of the electron beam according to the deflection amount,
The present invention relates to a high-definition cathode ray tube using an electron gun that reduces astigmatism and field curvature due to a deflection magnetic field.

[0002]

2. Description of the Related Art An electron gun used for a cathode ray tube such as a television picture tube or a display tube has a screen of a cathode ray tube in order to obtain a high resolution with good focus characteristics on the screen. It is necessary to properly control the spot shape of the electron beam in accordance with the amount of deflection.

A cathode ray tube using this type of electron gun is disclosed in, for example, JP-A-2-72546 or JP-A-7-161309.

FIG. 9 is a schematic cross-sectional view taken along the tube axis for explaining a configuration example of the conventional electron gun for a cathode ray tube disclosed in the above publication, in which K is a cathode, 1 is a first electrode, and 2 is a second electrode. An electrode, 3 is a third electrode, 4 is a fourth electrode (focusing electrode) including the first divided electrode 41 and the second divided electrode 42, 5 is a fifth electrode, 6 is a 6th electrode, and 7 is a shield cup. .

Reference numeral 4-1 is a vertical correction plate (horizontal plate electrode) provided on the side of the second divided electrode 42 of the first divided electrode 41, 4
Reference numeral -2 is a horizontal correction plate (vertical plate electrode) provided on the first divided electrode 41 side of the second divided electrode 42, and constitutes a so-called electrostatic quadrupole. 51 and 61 are the fifth electrode 5 and the sixth electrode, respectively.
It is an astigmatism correction electrode plate installed inside the electrode 6.

FIG. 10 is a perspective view for further explaining the electrode configuration of the electrostatic quadrupole in FIG. 9, and the same reference numerals as those in FIG. 9 correspond to the same parts.

In FIGS. 9 and 10, the fifth electrode 5 is a low voltage side electrode, the sixth electrode 6 is a high voltage side electrode, and a main lens is formed at the portion where the fifth electrode 5 and the sixth electrode 6 face each other. It

Astigmatism correction electrode plates 51 and 6 are provided inside the fifth electrode 5 and the sixth electrode 6 forming the main lens, respectively.
1 is installed.

In this type of electron gun, the electrostatic portion 4 for correcting the deflection aberration is provided at the facing portion of the first divided electrode 41 and the second divided electrode 42 which constitute the focusing electrode 4 which is the fourth electrode.
A dipole lens is installed.

This electrostatic quadrupole lens is shown in FIG.
As shown in (b), a pair of vertical correction plates 4-1 provided on the opposite side of the first divided electrode 41 constituting the focusing electrode 4 which is the fourth electrode from the second divided electrode 42, and FIG. ), It is composed of two pairs of horizontal correction plates 4-2 provided on the opposite side of the second divided electrode 42 to the first divided electrode 41,
It is arranged as shown in FIG.

The vertical correction plate 4-1 is composed of a pair of substantially rectangular plate bodies installed so as to sandwich the electron beam passage opening of the first divided electrode 41 from the vertical direction, and the horizontal correction plate 4 is also provided.
Reference numeral -2 is composed of a plurality of substantially rectangular plate bodies installed so as to sandwich each of the three electron beam passage openings formed in the second divided electrode 42 from the horizontal direction.

Then, a fixed focus voltage Vf ₁ is applied to the third electrode 3 and the second divided electrode 42, and the second divided electrode 41
And a voltage (V which is obtained by superimposing a fixed voltage Vf ₂ on the fifth electrode 5 with an alternating voltage dVf which changes in synchronization with the deflection amount of the electron beam.
f ₂ + dVf) is applied. As described above, in the related art, the focusing voltage is fixed to the constant voltage Vf ₁ applied to the third electrode 3 and the second divided electrode 42 and the constant voltage Vf ₂ applied to the second divided electrode 41 and the fifth electrode 5. Divided into dynamic voltage d
By superimposing Vf on Vf ₂ , field curvature and astigmatism associated with electron beam deflection are corrected.

At this time, the constant voltages Vf ₁ and Vf ₂ have substantially equal voltage values, and the dynamic voltage dVf is the electronic beam.
It has a waveform that increases as the amount of deflection of the diaphragm increases.

On the other hand, in the electron gun disclosed in Japanese Unexamined Patent Publication No. 7-161309, as shown in FIG. 11, the constant voltage Vf ₁ is set to a voltage value considerably larger than the constant voltage Vf ₂ , and the voltage difference between them is set. (Vf ₁ −Vf ₂ ) is at least d
It is set to be larger than the maximum value of Vf.

As a result, when the dynamic voltage dVf increases, that is, when the electron beam deflection amount is large, the potential difference in the field curvature correction lens becomes small and the lens strength decreases. Therefore, the force for focusing the electron beam becomes weak when the electron beam is deflected, and the field curvature is corrected.

With such an electrode structure and voltage application method, the dynamic voltage is reduced, and an increase in circuit cost and the like can be suppressed.

With the above structure, the cross-sectional shape of the electron beam at the time of focusing can be controlled, astigmatism can be corrected, and a high-resolution color cathode ray tube can be obtained.

[0018]

In the above prior art, the focusing electrode (fourth electrode 4) adjacent to the fifth electrode 5 constituting the accelerating electrode (main lens) is provided with the first split electrode 41 and the second electrode.
The split electrode 42 is formed, and a non-axisymmetric (that is, non-circular in cross section) electron lens is formed between the first split electrode 41 and the second split electrode 42, and is synchronized with the deflection of the electron beam. By applying a fluctuating voltage to the first divided electrode 41, the cross section of the electron beam is deformed to correct the astigmatism due to the deflection, and the lens strength of the main lens is changed in synchronization with the deflection of the electron beam. The field curvature at the periphery of the screen screen is corrected.

However, in the above structure, there are two kinds of voltages to be supplied to the focusing electrodes, and when applied to a cathode ray tube such as a television picture tube or a display tube, a special high voltage is supplied from the stem pin. There is a problem that conventional general-purpose parts cannot be used, such as a stem and a special socket for supplying voltage.

An object of the present invention is to provide a cathode ray tube equipped with an electron gun which can obtain a good image quality even in the peripheral portion of a screen screen by using a conventional stem and socket with one kind of voltage supplied to a focusing electrode. To do.

[0021]

In order to achieve the above object, a first invention according to claim 1 generates a plurality of electron beams, and these electron beams are parallel to each other on one horizontal plane. It has a first electrode means composed of a plurality of electrodes directed to the screen along the initial path, and a second electrode means composed of a plurality of electrodes forming a main lens for focusing the electron beam on the screen. In a cathode ray tube equipped with an electron gun, of the electrodes forming the second electrode means of the electron gun, a voltage relatively lower than a focusing electrode and a voltage applied to the focusing electrode adjacent to the focusing electrode. An electron lens formed between the electrode for applying and forming an electron lens that gives a stronger focusing action to the electron beam than the direction perpendicular to the one horizontal plane at a right angle, and And applying a voltage which increases in accordance with the increase in the amount of deflection of the child beam.

In a second aspect of the invention, of the electrodes forming the second electrode means of the first aspect of the invention, the acceleration electrode to which the highest voltage is applied is adjacent to the acceleration electrode. The electron lens formed by the focusing electrode is characterized by forming an electron lens that gives a stronger focusing action to the electron beam than a direction parallel to the one horizontal plane at right angles.

[0023]

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

FIG. 1 is a schematic diagram for explaining the structure of an electron gun included in a first embodiment of a cathode ray tube according to the present invention, in which 1 is a first electrode, 2 is a second electrode, and 3 is a third electrode. 4 is a 4th electrode, 5 is a 5th electrode, 6 is a 6th electrode, 7 is a shield cup, 4-1 is a vertical plate electrode (horizontal correction plate), 5-1
Is a horizontal plate electrode (vertical correction plate), 51 and 61 are astigmatism correction electrode plates, and K is a cathode. The figure is a cross section of the in-line type electron gun seen from the in-line arrangement direction.

In the figure, the cathode K and the first electrode 1 and the second electrode 2 constitute a first electrode means (so-called tripolar portion), and the third electrode 3, the fourth electrode 4 and the fifth electrode are formed. The fifth and sixth electrodes 6 form a second electrode means.

The first control voltage E is applied to the first electrode 1.
c1, a second control voltage Ec2 to the second electrode 4 and the fourth electrode 4 (hereinafter, also referred to as a focusing electrode), a third control voltage Ec2 to the third electrode 5
A voltage, which is a fixed focusing voltage Vf and a dynamic focusing voltage Vd superimposed on the deflection, is applied to the electrode 5, and an anode voltage (house voltage) Eb, which is the highest voltage, is applied to the sixth electrode 6, which is an accelerating electrode. It The second control voltage Ec2 is a voltage relatively lower than the focusing voltage Vd.

When the focusing voltage Vd which increases in synchronization with the increase in the deflection amount of the electron beam is applied to the focusing electrode 5 which is the focusing electrode, the quadrupole lens formed at the opposing portion of the focusing electrode 5 and the fourth electrode 4 The intensity is increased and the astigmatism due to the deflection of the electron beam is corrected.

At the same time, the acceleration voltage E applied to the acceleration electrode 6
Since the voltage difference between b and the voltage Vd applied to the focusing electrode 5 is reduced, the lens strength of the main lens is reduced and the distance between the main lens and the focal point of the electron beam is increased. The electron beam can be focused with high precision even in the peripheral portion of the screen.

Further, the main lens formed by the accelerating electrode 6 and the focusing electrode 5 is an electron lens having a stronger focusing action in the vertical direction than the horizontal direction with respect to the electron beam, so that the electron beam can be focused without deflection. Electrode 5 and fourth electrode 4
It is possible to cancel the action of the quadrupole lens, which has a stronger focusing action in the horizontal direction than in the vertical direction, which is formed at the facing portion, and to form a substantially circular electron beam spot in the central portion of the screen screen.

As a result, a high resolution image can be obtained over the entire screen screen.

FIG. 2 is a schematic cross-sectional view of the main structure for explaining the structure of the electron gun provided in the second embodiment of the cathode ray tube according to the present invention.

FIG. 3 is a sectional view of the main part of FIG.
2A is a sectional view taken along line AA of FIG. 2, and FIG. 3B is a sectional view taken along line BB of FIG.

FIG. 2 is a cross-sectional view of the main parts of the accelerating electrode 6 and the focusing electrode 5 constituting the bipotential type main lens, showing an example of the main lens having a stronger focusing action in the vertical direction than in the horizontal direction with respect to the electron beam. The electron beam passage holes 51a, 51b, 51c formed in the astigmatism correction electrode plate 51 installed inside the focusing electrode 5 and the astigmatism correction electrode plate 61 installed inside the acceleration electrode 6 are The formed electron beam passage holes 61a, 61b, 61c have an elliptical shape having a long axis in the vertical direction as shown in FIG. 3, and the electron beam passage holes facing each other have the same opening shape and size.

In this structure, the retreat amount d of the astigmatism correction electrode plate 51 from the surface of the focusing electrode 5 facing the acceleration electrode 6 side.
1, the receding amount d2 of the astigmatism correction electrode plate 61 from the surface of the acceleration electrode 6 facing the focusing electrode 5 side, the vertical diameter a1 of the electron beam passage holes 51a and 51c of the astigmatism correction electrode plate 51, the horizontal diameter a3, And the horizontal diameter a4 of the electron beam passage hole 51b and the electron beam passage holes 61a and 61 of the astigmatism correction electrode plate 61.
By selecting the vertical diameter b1 and horizontal diameter b3 of c, the vertical diameter b2 and horizontal diameter b4 of the electron beam passage hole 61b, and performing the same voltage as in the above embodiment, the vertical focusing action on the electron beam is obtained. Can be stronger than the focusing effect in the horizontal direction, and a high-resolution image can be obtained over the entire screen screen.

FIG. 4 is a schematic cross-sectional view of the structure of the main part for explaining the structure of the electron gun provided in the cathode ray tube according to the third embodiment of the present invention. A configuration example of a quadrupole lens having a strong focusing action is shown.

In the figure, the focusing electrode 5 has a fourth electrode 4
3 circular electron beam passage holes are provided on the surface opposite to and horizontal electrode plates (vertical plate electrodes) 5-1 extending in the fourth electrode 4 direction are arranged above and below the electron beam passage holes in the vertical direction. It The fourth electrode 4 has a single horizontally elongated hole portion having a long axis in the horizontal direction on the end surface facing the focusing electrode 5, and an electrode provided with three circular electron beam passage holes therein. A plate 41 is installed.

Also in this embodiment, similarly to the above embodiment, the focusing voltage Vd which increases in synchronization with the increase of the deflection amount of the electron beam is applied to the focusing electrode, and the fourth electrode is the same as the second electrode. A voltage lower than the focusing voltage Vd is applied.

With this configuration, the vertical focusing action on the electron beam can be made stronger than the horizontal focusing action, and a high-resolution image can be obtained over the entire screen screen.

FIG. 5 is a schematic cross-sectional view of the main structure for explaining the structure of the electron gun included in the fourth embodiment of the cathode ray tube according to the present invention. 6 is a front view of a main part of FIG. 5, (a) is a front view of the focusing electrode 5 viewed from the fourth electrode 4 side, and (b) is a front view of the fourth electrode 4 viewed from the focusing electrode 5 side. It is a figure.

In FIGS. 5 and 6, the focusing electrode 5 is provided with three laterally long holes 5a, 5b, 5c having a major axis in the horizontal direction on the end surface facing the fourth electrode 4, and the fourth electrode 4 is formed. In 4,
Three vertically elongated holes 4a, 4b, 4c having a long axis in the vertical direction are formed on the end surface facing the focusing electrode 5.

Also in this embodiment, similarly, the focusing voltage Vd which increases in synchronization with the increase of the deflection amount of the electron beam is applied to the focusing electrode, and the focusing voltage Vd is applied to the fourth electrode at the same voltage as the second electrode. By applying a relatively lower voltage, the vertical focusing effect on the electron beam can be made stronger than the horizontal focusing effect, and a high-resolution image can be obtained over the entire screen screen.

FIG. 7 is a side view for explaining the overall structure of the electron gun used in the cathode ray tube of the present invention, where 1 to 8 and K correspond to the same parts as in FIG. 1 and 8 is beading. Glass and 9 are stems.

This electron gun has an electrostatic quadrupole lens formed between the fourth electrode 4 and the focusing electrode 5 and has the electrode configuration and the power feeding configuration described in the embodiment of the diffuser plate. One type of focusing voltage is supplied through the same pin of the stem 9.

FIG. 8 is a cross-sectional view of a shadow mask type color cathode ray tube for explaining an example of the whole structure of the cathode ray tube according to the present invention. 31 is a panel portion forming a screen, and 32 is an electron gun. A neck portion, 33 is a funnel portion connecting the panel portion and the neck portion, 34 is a fluorescent screen,
35 is a shadow mask, 36 is a mask frame, 37 is a magnetic shield, 38 is a mask suspension mechanism, 39 is an electron gun,
Reference numeral 40 is a deflection yoke, and 41 is a magnetic adjustment magnet.

In the figure, the electron beam B emitted from the electron gun 39 housed in the neck 32 is deflected by the deflection yoke 4.
The entire area of the fluorescent screen 34 constituting the screen screen is scanned by the horizontal and vertical deflection magnetic fields formed by zero.

The electron beam B is composed of three electron beams corresponding to the red, green and blue phosphors, and the color is selected by the shadow mask 35 arranged immediately in front of the phosphor screen 34 to irradiate each phosphor. By hitting, a desired color image is reproduced.

The electron gun 39 has the structure described in the above embodiment, and can achieve high resolution over the entire screen screen.

[0048]

As described above, according to the present invention,
By supplying one type of voltage synchronized with the deflection of the electron beam to the focusing electrode, it is possible to simultaneously perform the astigmatism correction and the field curvature correction associated with the deflection of the electron beam, and the entire screen screen. Since a good beam spot can be obtained, it is possible to provide a cathode ray tube having an excellent image quality with high resolution.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the configuration of an electron gun included in a first embodiment of a cathode ray tube according to the present invention.

FIG. 2 is a schematic cross-sectional view of a main part structure for explaining a configuration of an electron gun included in a second embodiment of the cathode ray tube according to the present invention.

FIG. 3 is a cross-sectional view of relevant parts in FIG. 2 for explaining the configuration of an electron gun included in a second embodiment of the cathode ray tube according to the present invention.

FIG. 4 is a schematic cross-sectional view of a main part structure for explaining a configuration of an electron gun included in a third embodiment of the cathode ray tube according to the present invention.

FIG. 5 is a schematic cross-sectional view of a main part structure for explaining a configuration of an electron gun included in a fourth embodiment of the cathode ray tube according to the present invention.

FIG. 6 is a front view of relevant parts of FIG. 5 for explaining the configuration of an electron gun included in a fourth embodiment of a cathode ray tube according to the present invention.

FIG. 7 is a side view for explaining the overall configuration of an electron gun used in the cathode ray tube of the present invention.

FIG. 8 is a cross-sectional view of a shadow mask type color cathode ray tube for explaining an example of the entire configuration of the cathode ray tube according to the present invention.

FIG. 9 is a schematic cross-sectional view taken along the tube axis for explaining a configuration example of a conventional electron gun for a cathode ray tube.

FIG. 10 is a perspective view further explaining the electrode configuration of the electrostatic quadrupole in FIG.

FIG. 11 is an explanatory diagram of a focused voltage waveform.

[Explanation of symbols]

 1 1st electrode 2 2nd electrode 3 3rd electrode 4 4th electrode 5 5th electrode 6 6th electrode 7 Shield cup 4-1 Vertical flat plate electrode (horizontal correction plate) 5-1 Horizontal flat plate electrode (vertical correction plate) 51 , 61 Astigmatism correction electrode plate K cathode.

Claims (2)

[Claims] 1. A first electrode means comprising a plurality of electrodes for generating a plurality of electron beams and directing the electron beams to a screen along initial paths parallel to each other on one horizontal plane, and A cathode ray tube equipped with an electron gun having a second electrode means composed of a plurality of electrodes forming a main lens for focusing an electron beam on a screen, the electrode forming the second electrode means of the electron gun. Among them, an electron lens formed between the focusing electrode and an electrode that is adjacent to the focusing electrode and applies a relatively low voltage compared to the voltage applied to the focusing electrode is a horizontal plane with respect to the electron beam. It is characterized in that an electron lens that forms a stronger focusing action in a parallel direction than in a right direction is formed, and that a voltage that increases in accordance with an increase in the deflection amount of the electron beam is applied to the focusing electrode. Cathode ray tube. 2. An electron lens formed by an accelerating electrode to which the highest voltage is applied and a focusing electrode adjacent to the accelerating electrode, among the electrodes forming the second electrode means, A cathode ray tube, characterized by forming an electron lens which gives a stronger focusing action to a beam in a direction perpendicular to the one horizontal plane than in a direction parallel to the beam.