JPH06223737A - Color cathode-ray tube device - Google Patents

Abstract

PURPOSE:To obtain a high resolution along the whole area of a phosphor screen with a low dynamic voltage, by forming the electron beam passage hole of the second electrode element of the fourth grid in an elliptical hole smaller than the diameter of the electron beam passage holes of the first and the third elements and the third and the fifth grids. CONSTITUTION:At least to the grids G3 and G5, of an electrode which consists of the first to the sixth grids (G1 to G6) of an electron gun 26 to release three electron beams 25B, 25G, and 25R, circular electron beam passage holes are formed. The grid 4 consists of the first to the third electrode elements (G41 to G43), and a dynamic voltage is applied to the grids G41 and G43, while a constant voltage is applied to the grid G42. Circular electron beam passage holes are formed to the grids G41 and G43, while an elliptical electron beam passage hole in which the direction orthogonal to the alignment of the three electron beams is made as the long axis, and the passage hole diameter of the three electron beams is made smaller than the electron beam passage holes of the grids G41 and G43, and G3 and G5 is formed to the grid G42.

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 device, and more particularly, it corrects the deflection aberration of a color cathode ray tube which emits three electron beams arranged in a row to obtain a high resolution over the entire phosphor screen. The present invention relates to a color cathode ray tube device equipped with an electron gun.

[0002]

2. Description of the Related Art Generally, in a color cathode ray tube device, as shown in FIG. 8, a shadow mask 3 is provided inside a panel 1 so as to face a phosphor screen 2 consisting of a three-color phosphor layer formed on the inner surface of the panel 1. 3 electron beams 7B, 7 emitted from an electron gun 6 arranged and arranged in the neck 5 of the funnel 4.
G and 7R are deflected by the horizontal and vertical deflection magnetic fields generated by the deflection device 8 mounted on the outside of the funnel 4, and the phosphor screen 2 is horizontally and vertically scanned through the shadow mask 3 to produce a color image. It is formed into a structure for reproduction.

In such a color cathode ray tube device,
In particular, the electron gun 6 is an in-line type electron gun that emits three electron beams 7B, 7G, 7R arranged in a row passing through the same horizontal plane, while the deflection device is generated as shown in FIGS. 9 (a) and 9 (b). A self-convergence in-line type color cathode ray tube device that uses a pin-cushion type horizontal deflection magnetic field 10H and a barrel type vertical deflection magnetic field 10V to concentrate the three electron beams 7B, 7G, 7R arranged in a row is now available. Has become the mainstream of color cathode ray tube devices.

By the way, as a problem of this self-convergence in-line type color cathode ray tube device, when the electron beams 7B, 7G, and 7R are deflected from the central portion to the peripheral portion of the phosphor screen, the phosphor screen is deflected due to deflection aberration. However, there is a problem that the beam spot becomes large in the peripheral portion and the resolution deteriorates.

The following two deflection aberrations are the deflection aberrations that cause the deterioration of resolution.

One of them is that the distance from the electron gun to the phosphor screen becomes longer as the deflection of the electron beam increases, so that a beam spot with a small diameter and a perfect circle can be obtained at the center of the phosphor screen. Even if the focus voltage is set to 1, the deflection aberration (first deflection aberration) occurs due to the electron beam being in the overfocus state in the peripheral portion of the phosphor screen.

The other one is a deflection aberration (second deflection aberration) caused by the nonuniformity of the deflection magnetic field. That is, as shown in FIG. 9, the self-convergence in-line type color cathode ray tube apparatus uses three electron beams 7B and 7G by a non-uniform deflection magnetic field in which the horizontal deflection magnetic field 10H is a pincushion type and the vertical deflection magnetic field 10V is a barrel type. , 7R are concentrated on the phosphor screen. Therefore, the electron beams 7B, 7G, and 7R that have passed through the non-uniform deflection magnetic field are horizontally diverged and vertically converged, and in the underfocus state, they are elliptical with the major axis in the horizontal direction. The beam spot becomes non-circularly distorted in the peripheral portion of the phosphor screen. As a result, as shown in FIG. 10, the beam spot 12a in the central portion of the phosphor screen 2 is
Even if is a perfect circle, the peripheral beam spot 12b is distorted into a non-circular shape composed of a high-luminance core portion 13 and a low-luminance halo portion 14 extending in the vertical direction, and the resolution of the peripheral portion of the phosphor screen 2 is significantly different. Deteriorate.

As a means for correcting the shape of the beam spot 12b which deteriorates the resolution of the peripheral portion of the phosphor screen 2, Japanese Patent Laid-Open No. 63-14725 discloses an electron gun in a row as shown in FIG. A quadrapotential type electron gun consisting of three cathodes K arranged and the first to sixth grids G1 to G6 arranged in the direction of the phosphor screen sequentially adjacent to the cathode K, and the fourth grid G4
Is divided into first, second, and third electrode elements G41, G42, and G43 sequentially arranged in the direction from the third grid G3 to the fifth grid G5, and as shown in FIG. 12, the first and third electrode elements are divided.
Three circular electron beam passage holes 16 and 17 are formed in G41 and G43 corresponding to the three cathodes K, and the second electrode element G42 is formed.
In the figure, an electron beam passage hole 18 having a shape in which a long longitudinal slit and a circular electron beam passage hole are superposed is formed in the arrangement direction of the three cathodes K, that is, in the direction orthogonal to the arrangement direction of the three electron beams. Has been done.

In this electron gun, the same voltage Vg2 as that of the second grid G2 is applied to the second electrode element G42 of the fourth grid G4 to increase the deflection of the electron beam to the first and third electrode elements G41 and G43. Dynamic voltage V that increases with
g4, that is, the voltage when the deflection current is zero is the reference voltage Vg4
A voltage gradually increasing from Vg40 is applied as the deflection current increases.

In this electron gun, when the electron beam is deflected by applying such a voltage, the fourth grid G4
A non-rotationally symmetric lens is formed between the three electrode elements G41, G42, G43 to correct the second deflection aberration caused by the inhomogeneity of the deflection magnetic field. Furthermore, the first and third electrode elements G41, G43
As the dynamic voltage Vg4 applied to the second grid G5 increases, the intensity of the sub-lens (UPF lens) formed between the third and fifth grids G3 and G5 weakens, and the focusing voltage Vf applied to the fifth grid G5 decreases. When the distance is constant, the strength of the entire main lens system including the main lens (BPF lens) formed between the fifth and sixth grids G5 and G6 and the sub-lens is weakened, and the first deflection aberration is also corrected. As a result, it is possible to correct the deflection aberration in the peripheral portion of the phosphor screen and reduce the beam spot.

However, in this electron gun, since the electron beam passage hole having the vertically long slit is formed in the second electrode element G42 of the fourth grid G4, each electrode element G41, G42, G43 of the fourth grid G4 is formed. Even if the same voltage is applied to
A non-rotationally symmetric lens is formed by the electric field penetrating from the third grid G3 and the fifth grid G5, and has the effect of making the electron beam passing through this lens vertically long. Therefore, when the electron beam is not deflected, it is necessary to eliminate this effect. Therefore, the voltage Vg40 applied to the first and third electrode elements G41 and G43 is the voltage Vg applied to the second electrode element G42.
Must be lower than g2. In this case, the sub-lens formed between the third and fifth grids G3 and G5 becomes stronger than necessary, and the magnification of the main lens system becomes inappropriately large.
As a result, the beam spot on the phosphor screen becomes large.

As a countermeasure, the electron gun is
Further, as shown in FIG. 13, the first and third electrode elements G41,
It is shown that the electron beam passage holes 16 and 17 of G43 have a shape in which a laterally long slit long in the arrangement direction of three electron beams and a circular electron beam passage hole are overlapped (only for the first electrode element G41). (Shown). In this case, when the electron beam is not deflected, the voltage Vg40 applied to the first and third electrode elements G41 and G43 is the voltage Vg2 applied to the second electrode element G42.
Can be the same as However, the first and third electrode elements
Since the diameters of the electron beam passage holes 16 and 17 of G41 and G43 in the horizontal direction become large, the third by applying a dynamic voltage,
The correction effect of the sub lens between the fifth grids G3 and G5 is weakened and becomes insufficient. Therefore, the dynamic voltage required to correct the deflection aberration becomes high, and the reliability of the withstand voltage of the cathode ray tube becomes a problem. Also, this increases the cost of the dynamic voltage generation circuit.

[0013]

As described above, the electron gun for emitting three electron beams arranged in a row is provided, and the three electron beams are concentrated on the phosphor screen by the non-uniform magnetic field generated by the deflecting device. The self-convergence in-line type color cathode ray tube device has a problem that the beam spot in the peripheral portion of the phosphor screen becomes large and the resolution is deteriorated due to the deflection aberration. In order to solve the problem of this self-convergence in-line type color cathode ray tube device and to improve the resolution over the entire phosphor screen, the electron gun is of a quadrapotential type including a cathode and first to sixth grids, and The fourth grid is divided into three electrode elements (first to third electrode elements), and the same voltage Vg2 as that of the second grid is applied to the second electrode element located in the middle between the third grid and the fifth grid. There is a color cathode ray tube device in which a dynamic voltage that increases as the deflection of the electron beam increases is applied to the first and third electrode elements located on the side.
In the electron gun of this color cathode ray tube device, among the three divided electrode elements of the fourth grid, circular electron beam passage holes are formed in the first and third electrode elements, and the second electrode element is formed. 3. An electron beam passage hole having a shape in which a vertically long slit and a circular electron beam passage hole are overlapped with each other in a direction orthogonal to the arrangement direction of the three electron beams, or the electron beam passage holes of the first and third electrode elements are provided with three electrons. It is formed in a shape in which a horizontally elongated slit long in the beam arrangement direction and a circular electron beam passage hole are overlapped.

However, in such an electron gun, the beam spot on the phosphor screen becomes large. Further, the dynamic voltage applied to the first and third electrode elements becomes high, and the reliability of the withstand voltage of the cathode ray tube becomes a problem. Further, there is a problem that the cost of the dynamic voltage generating circuit is increased.

The present invention has been made to solve the above-mentioned problems, and has three cathode electrodes and first to sixth grids, the fourth grid of which is composed of first to third electrode elements. In an in-line type color cathode ray tube device including an electron gun, which is divided into electrode elements, and a dynamic voltage that increases with an increase in deflection of an electron beam is applied to the first and third electrode elements, a phosphor with a low dynamic voltage The purpose is to obtain high resolution over the entire screen.

[0016]

An electron gun having a plurality of electrodes for emitting three electron beams arranged in a row passing through the same plane and a deflecting device for deflecting the three electron beams are provided. The first to sixth grids are sequentially arranged from the cathode in the phosphor screen direction, and circular electron beam passage holes are formed in at least the third and fifth grids of the first to sixth grids, and the fourth grid is formed. Is the third
The first to third electrode elements are sequentially arranged from the grid in the fifth grid direction, and increase with the deflection of the electron beam to the first and third electrode elements among the first to third electrode elements. In a color cathode ray tube device in which a dynamic voltage is applied and a constant voltage is applied to the second electrode element, circular electron beam passage holes are formed in the first and third electrode elements, and three electron beams are applied to the second electrode element. The major axis of which is the direction orthogonal to the arrangement direction of the electron beams, and the diameters of the electron beam passage holes in the arrangement direction of the three electron beams are
An elliptic electron beam passage hole smaller than the diameter of the electron beam passage hole of the fifth grid was formed.

[0017]

As described above, the first to sixth grids are sequentially arranged in the direction from the cathode to the phosphor screen, and the fourth grid is arranged.
The grid is divided into three electrode elements consisting of first to third electrode elements, circular electron beam passage holes are formed in the first and third electrode elements, and the arrangement direction of three electron beams in the second electrode element. An elliptical shape having a major axis in a direction orthogonal to and electron beam passage holes in the arrangement direction of the three electron beams smaller than the diameters of the electron beam passage holes of the first, third electrode elements and the third and fifth grids. By forming the electron beam passage hole, the dynamic voltage applied to the first and third electrode elements can be lowered, and the beam spot in the peripheral portion of the phosphor screen can be made small, resulting in good resolution over the entire phosphor screen. Can be

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1A shows a color cathode ray tube device which is an embodiment of the present invention. This color cathode ray tube device is a panel
The panel 20 has an envelope composed of a funnel-shaped funnel 21 integrally joined to the panel 20, and the panel 20 has an inner surface formed of a stripe-shaped three-color phosphor layer that emits blue, green, and red light. A phosphor screen 22 is provided, and a shadow mask 23 is arranged inside the phosphor screen 22 so as to face the phosphor screen 22. On the other hand, inside the neck 24 of the funnel 21,
A row of three electron beams 25B and 25G that pass on the same horizontal plane
, 25R, which will be described later, are provided. A deflection device 28 is mounted outside the boundary between the large diameter portion 27 of the funnel 21 and the neck 24. Then, the three electron beams 25B, 25G, 25R emitted from the electron gun 26 are deflected by the magnetic field generated by the deflecting device 28, and the phosphor screen 22 is horizontally and vertically scanned to reproduce a color image. Is formed into a structure.

As shown in FIG. 1B, the electron gun 26 has three cathodes K arranged in a line in the horizontal direction, and three heaters (not shown) for heating the three cathodes K separately. No.), the first to sixth grids G1 are sequentially arranged at a predetermined distance from the cathode K in the phosphor screen direction.
It is composed of quadra potential type consisting of ~ G6. Each of the grids G1 to G6 is composed of an electrode having an integral structure, and in particular, with respect to the fourth grid G4, the first to third electrode elements G41 to G41 are sequentially divided and arranged in the direction from the third grid G3 to the fifth grid G5. It consists of G43.

The first, second and sixth grids G1, G2, G
On the second grid G2 side of the third grid G3 and the sixth grid G6 side of the fifth grid G5, three circular electrons of a predetermined size in the horizontal direction are provided corresponding to the three cathodes K 6. The beam passage holes are arranged in a line. 4th grid
Regarding G4, in the first and third electrode elements G41, G43,
As shown in FIG. 2, a groove 30 extending in the horizontal direction is formed at the center of the surface facing the second electrode element.
At the bottom of the, corresponding to the three cathodes K, the diameter W1 of 3
The circular electron beam passage holes 31 are provided in a line. Further, as shown in FIG.
Corresponding to each cathode K, three vertically elongated elliptical electron beam passage holes 32 are provided in the vertical direction. The horizontal diameter W2 of the electron beam passage hole 32 of the second electrode element G42 is equal to the diameter W1 of the electron beam passage hole 31 of the first and third electrode elements G41 and G43 and the third and fifth grids G3 and G5. The diameter is smaller than the diameter of the electron beam passage hole, and W1> W2.

In such an electron gun 26, the cathode K
A voltage of 50 to 150 V is applied to the first grid G1.
Is the ground potential, and the second grid G2 has 600 to 1000
V, the third grid G3 and the fifth grid G5 are connected in a tube, and the focusing voltage Vf of 8 kV is 27 kV on the sixth grid G6.
Anode high voltage is applied. Also the second of the fourth grid G4
The electrode element G42 is connected to the second grid G2 in the tube, a voltage of 600 to 1000 V which is the same as the voltage Vg2 of the second grid G2 is applied, and the first and third electrode elements G41 and G43 are connected in the tube. As shown in FIG. 4, these electrode elements G41 and G43 use a voltage Vg2 of the second grid G2 as a reference voltage, and a voltage that changes in synchronization with the deflection current 34 flowing in the deflection device, that is, the deflection of the electron beam. The dynamic voltage Vg4 shown by the curve 35 in which the voltage increasing with the increase of the voltage is superimposed is applied.

By applying such a voltage, in this electron gun, a sub-lens is formed between the third to fifth grids G3 and G5, and a main lens is formed between the fifth and sixth grids G5 and G6. . Also, three electrode elements G41, G4 of the fourth grid G4
A non-rotationally symmetric lens is formed between 2 and G43. The strength of this non-rotationally symmetric lens is changed by the dynamic voltage Vg4 applied to the first and third electrode elements G41 and G43,
The second deflection aberration caused by the inhomogeneity of the deflection magnetic field is corrected according to the deflection of the electron beam. Further, the dynamic voltage Vg4 applied to the first and third electrode elements G41 and G43 weakens the strength of the sub-lens formed between the third to fifth grids G3 and G5, and the electron beam becomes overfocused. The first deflection aberration caused by this is also corrected.

That is, as described above, the electron beam passage hole 32 of the second electrode element G42 of the fourth grid G4 has the horizontal diameter W2 of the electron beam passage hole 31 of the first and third electrode elements G41, G43. If the diameter W1 and the diameters of the electron beam passage holes of the third and fifth grids G3 and G5 are smaller and W1> W2, the potential distribution inside the fourth grid G4 is shown in FIG. The potential distribution in the horizontal direction is as shown. Note that FIG. 6 shows the potential distribution in the horizontal direction of the central electron beam passage hole inside the fourth grid G4 of the conventional electron gun of W1 = W2 shown for comparison.

5 and 6, the voltages Vg3 and Vg5 applied to the third and fifth grids G3 and G5 are set to Vg3 = Vg5 = 8.0 kV and the first and third grids are used when the electron beam is not deflected. The voltage Vg40 applied to the electrode elements G41, G43 is Vg40 = 800V, and the voltage Vg4 applied to the first and third electrode elements G41, G43 when deflecting the electron beam is shown as Vg4 = Vg40 + 800V. .

When the electron beam is not deflected, in the electron gun of this example, the potential distribution in the horizontal direction of the electron beam passage hole at the center inside the fourth grid G4 is shown in FIG.
As shown by a, the conventional electron gun shown in FIG.
It becomes as shown by the equipotential line 37b. When the electron beam is deflected, the equipotential line 38a in the electron gun of this example is shown in FIG.
The equipotential line 38b is shown in FIG.

5 (a), 5 (b) and 6
As is clear from the comparison between (a) and (b), assuming that W1> W2 as in the electron gun of this example, the potential distribution inside the fourth grid G4 is the same as that of the conventional electron gun in which W1 = W2. Compared with the electron beam, it is greatly changed in the region 39 which gives a focusing effect to the electron beam. In particular, the equipotential lines 37a and 38a in the central part greatly change compared to 37b and 38b,
Third and fifth grids G3, G5, first to third electrode elements G41
When the above voltage is applied to G43, the equipotential line in the center
37a and 38a are 3.5kV, and the beam spot can be greatly reduced with a low dynamic voltage.

However, the second electrode element G42 of the fourth grid G4
If the horizontal diameter W2 of the
Although the spherical aberration inside G4 increases and the beam spot can be reduced with a low dynamic voltage, the beam spot diameter becomes larger than in the above case. FIG. 7 shows the ratio of the horizontal diameter W2 of the second electrode element G42 to the diameter W1 of the electron beam passage hole 31 of the first and third electrode elements G41, G43 at the diagonal portion of the phosphor screen with respect to the ratio W2 / W1. A curve 40 shows the relationship with the beam spot diameter, and a curve 41 shows the relationship with the optimum dynamic voltage. These curves 40,
As is clear from 41, the range in which the beam spot diameter at the diagonal portion of the phosphor screen is not deteriorated at a low dynamic voltage is W2 ≧ 0.88W1.

[0029]

The electrodes of the electron gun having a plurality of electrodes for emitting three electron beams arranged in a line passing through the same plane are composed of first to sixth grids arranged in order from the cathode in the phosphor screen direction. Circular electron beam passage holes are formed in at least the third and fifth grids of the first to sixth grids, and the fourth to fourth electrodes are sequentially arranged from the third grid to the fifth grid direction. The first to third electrode elements, and the first and third electrode elements.
In the color cathode ray tube device in which a dynamic voltage that increases with an increase in the deflection of the electron beam is applied to the electrode element and a constant voltage is applied to the second electrode element,
A circular electron beam passage hole is formed in the third electrode element,
The electrode element has a major axis in the direction orthogonal to the arrangement direction of the three electron beams, and the diameters of the electron beam passage holes in the arrangement direction of the three electron beams are the first and third electrode elements and the electrons of the third and fifth grids. By forming an elliptical electron beam passage hole smaller than the diameter of the beam passage hole, the dynamic voltage applied to the first and third electrode elements can be lowered, and the beam spot around the phosphor screen can be reduced. Therefore, the resolution can be improved over the entire phosphor screen.

[Brief description of drawings]

FIG. 1 (a) is a diagram showing a configuration of a color cathode ray tube device according to an embodiment of the present invention, and FIG. 1 (b) is a diagram showing a configuration of an electron gun thereof.

2 (a) is a plan view of the first and third electrode elements of the fourth grid of the electron gun, FIG. 2 (b) is a sectional view taken along the line BB, and FIG. 2 (c) is a sectional view thereof. It is a -C line sectional view.

FIG. 3 (a) is a second grid of the fourth grid of the electron gun.
A plan view of the electrode element, FIG. 3B is a sectional view taken along the line BB,
FIG.3 (c) is the CC sectional view taken on the line.

FIG. 4 is an explanatory diagram of a dynamic voltage applied to the first and third electrode elements of the fourth grid.

FIG. 5 (a) is a diagram showing a potential distribution obtained inside the fourth grid of the electron gun when the electron beam is not deflected, and FIG. 5 (b) is an electron beam when the electron beam is deflected. It is a figure which shows the electric potential distribution obtained inside the 4th grid of a gun.

6 (a) is a diagram showing a potential distribution obtained inside a fourth grid when the electron beam of the conventional electron gun is not deflected, and FIG. 6 (b) is a diagram showing the potential distribution when the electron beam is deflected. It is a figure which shows the electric potential distribution obtained inside the 4th grid of an electron gun.

FIG. 7 shows a beam with respect to a ratio of a horizontal diameter of a vertically elongated elliptical electron beam passage hole of a second electrode element of a fourth grid in the electron gun to a diameter of a circular electron beam passage hole of the first and third electrode elements. It is a figure which shows the relationship with a spot diameter, and the relationship with an optimal dynamic voltage.

FIG. 8 is a diagram showing a configuration of a conventional color cathode ray tube device.

FIG. 9A is a diagram showing a pincushion type horizontal deflection magnetic field of the deflection device, and FIG. 9B is a diagram showing a barrel type vertical deflection magnetic field.

FIG. 10 is a diagram showing a shape of a beam spot on a phosphor screen.

FIG. 11 is a diagram showing a configuration of a conventional improved electron gun.

FIG. 12 is a diagram showing a configuration of a fourth grid of the electron gun.

13 (a) is a plan view showing a different structure of a second electrode element forming the fourth grid of the electron gun, FIG.
3B is a cross-sectional view taken along the line BB.

[Explanation of symbols]

 22 ... Phosphor screen 25B, 25G, 25R ... 3 electron beam 26 ... Electron gun 28 ... Deflection device 31 ... Electron beam passage hole 32 ... Electron beam passage hole G1 ... First grid G2 ... Second grid G3 ... Third grid G4 … Fourth grid G5… Fifth grid G6… Sixth grid G41… First electrode element G42… Second electrode element G43… Third electrode element K… Cathode

Claims (1)

[Claims] 1. An electron gun having a plurality of electrodes for emitting three electron beams arranged in a line passing through the same plane, and a deflecting device for deflecting the three electron beams, wherein the electrode of the electron gun is from a cathode. The first to sixth grids are sequentially arranged in the phosphor screen direction, and circular electron beam passage holes are formed in at least the third and fifth grids of the first to sixth grids, and the fourth grid is the fourth grid. The first to the third grids sequentially arranged from the 3rd grid to the 5th grid direction
The first and third electrode elements of the first to third electrode elements are applied with a dynamic voltage that increases as the deflection of the electron beam increases, and the second and third electrode elements are applied.
In the color cathode ray tube device in which a constant voltage is applied to the electrode elements, circular electron beam passage holes are formed in the first and third electrode elements, and the arrangement direction of the three electron beams in the second electrode element. An ellipse whose major axis is in the direction orthogonal to and the diameter of the electron beam passage holes in the arrangement direction of the three electron beams is smaller than the diameters of the electron beam passage holes of the first and third electrode elements and the third and fifth grids. 1. A color cathode ray tube device having a hole-shaped electron beam passage hole.