JPH0428149A - Cathode-ray tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to color cathode ray tubes such as television picture tubes and display tubes used in information processing terminals, and in particular to color cathode ray tubes that have high resolution and good convergence characteristics. Concerning a cathode ray tube equipped with a gun.

[Prior Art] As the screens of color television receivers become larger and the density of terminal displays becomes higher, improvements in the high-definition video/image display capability and low aberration characteristics of color cathode ray tubes are required.

As an electron gun that increases the definition in a multi-beam color cathode ray tube and achieves good convergence by eliminating aberrations, the main lens is a large-diameter electron lens that is common to multiple beams, as disclosed in Japanese Patent Publication No. 49-5591. It was adopted in A so-called single electron gun three-heem electron gun is known.

FIG. 6 is a schematic diagram illustrating the configuration of a single electron gun three-beam electron gun according to the prior art, in which 1 indicates the first pole (G,).
, 2 is the second electrode (G2), 3 is the third electrode (G,), 4
is the fourth electrode (G4), 5 is the fifth electrode (G, ), 61
．． 62 is an electrostatic deflection plate, 81, 82.83 are each red,
Cathodes (K, KG, Kl) are electron beam sources that emit green and blue electron beams, and 10 is a screen.

In the same figure, cathodes 81, 82, 83 are connected in the X-axis direction (
The horizontal deflection direction of the electron beam and the vertical deflection direction of the electron beam are the y-axis direction, and the screen 10 is perpendicular to the y-axis and the y-axis.
The first electrode 1 is arranged on a common plane (with the upward direction being the biaxial direction) and is common to these cathodes 81, 82, 83.
．． Second electrode2. Third electrode 3. 4th pole 4. The fifth poles 5 are arranged in this order in the screen direction.

A triode is formed by the cathodes 81, 82, 83, the first electrode 1, and the second electrode 2, and the third electrode 3. is a cylindrical electrode. 4th electrode 4 (focusing electrode), 5th electrode (acceleration electrode) 5
A unipotential main lens is formed by this.

In such a configuration, three electron beams (BR, BG, Bfl) emitted from the cathode 81.82.83
intersect approximately at the center of the main lens at a position that satisfies the Franchaux core condition (condition for comatic aberration to be zero).

Further, the three electron beams are deflected by electrostatic deflection plates 61 and 62 provided after the fifth electrode 5 so as to converge on the screen 10.

On the other hand, there is a so-called self-convergence deflection yoke in which the horizontal and vertical deflection coils are distorted so that the three electron beams are optimally converged even around the screen 10.

In a cathode ray tube using a self-convergence deflection yoke with the above distortion, the quadrupole magnetic field component generated due to the distortion causes astigmatism in the electron beam. That is, the electron beam is subjected to a focusing effect in the vertical direction and a diverging effect in the horizontal direction.

As a result, the beam pond on the screen surface has a shape as shown in FIG.

FIG. 7 is an explanatory diagram of spot distortion of the electron beam due to the self-convergence deflection yoke, and when the electron beam B passing through the deflection magnetic field obtains a circular spot at the center part Sc of the screen, the horizontal axis direction (X direction) The electron beam Hs in the peripheral portion becomes overfocused in the vertical direction, and a vertically long halo (overfocusing portion) HA is generated around the core CO, so that the electron beam spot becomes substantially large.

This is because the horizontal deflection coil is shaped like a saddle, and the generated magnetic field has a vincsion type magnetic field distribution. This will be explained with reference to FIG.

FIG. 8 is an explanatory diagram of the force exerted on the electron beam B by the vinctusion magnetic field. As shown in the figure, the vinctusion magnetic field acts perpendicularly (in the y-axis direction) to the electron beam B passing through the magnetic field. A force F acts in a direction that strengthens the focusing, and a force F acts in a direction that weakens the focusing in the horizontal direction (X-axis direction). For this reason, as shown in FIG. 7, each electron beam spot at the periphery of the screen in the horizontal direction is strongly overfocused in the vertical direction, and a halo HA is generated in the vertical direction, and a halo HA is generated in the horizontal direction. The core CO becomes spread out due to insufficient focusing. This causes a decrease in resolution around the screen.

In order to solve the above resolution degradation, in the single electron gun three-beam electron gun, a correction quadrupole is installed to cancel the quadrupole-like distortion caused by the self-convergence deflection yoke, and the electron beam is vertically aligned in advance. A method is used to distort the image.

9 and 10 are explanatory diagrams of the quadrupole distortion correction means in a cathode ray tube equipped with a single electron gun three-beam electron gun, in which 9 is a deflection yoke, 11 is a neck portion, and 12 is a Correction electromagnetic quadrupole; the same symbols as in FIG. 6 correspond to the same parts.

In FIG. 9, a correction electromagnetic quadrupole 12 is provided around the outer periphery of the main lens portion of the neck portion 11 of the cathode ray tube.

FIG. 10 is an explanatory diagram of the schematic configuration of the correction electromagnetic quadrupole 12 and its magnetic field distribution. By passing a current through the coil 121 that is synchronized with the deflection current applied to the deflection yoke 9, the correction electromagnetic quadrupole 12 is shown as indicated by the arrow. A device that forms a quadrupole magnetic field distribution and applies a dynamic focus voltage to the fourth electrode 4 (focusing electrode) of the electron gun to correct spot distortion at the periphery of the screen caused by the self-convergence deflection yoke 9. It is.

Further, as another means for correcting spot distortion in the peripheral area of the screen by the self-convergence deflection yoke 9, there is known a method disclosed in Japanese Patent Laid-Open No. 64-65752.

FIGS. 11 and 12 are explanatory diagrams of another correcting means for the above-mentioned quadrupole distortion in a cathode ray tube equipped with a single electron gun three-beam type electron gun.

In FIG. 11, the fourth electrode (G, ) 4 of the electron gun is divided into three parts, G41. G4□, G43, a constant fixed focus voltage is applied to the central electrode G4□, and the electrodes G4. A dynamic focus voltage is applied to G43 and G43.

In the figure, h41. h4□ and h43 are electrodes G, respectively.
,,C.

4□ is the electron beam passing aperture of G43, and as shown in FIG. 12, the electron beam passing aperture h4. and h43 are horizontally elongated openings with long sleeves in the X-axis direction (horizontal direction), and electron beam passing aperture h4 of electrode G4□
□ is a vertically long opening with long sleeves in the y-axis direction (vertical direction).

As described above, a constant fixed focus voltage is applied to the central electrode G4□, and the electrodes G4. By applying a dynamic focus voltage to G and G43, when the electron beam is at the scanning position at the center of the screen, the electrode G
, ,c, □, G43 are at the same potential, and the three electrodes G41 . x −y formed by Ga□, G43 part
The electric field distribution in the cross section is rotationally symmetrical with respect to the tube axis (two axes), and the cross-sectional shape of the electron beam is circular as shown in FIG. 12(a).

On the other hand, when scanning the peripheral part of the screen, the dynamic focus voltage increases as the deflection angle increases, so that the electron beam of the central electrode G4□ of the fourth electrode G4 is Passage opening h4□
and each electron beam passing aperture h of electrodes G41 and G43 on both sides.
Due to the influence of the narrow parts of 41 and h43, a quadrupole effect occurs in the electric field distribution, and a force that spreads in the y-axis direction and narrows in the x-axis direction is applied to the electron beam, and its cross-sectional shape changes in the y-axis direction. Becomes portrait with long sleeves.

In other words, the electrostatic quadrupole chamber field generated by the dynamic focus voltage creates a distortion rotated 90 degrees with respect to the quadrupole distortion caused by the self-convergence deflection yoke, and the beam spot distortion caused by the self-convergence deflection yoke magnetic field is automatically adjusted. I am trying to correct it.

[Problem to be solved by the invention]

But the former! Those using a magnetic quadrupole magnetic field have the following problems.

(1) A coil device for the electromagnetic quadrupole is required on the outer periphery of the neck, and its position must be accurately selected (selecting the position relative to the fourth electrode, which is the focusing electrode), making the assembly manufacturing process difficult. It becomes complicated.

(2)! ! A circuit means for supplying a current synchronized with the deflection current to the four-electrode coil self-comparison deflection yoke is required, resulting in high cost.

(3)! Since it is necessary to energize the magnetic quadrupole coil, the power consumption of the cathode ray tube increases.

The latter method using an electrostatic quadrupole electric field has the following problems.

(1) Fourth electrode G41 divided into three parts. Ga□, G43
The assembly and manufacturing process becomes complicated because it is necessary to accurately align the axes of the parts.

(2) During dynamic focusing, due to the electric field generated by the fourth electrode C, , C, □, G43, which is divided into three parts,
The position where the electron beams intersect deviates from the Franhofer condition, and comatic aberration occurs because the Franhofer condition does not completely match the center of the main lens, making it impossible to form a circular beam spot.

It is an object of the present invention to solve the problems of the prior art described above, to improve resolution by reducing the diameter of the electron beam spot on the screen, and to correct deflection distortion of the electron beam spot at the periphery of the screen. An object of the present invention is to provide a cathode ray tube which can reduce spot distortion and coma aberration and can obtain highly accurate convergence over the entire screen.

[Means to solve the problem]

The above-mentioned purpose is to provide the above-mentioned method in the vicinity of the main lens constituting an electron gun, which is provided with an electron beam deflection section consisting of an electrostatic deflection means for horizontally deflecting the side electron beam and achieving convergence on the screen side of the main lens. An electron beam path changing section is provided to change the position of the side electron beam passing through the electron beam deflection section consisting of electrostatic deflection means, and a dynamic focus voltage is applied to the electron beam path changing section, and vertical and horizontal deflection magnetic fields are applied to the electron beam path changing section. This is achieved by a configuration with at least one of barrel distribution and uniform distribution.

[Function] A dynamic deflection current synchronized with the deflection current flowing through the deflection yoke is applied to the electron beam path changing section provided near the main lens (for example, one of the two divided focusing electrodes or the electrostatic deflection means provided near the focusing electrode). The electric field generated by applying the focus voltage is the outer electron beam (
act to change the trajectory of the side electron beam).

In other words, the outer electron beam can be passed through a position near the center of the main lens that satisfies the Franhofer condition when a dynamic focus voltage is applied.

This prevents coma aberration from occurring in the electron beam even during dynamic focusing.

The trajectory of the outer electron beam deflected in this way passes beyond the electrostatic deflection means on the screen side, so even if the electron beam is deflected to the periphery of the screen by the barrel magnetic field, it will not be overconcentrated. , can be properly converged.

Furthermore, by setting the magnetic field generated by the deflection yoke to be a barrel magnetic field or a uniform magnetic field, even when the electron beam is deflected in the horizontal direction, beam distortion does not occur, and a small beam spot can be obtained over the entire screen of the screen.

〔Example〕

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

FIG. 1 is a configuration diagram illustrating an embodiment of a cathode ray tube according to the present invention, where l is a first electrode (G1), 2 is a second electrode (G1), and 2 is a second electrode (G1).
cz ), 3 is the third electrode (G3), 4 is the fourth electrode (G,
), 50.60 is an electron beam trajectory, 61.62 is a pair of second electrostatic deflection plates, and 71 and 72 are a pair of first electrostatic deflection means constituting an electron beam path deflection section. The deflection plates 8L82 and 83 are cathodes (Km,
Kc, Ks), 9 is a deflection yoke, 10 is a screen, and each electrode 1, 2,
3.4 are commonly arranged.

The cathodes 81, 82, 83, the first electrode 1, and the second electrode 2 form a triode part, and the cylindrical third electrode 3 and fourth electrode 4 form a high potential type main lens. The third electrode 3 is divided into Gel and G3□, and ciz is further divided into two, G3□ and G3□2.

The first electrostatic deflection plates 7e and 72 are provided between the divided third electrodes 3 (in this embodiment, between G31 and 63□), but this is because the third electrodes 3. It may be provided at a position close to the fourth electrode 4 that influences the focusing action of the main lens.

The first electrostatic deflection plates 71 and 72 also have the effect of increasing the incident angle of the side electron beam incident on the main lens, thereby shortening the axial length of the electron gun.

A second electrostatic deflection means constituting the electron beam deflection section
The electrostatic deflection plate 6L62 is for converging the outer electron beam (side electron beam) that has passed through the main lens formed by the third electrode 3 and the fourth electrode 4 on the screen.

In the same figure, electrode Ga11, electrode G3□1 and second
The electrostatic deflection plate 71 is at the same potential and has a fixed focusing voltage.
, is given.

Here, the voltage of the fourth electrode 4 is set to V, 4. Second electrostatic deflection plate 6
The voltage of 1 is V, and the voltage of the deflection plate 62 is 8. Deflection plate 7
1 voltage is vc (=VF), and the voltage of deflection plate 72 is ■
. When closed, VG4=Vll, VA<Vg, Vc<V
There is a relationship of o.

For example, the cathode has a cutoff voltage of about 170μ,
Adding a video signal to this, the voltage of the first electrode 1 is ground potential,
The voltage of the second electrode is approximately 600 ■, ■ is approximately 8 kV, ■ is approximately 8.5 kV, VO2 (= V8) is 30 kV, VA is approximately 28 kV, electrode G3 □ when deflection is not performed by the deflection yoke. The voltage of 2 is about 8k which is the same potential as electrode G3□1
Let it be V.

In this embodiment, the deflection magnetic field is not a self-convergence type magnetic field, but the vertical and horizontal deflection magnetic fields have a barrel-shaped distribution or uniform distribution, and a dynamic focus voltage is applied in synchronization with the deflection by the deflection yoke 9.

Figure 2 is an explanatory diagram of the force acting on the electron beam B due to the barrel-shaped distributed magnetic field.If the horizontal deflection magnetic field due to the horizontal deflection coil is also barrel-distributed in the horizontal axis direction as shown in the figure, the force acting on the electron beam B is Force F acts on it.

FIG. 3 is an explanatory diagram of the shape of the electron beam spot around the horizontal axis of the screen in this embodiment. As shown in the figure, the distortion of the electron beam spot at the end of the horizontal axis of the screen is eliminated.

However, there is a shift in convergence at the periphery of the screen.

FIG. 4 is an explanatory diagram of the above convergence deviation,
With the magnetic field distribution described above, the three electron beams that were concentrated at one point in the center of the screen are now transformed into raster shapes B, BR, B is inconsistent.

Therefore, in this embodiment, by applying a dynamic focus voltage to the two-divided electrode G3□2 in synchronization with the deflection by the deflection yoke 9, the three electron beams can be properly converged even in the peripheral area of the screen. At the same time, the electron beam spot diameter was reduced.

This will be explained in detail below.

As shown in FIG. 1, side electron beam B.

B8 travels through the triode in parallel with the center electron beam B.

By the action of the first electrostatic deflection plates 71, 72, the side electron beams B, , B are deflected so as to be incident near the center of the main electron lens, that is, at a position that satisfies the Franhofer condition.

Therefore, the three electron beams intersect at this position, and then the side electron beams BR,
Bl is deflected by the action of the second electrostatic deflection plates 61, 62 so as to converge to one point on the screen.

In other words, when the three electron beams are concentrated at the center of the screen and the horizontal deflection coil of the deflection yoke 9 begins to deflect them, the three electron beams are deflected in front of the screen due to the barrel-shaped distributed magnetic field. I end up concentrating, and I end up overconcentrating on the screen.

Therefore, a constant focus voltage is applied to the electrode G3□1 of the third electrode divided into two, and a dynamic focus voltage that changes depending on the amount of deflection by the deflection yoke is applied to the electrode G3□2.

FIG. 5 is a waveform diagram of the dynamic focus voltage, which has a parabolic voltage shown by a curve 3 in which one period is one vertical scanning period, and a curve 4 in which one period is one horizontal scanning period. The voltage waveform is selected such that the parabolic voltage shown in is superimposed.

In other words, when the electron beam is at the scanning position in the center of the screen, the electrodes G3□ and G32□ are at the same potential, and the trajectories of the side beams BR and Bl are as shown in the solid line 50 in FIG.
It becomes as shown in .

On the other hand, when the electron beam is at the scanning position around the screen, due to the lens action of the electrode Cr5ZI and the electrode G3□2, the side beams Bll, B! Even if the + trajectory changes and the Franhofer condition changes due to the application of the dynamic focus voltage, the side beams B, , B can be made incident on the main lens so as to appropriately satisfy the Franhofer condition.

Along with this, as shown by the dotted line 60, the side beam B
i and 13m are between the second electrostatic deflection plates 61 and 62,
Since the electrons pass further outside with respect to the electron gun axis, the overconcentration is corrected and convergence occurs properly. Moreover, since the distribution of the deflection magnetic field is barrel-shaped or uniform, there is no distortion of the electron beam spot, so the diameter of the electron beam spot can be reduced even at the periphery of the screen due to the effect of dynamic focusing, and the resolution can be improved at the front of the screen.

In the above embodiment, the structure is such that a dynamic focus voltage that changes depending on the amount of deflection by the deflection yoke is applied to the electrode G3!2, but the present invention is not limited to this structure.
A similar effect can be obtained by applying a dynamic focus voltage between the first electrostatic deflection plates 71 and 72.

Furthermore, in the embodiment shown in FIG. The installation position of the deflection plate is not limited to the above-mentioned position, but may be any position that influences the main lens so as to satisfy the above-mentioned Franhofer condition according to the deflection action of the deflection yoke.
If this condition is met, it is also possible to arrange the lens on the screen side of the main lens.

In the above description, the electrostatic deflection means constituting the electron beam path deflection section and the electron beam deflection section is described as a flat electrostatic deflection plate to simplify the explanation, but the present invention is not limited to this. Rather, it can be constructed with various shapes and structures, such as a plate body curved or bent along the electron beam passage path, or a rectangular structure.

In the above embodiments, the present invention was applied to a high potential type electron gun, but the present invention can also be applied to a unipotential type electron gun. However, as explained in the above-mentioned prior art, the unipotential electron gun uses three electrodes in the main lens, and the length of the intermediate electrode is extended to lengthen the lens action area, and the spherical surface of the center electron beam is Although it has the advantage of being able to reduce aberrations, since the side electron beams are configured to be obliquely incident on the main lens, the longer the active area of the main lens, the greater the astigmatism. Therefore, even if the voltage ratio between the electrodes is changed, the beam spot diameter of the side electron beam cannot be reduced.

For this reason, the present invention is basically not limited to the type of electron gun, but its effects are significant in the pi-potential type electron gun shown in the above embodiments.

[Effects of the Invention] As explained above, according to the present invention, good convergence can be achieved in both the center and the periphery of the screen without requiring any special correction means for quadrupole distortion correction. At the same time, there is no distortion of the electron beam spot,
In addition, since the spot diameter can be made small over the entire screen, it is possible to provide a cathode ray tube with excellent functionality capable of displaying high-resolution video/images.

[Brief explanation of drawings]

Fig. 1 is a block diagram explaining an embodiment of a cathode ray tube according to the present invention, Fig. 2 is an explanatory diagram of the force acting on an electron beam due to a barrel-shaped distributed magnetic field, and Fig. 3 is a screen horizontal axis in an embodiment of the present invention. Fig. 4 is an explanatory diagram of the electron beam spot shape around the direction, Fig. 4 is an explanatory diagram of the convergence shift, Fig. 5 is a waveform diagram of the dynamic focus voltage, and Fig. 6 is a diagram of the conventional single electron gun three-beam electron gun. A schematic diagram explaining the configuration, Figure 7 is an illustration of spot distortion of the electron beam due to the self-convergence deflection yoke, Figure 8 is an illustration of the force exerted on the electron beam by the binction type magnetic field, and Figures 9 and 10. 11 and 12 are explanatory diagrams of the correction means for quadrupole distortion in a cathode ray tube equipped with a single electron gun three-beam electron gun, and FIGS. FIG. 7 is an explanatory diagram of another correction means for quadrupole distortion. 1...First electrode (G,), 2...Second electrode (c
z ), 3...Third electrode (G:l), 4...
Fourth electrode (G4), 50.60 ... Electron beam trajectory, 61.62 ... Second electrostatic deflection plate, 71
゜72...First electrostatic deflection plate, 81, 82.83...
...Cathode, 9...Deflection yoke, 10...Screen. Figure 2 Figure 3 Figure 4 Figure 7 B Figure 9 Figure 10

Claims (1)

[Claims] 1. An electron beam source that generates a plurality of electron beams, a triode section that controls electron beam emission from the electron beam source, and a main lens that focuses the electron beam emitted from the triode section. A cathode ray tube having an electron gun having at least an electron beam deflection section comprising an electrostatic deflection means for concentrating the electron beam on the screen side of the main lens section on the screen side of the main lens section; A cathode ray tube comprising a path changing section for changing the passage position of the electron beam passing through the electron beam deflecting section. 2. An electron beam source that generates three electron beams, a triode section that controls electron beam emission from the electron beam source, a main lens section that focuses the electron beam emitted from the triode section, and a main lens. an electron gun comprising at least an electron beam deflection section comprising an electrostatic deflection means for concentrating outer electron beams of the electron beams on the screen side of the screen; In a cathode ray tube comprising a deflection yoke for scanning in the vertical and horizontal directions, the focusing electrode constituting the main lens is divided into a first electrode part and a second electrode part, and the focusing electrode is arranged close to the focusing electrode. 1. A cathode ray tube characterized in that the cathode ray tube is further provided with another electron beam deflection section consisting of electrostatic deflection means. 3. In claim 2, a fixed focusing voltage is applied to the first electrode portion and the other electron beam deflection portion, and a dynamic focusing voltage is applied to the second electrode portion, and
A cathode ray tube characterized in that the vertical and horizontal deflection magnetic fields of the deflection yoke have at least one of barrel distribution and uniform distribution. 4. In claim 3, the first electrode portion and the second electrode portion
A cathode ray tube, characterized in that a fixed focusing voltage is applied to the electrode portion of the tube, and a dynamic focusing voltage is applied to the other electron beam changing portion. 5. The cathode ray tube according to claim 1, wherein the main lens is a high potential type electron lens.