JP2000195435A - Color cathode ray tube having inline type electron gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode ray tube capable of displaying a high quality image by suppressing a change of a cut-off voltage of an electron gun caused by a change of a second focusing voltage varying in synchronization with a change of a deflection angle, and capable of securing good and uniform focus on a whole screen. SOLUTION: When an electrostatic quadrupole lens for reshaping a beam is formed by dividing a third electrode 4 into a third focusing electrode 41 of a first kind and a third focusing electrode 42 of a second kind, an electrode adjacent to a fourth electrode 5 is a third focusing electrode 42 for applying a second focusing voltage varying in synchronization with a change of a deflection angle for scanning an electron beam on a screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to a color cathode ray tube having an in-line type electron gun configured to emit three electron beams in a horizontal in-line toward a phosphor screen. .

[0002]

2. Description of the Related Art A color cathode ray tube used as a television picture tube or a monitor tube of an information terminal has a built-in electron gun for emitting a plurality (generally three) of electron beams in one end of a vacuum envelope. A phosphor screen having a plurality of colors (same as above, three colors) coated on the inner surface at the other end and a shadow mask which is a color selection electrode disposed close to the phosphor screen are built in, and are emitted from the electron gun. A required image is displayed on a screen (phosphor screen, screen screen, hereinafter simply referred to as screen) by two-dimensionally scanning a plurality of electron beams with a magnetic field generated by a deflection yoke installed outside the vacuum envelope. The so-called shadow mask type has become mainstream.

FIG. 5 is a schematic sectional view cut in the in-line direction for explaining the electrode configuration of an in-line type electron gun mounted on a conventional color cathode ray tube disclosed in Japanese Patent Application Laid-Open No. 4-43532. Is a cathode, 2 is a first electrode that is a control electrode, 3 is a second electrode that is an acceleration electrode, 4 is a third electrode, 5 is a fourth electrode, 6 is a fifth electrode, 7 is an anode, and 8 is a shield cup. is there.

The fifth electrode 6 is composed of a first type fifth electrode 61 and a second type
A fifth stage electrode 62 is composed of the third electrode 4, the fourth electrode 5, and the first type fifth electrode 61. The second stage fifth electrode 62 and the anode 7 form a front stage focusing lens. Form a focusing lens.

[0005] Between the first type fifth electrode 61 and the second type fifth electrode 62, a plate-shaped electrode 610 provided inside the first type fifth electrode 61 and the second type fifth electrode 61 are disposed. An electrostatic quadrupole lens is formed by the horizontal plate 621 erected on the surface of the five electrodes 62 facing the first type fifth electrode 61. Reference numeral 622 denotes a plate-shaped correction electrode provided inside the second type fifth electrode 62, and reference numeral 71 denotes a plate-shaped correction electrode provided inside the anode 7.

[0006] Thermions emitted from the heated cathode 1 constituting the electron beam generating means are controlled by the accelerating electrode potential applied to the first electrode 2 to the second electrode 3 serving as a control electrode.
The electron beam is accelerated to the side to form three electron beams arranged in a horizontal in-line.

The three electron beams emitted from the electron beam passage holes of the second electrode 3 serving as control electrodes are formed between the third electrode 4, the fourth electrode 5, and the first type fifth electrode 61. Of the second type fifth electrode 62
Before being incident on the main lens formed between the anode and the anode 7, each of the three electron beams is focused by the main lens formed between the second type fifth electrode 62 and the anode 7. Then, a focus is formed on the phosphor screen, and a beam spot is formed on the phosphor screen (screen).

A constant voltage (Vf1) is applied to the first type fifth electrode 61, and the second type fifth electrode 62 is synchronized with a change in the deflection angle at which the electron beam scans on the screen. And a dynamic voltage (Vd1) that fluctuates.

With this configuration, the field curvature is corrected by changing the intensity of the main lens according to the deflection angle of the electron beam.
Astigmatism is corrected by an electrostatic quadrupole lens composed of a plate-shaped electrode 610 and a horizontal plate 621 provided between the fifth kind of electrode 61 and the second kind of fifth electrode 62, and the electron beam By controlling the focus distance and the beam spot shape, it is possible to obtain good focus on the phosphor screen.

Furthermore, in order to obtain high resolution with better focus over the entire area on the phosphor screen, it is necessary to appropriately control the cross-sectional shape of the electron beam in accordance with the amount of deflection. There is.

In the electron gun configured as described above, the shape of the electron beam incident on the main lens becomes vertically long in synchronization with the increase in the amount of deflection of the electron beam by the electrostatic quadrupole lens for astigmatism correction. Since the electron beam is greatly affected by the deflection aberration that occurs when the electron beam passes through the formed deflection magnetic field, the electron beam has a horizontally elongated electron beam spot shape around the phosphor screen.

Therefore, in addition to the electrostatic quadrupole lens, the converging force for converging the electron beam in a direction opposite to the direction in which the electrostatic quadrupole lens converges the electron beam is increased, and the converging force in the other direction is increased. It is necessary to provide an electrostatic quadrupole lens for strengthening the diverging force as a beam shaping lens closer to the cathode than the electrostatic quadrupole lens, and to control the cross-sectional shape of the electron beam according to the magnitude of the deflection amount. There is.

When the fifth electrode 6 is further divided to form the electrostatic quadrupole lens for beam shaping, the strength of the electrostatic quadrupole lens can be increased due to restrictions on the electrode length of the fifth electrode. There is a limit.

Therefore, by dividing the third electrode, which is larger in distance from the main lens than the fifth electrode, into the first type of third focusing electrode group and the second type of third focusing electrode group, a strong beam is obtained. A shaping electrostatic quadrupole lens is formed. By this beam-shaping electrostatic quadrupole lens, the electrostatic quadrupole lens for correcting astigmatism cancels the action of elongating the electron beam as the deflection amount of the electron beam increases,
Good and uniform focus can be obtained over the entire screen.

[0015]

The third electrode is divided into the first type of third focusing electrode group and the second type of third focusing electrode group to form an electrostatic quadrupole lens for beam shaping. If
In order to achieve good resolution by achieving good focus over the entire screen, it is necessary to further enhance the electron beam shaping action.

Furthermore, a second focusing voltage that fluctuates in synchronization with a change in the deflection angle for scanning the electron beam on the screen is applied to the third focusing electrode group closer to the cathode that generates the electron beam than the fifth electrode. The second electrode
The change in the focusing voltage affects the cathode, the control electrode, and the acceleration electrode, and there is a problem that the cutoff voltage of the electron gun changes in synchronization with the change in the deflection angle at which the electron beam scans on the screen.

An object of the present invention is to solve the above-mentioned problems of the prior art, achieve a good and uniform focus over the entire screen, and change the second characteristic which fluctuates in synchronization with the change of the deflection angle.
An object of the present invention is to provide a color cathode ray tube capable of suppressing a change in a cut-off voltage of an electron gun due to a change in a focusing voltage and displaying a high-quality image.

[0018]

In order to achieve the above object, the present invention relates to a third electrode of an electron gun of the type described with reference to FIG. When forming the electrostatic quadrupole lens for beam shaping by dividing into three focusing electrodes, the electrode adjacent to the fourth electrode fluctuates in synchronization with the change in the deflection angle at which the electron beam is scanned on the screen. 2
This is achieved by using a second type of third focusing electrode to which a focusing voltage is applied.

A typical configuration of the present invention is described as follows. (1) having a cathode arranged in a horizontal in-line to generate three electron beams, an electron beam generating means including a control electrode and an accelerating electrode, and an electron beam focusing means including a focusing electrode and an anode; The focusing electrode includes a third electrode, a fourth electrode, and a fifth electrode that form a first-stage focusing lens, an in-line electron gun having a fifth electrode that forms a second-stage focusing lens with the anode, and the three electron beams. A cathode ray tube having at least a deflection yoke for scanning on a phosphor screen, wherein the third electrode of the electron gun comprises a first type of third focusing electrode to which a first focusing voltage is applied, and a second type of focusing electrode. A second type of third focusing electrode to which the first focusing voltage is applied, wherein the fifth electrode of the electron gun is a first type of fifth focusing electrode to which the first focusing voltage is applied; The second focusing voltage is applied An electrode belonging to the second type of focusing electrode group is adjacent to the anode, and the second focusing voltage is a dynamic voltage that changes to a constant voltage according to the amount of deflection of the electron beam. Are superimposed, and between the first type fifth focusing electrode and the second type fifth focusing electrode of the fifth electrode,
As the potential difference between the first focusing voltage and the second focusing voltage increases, the focusing force for focusing the three electron beams in one of the horizontal direction and the vertical direction increases, and the other one increases. At least one electrostatic quadrupole lens having a strong diverging force is formed between the first type third focusing electrode and the second type third focusing electrode. As the potential difference from the second focusing voltage increases, the focusing force for focusing the three electron beams in one of the horizontal and vertical directions increases, and the diverging force diverging in the other direction also increases. At least one strong electrostatic quadrupole lens is formed, and among the electrodes forming the electrostatic quadrupole lens in the third electrode, a dynamic voltage that changes according to the amount of deflection of the electron beam to a constant voltage. Voltage is superimposed The electrodes belonging to the second type of third focusing electrode second focusing voltage is applied and adjacent to the fourth electrode.

(2) An increase in the potential difference between the first focusing voltage and the second focusing voltage between the first type fifth focusing electrode and the second type fifth focusing electrode in (1). With
In addition to at least one electrostatic quadrupole lens, the convergence force for converging the three electron beams in one of the horizontal direction and the vertical direction is increased, and the divergence force diverging to the other is increased. And at least one field curvature lens having a strong focusing power for focusing the three electron beams in both the horizontal and vertical directions, wherein the first focusing voltage is higher than the second focusing voltage. In some cases, the electrostatic quadrupole lens in the third electrode of the electrostatic quadrupole lens 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. The electrostatic quadrupole lens disposed closest to the anode side in the group was diverged in the horizontal direction and focused in the vertical direction with respect to the traveling direction of the electron beam.

The present invention is not limited to the above configuration, and various deflections can be made without departing from the technical idea of the present invention.

[0022]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view of an electron gun for explaining an embodiment of a color cathode ray tube according to the present invention, and shows a horizontal section cut in an in-line direction.

As in the electron gun shown in FIG. 5, an electron beam generating means is composed of a cathode 1, a first electrode 2 as a control electrode, and a second electrode 3 as an acceleration electrode.

The third electrode 4 is composed of a first type third electrode 41 and a second type
And a fourth electrode 5 and a fifth electrode 6
And the anode 7 constitute an acceleration focusing means.

The fifth electrode 6 is composed of a first type fifth electrode 61 and a second type fifth electrode 62 sequentially arranged from the cathode 1 side to the anode 7 side.
And a third type of fifth electrode 63, and between the second type of fifth electrode 62 and the third type of fifth electrode 63, the electron beam is focused in both the horizontal direction and the vertical direction. A lens that increases the power is formed.

Between the first type fifth electrode 61 and the second type fifth electrode 62, the electron beam is diverged in the horizontal direction with an increase in the potential difference between the first focusing voltage and the second focusing voltage, In the vertical direction, there is provided an electrostatic quadrupole lens that acts to converge.

FIG. 2 is an explanatory diagram of the electrode configuration of the electrostatic quadrupole lens formed between the first type fifth electrode and the second type fifth electrode.

This electrostatic quadrupole lens is composed of a horizontal plate 611 erected on the second type fifth electrode 62 side of the first type fifth electrode 61.
a, 611 b and the first type fifth electrode 62 of the second type fifth electrode 62.
Vertical plates 621a, 621b, 62 planted on the electrode 61 side
1c and 621d.

Further, between the first type third electrode 41 and the second type third electrode 42, the horizontal focusing is performed with an increase in the potential difference between the first focusing voltage and the second focusing voltage. An electrostatic quadrupole lens for beam shaping that acts to diverge in the vertical direction is provided.

This electrostatic quadrupole lens for beam shaping is
The vertical plate 411 planted on the second type third electrode 42 side of the first type third electrode 41 and the horizontal plate planted on the first type third electrode 41 side of the second type third electrode 42 421. The configurations of the vertical plate and the horizontal plate are the same as those shown in FIG.

The first type third electrode 41 and the second type fifth electrode 62 are provided with a constant, that is, a DC first focusing voltage (Vf).
1) is applied, and the second type third electrode 42, the first type fifth electrode 61 and the third type fifth electrode 63 apply an electron beam on the screen to a constant, that is, a DC voltage (Vf2). A second focusing voltage (Vf2 + dV) to which a dynamic voltage (dVf) that fluctuates in synchronization with a change in the scanning deflection angle is added.
f) is applied.

[0033] The two DC focusing voltages Vf1 and Vf2 are obtained by dividing the first focusing voltage (Vf1)> the second focusing voltage (Vf1).
2 + dVf). FIG. 3 shows the first focusing voltage (Vf1) and the second focusing voltage (Vf2 + dVf).
Shows the size and waveform.

When the focusing voltage is applied to the electron gun, the lens formed between the second-type fifth electrode 62 and the third-type fifth electrode 63 has a dynamic voltage at which the deflection amount of the electron beam increases. When increasing, the fifth electrode 62 of the second type and the third electrode
The potential difference between the seed fifth electrodes 63 is reduced, and the focusing power for focusing in both the horizontal direction and the vertical direction is weakened, so that the field curvature is corrected during electron beam deflection.

According to this configuration, in addition to the conventional field curvature correction lens formed between the second type fifth electrode 62 and the anode 7 shown in FIG. Since the field curvature correction lens is also formed between the fifth type of electrode 62 and the third type of fifth electrode 63, a good focus can always be obtained on the screen with a smaller dynamic voltage than in the related art.

Also, at the center of the screen where the potential difference between the first focusing voltage and the second focusing voltage is maximum, the divergence and vertical divergence between the first type fifth electrode 61 and the second type fifth electrode 62 in the horizontal direction. The cross section of the electron beam is affected by the electrostatic quadrupole lens acting to converge in the direction.

The first kind of third electrode 41 and the second kind of third electrode 41 having the opposite action to the electrostatic quadrupole lens between the first kind of fifth electrode 61 and the second kind of fifth electrode. In an electrostatic quadrupole lens that acts so as to converge the horizontal direction formed between them and diverge in the vertical direction, the cross-sectional shape of the electron beam is vertically elongated.

At this time, the second type of third electrode 42 adjacent to the fourth electrode 5 among the electrodes constituting the third electrode 4 is synchronized with a change in the deflection angle at which the electron beam scans on the screen. And applying the second focusing voltage that varies.

By applying the second focusing voltage to the second type third electrode 42 adjacent to the fourth electrode 5, the electron beam is applied between the second type third electrode 42 and the fourth electrode 5. Is formed on the screen to change the intensity in synchronization with the change in the deflection angle. The electrostatic quadrupole lens between the third electrode 42 and the fourth electrode 5 of the second type is connected to the third electrode 41 of the first type and the second
It has the same beam shaping action as an electrostatic quadrupole lens between the third electrodes 42 of the kind.

Therefore, the first type third electrode 41 and the second type
In addition to the electrostatic quadrupole lens between the third electrodes 42 of the species, the electrostatic quadrupole between the third electrodes 42 and the fourth electrodes 5 of the second kind, to which the second focusing voltage is applied, adjacent to the fourth electrode 5. By forming the quadrupole lens, the electron beam shaping action can be strengthened, the lateral length of the electron beam cross-sectional shape due to deflection aberration can be suppressed, and good and uniform focus can be obtained over the entire screen.

Further, since the second type third electrode 42 for applying the second focusing voltage which fluctuates in synchronization with the change of the deflection angle for scanning the electron beam on the screen is adjacent to the fourth electrode 5, the cathode 1 , The distance from the control electrode (first electrode) 2 and the acceleration electrode (second electrode) 3 is suppressed, so that the cut-off voltage of the electron gun is not changed according to the change of the dynamic voltage, and the deterioration of image quality is prevented. It is possible to do.

FIG. 4 is a cross-sectional view for explaining an example of the structure of a color cathode ray tube according to the present invention, in which 11 is a panel portion constituting a screen screen, 12 is a neck portion for accommodating an electron gun,
13 is a funnel part connecting the panel part and the neck part,
14 is a phosphor screen (phosphor screen), 15 is a shadow mask which is a color selection electrode, 16 is a mask frame for supporting the shadow mask, 17 is a magnetic shield for shielding terrestrial magnetism, 18 is a mask suspension mechanism, 19 is an in-line type An electron gun, 20 is a deflection yoke, 21 is a correction magnetic device, 22 is a stem pin, and 23 is a getter.

In this color cathode ray tube, the panel section 11, the neck section 12, and the funnel section 13 constitute a vacuum envelope, and the electron gun 19 housed inside the neck section 12 has the above-mentioned electrode structure. The electron beam B (center beam, side beam × 2) emitted from the electron gun 19 scans the fluorescent screen 14 two-dimensionally by the horizontal and vertical deflection magnetic fields formed by the deflection yoke 20.

The electron beam B is intensity-modulated by a modulation signal such as a video signal supplied from the stem pin 22, and
The color is selected by the shadow mask 15 placed just before the target and collides with each phosphor to reproduce a predetermined color image.

With this color cathode ray tube, it is possible to obtain a good focus on the electron beam formed on the phosphor screen over the entire area of the screen screen and to obtain a high quality color image by suppressing a change in cutoff voltage. it can.

[0046]

As described above, according to the present invention,
The third electrode of the electron gun accommodated in the neck is formed by a first type of third focusing electrode group to which a first focusing voltage is applied, and a second type of third focusing electrode to which a second focusing voltage is applied. By dividing the electrode into a group and making the electrode adjacent to the fourth electrode a second type of third focusing electrode to which a second focusing voltage is applied, a second type of third focusing electrode adjacent to the fourth electrode can be formed. Between the fourth electrodes, an electrostatic quadrupole lens whose intensity changes in synchronization with a change in the deflection angle at which the electron beam scans on the screen is formed, and the first type third focusing electrode group and the second type An electron beam shaping function similar to that of the beam shaping electrostatic quadrupole lens formed by being divided into the third focusing electrode group is given to the electron beam with a change in the dynamic voltage, so that the beam shaping action can be enhanced. Good and uniform focus can be obtained over the entire screen.

Further, the second type of third focusing electrode to which the second focusing voltage is applied is moved away from the cathode, the control electrode and the accelerating electrode constituting the electron gun, and the deflection angle for scanning the electron beam on the screen is changed. The change of the cut-off voltage of the electron gun due to the change of the second focusing voltage which fluctuates in synchronism with the above can be suppressed, and a high quality color image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an electron gun illustrating an embodiment of a color cathode ray tube according to the present invention, which is a horizontal cross section cut in an inline direction.

FIG. 2 is an explanatory diagram of an electrode configuration of an electrostatic quadrupole lens formed between a first type fifth electrode and a second type fifth electrode in FIG. 1;

FIG. 3 is a waveform diagram of a focusing voltage applied to the electron gun of the present invention.

FIG. 4 is a cross-sectional view illustrating a structural example of a color cathode ray tube according to the present invention.

FIG. 5 is a schematic sectional view cut in an in-line direction for explaining an electrode configuration of an in-line type electron gun mounted on a conventional color cathode ray tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cathode 2 Control electrode (1st electrode) 3 Acceleration electrode (2nd electrode) 4 3rd electrode 41 1st-type 3rd electrode 42 2nd-type 3rd electrode 5 4th electrode 6 5th electrode 61 1st-type Fifth electrode 62 Second type fifth electrode 63 Third type fifth electrode 7 Anode 8 Shield cup.

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[Procedure amendment]

[Submission date] August 3, 1999 (1999.8.3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

The fifth electrode 6 is composed of a first type fifth electrode 61 and a second type fifth electrode 62 sequentially arranged from the cathode 1 side to the anode 7 side.
And a third type of fifth electrode 63, and between the second type of fifth electrode 62 and the third type of fifth electrode 63, the electron beam is focused in both the horizontal direction and the vertical direction. A lens that increases the power is formed. Note that reference numeral 631 is the first
A plate-shaped correction electrode installed inside the three kinds of fifth electrodes 63
is there.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

This electrostatic quadrupole lens for beam shaping is
A horizontal plate 411 planted on the second type third electrode 42 side of the first type third electrode 41 and a vertical plate planted on the first type third electrode 41 side of the second type third electrode 42 421. The configurations of the vertical plate and the horizontal plate are the same as those shown in FIG.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shinichi Kato 3300 Hayano, Mobara-shi, Chiba Pref.Electronic Device Division, Hitachi, Ltd. Inside F-term (reference) 5C041 AA03 AA12 AA14 AB07 AC26 AC35 AD02 AD03

Claims (2)

[Claims] An electron beam generating means comprising a control electrode and an accelerating electrode; and an electron beam focusing means comprising a focusing electrode and an anode. The focusing electrode includes a third electrode, a fourth electrode, and a fifth electrode that form a first-stage focusing lens, an in-line electron gun having a fifth electrode that forms a second-stage focusing lens with the anode, and the three electron beams. A cathode ray tube having at least a deflection yoke for scanning on a phosphor screen, wherein the third electrode of the electron gun comprises a first type of third focusing electrode to which a first focusing voltage is applied, and a second type of focusing electrode. A second type of third focusing electrode to which the first focusing voltage is applied; and a fifth type of focusing electrode to which the first focusing voltage is applied; and a second type of third focusing electrode to which the first focusing voltage is applied. Second type to which the focusing voltage of is applied A fifth focusing electrode, an electrode belonging to the second type of focusing electrode group is adjacent to the anode, and the second focusing voltage is a constant voltage on which a dynamic voltage that changes according to the amount of deflection of the electron beam is superimposed. Between the first type fifth focusing electrode and the second type fifth focusing electrode of the fifth electrode, as the potential difference between the first focusing voltage and the second focusing voltage increases, At least one electrostatic quadrupole lens is formed in which the converging force for converging the three electron beams in one of the horizontal direction and the vertical direction is increased, and the diverging force for the other is increased. The three electron beams are supplied between the first type of third focusing electrode and the second type of third focusing electrode together with an increase in the potential difference between the first focusing voltage and the second focusing voltage. Gather in either the horizontal or vertical direction At least one electrostatic quadrupole lens is formed, in which the converging power for bundling is increased and the diverging force for diverging in another direction is further increased, forming an electrostatic quadrupole lens in the third electrode. The electrodes belonging to a second type of third focusing electrode to which a second focusing voltage in which a dynamic voltage that varies in accordance with the amount of deflection of the electron beam is superimposed on a constant voltage are applied to the fourth electrode. A color cathode ray tube characterized by being adjacent. 2. The first type fifth focusing electrode and the second type fifth focusing electrode.
Between the focusing electrodes, as the potential difference between the first focusing voltage and the second focusing voltage increases, the focusing force for focusing the three electron beams in either the horizontal direction or the vertical direction increases. In addition to at least one electrostatic quadrupole lens, which has a stronger diverging force diverging to the other,
At least one curvature-of-field lens having a strong focusing power for focusing the three electron beams in both the horizontal direction and the vertical direction is provided, and the first focusing voltage is higher than the second focusing voltage. In this case, the electrostatic quadrupole lens in the third electrode of the electrostatic quadrupole lens 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. The electrostatic quadrupole lens located closest to the anode side diverges in the horizontal direction with respect to the traveling direction of the electron beam,
2. A color cathode ray tube according to claim 1, wherein said color cathode ray tube acts to focus in a vertical direction.