JP2001068039A - Color cathode-ray tube and electron gun thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-line type color cathode-ray tube, capable of making uniform the shape of beam spot of three electron beams from the center of screen to the end parts left and right, without complicating the structure of an electron gun. SOLUTION: This color cathode-ray tube is equipped with converging auxiliary lenses 104a, 104b, 104c formed by dividing a convergence electrode into a plurality of segments, and electrode part constituting the auxiliary lenses 104a, 104b, 104c is provided with three electron beam passing holes laid in horizontal arrangement, where the holes 104a1, 104a3, etc., on the sides have the same diameter, and different from the diameter of the holes 104a2, etc., in the center.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for a color cathode ray tube, and more particularly to an electron gun for a high-resolution in-line type color cathode ray tube and a color cathode ray tube equipped with the same.

[0002]

2. Description of the Related Art In order to increase the resolution of a color cathode ray tube, the spot diameter of each electron beam of R (red), G (green), and B (blue) must be reduced. It is necessary to concentrate the spots of the electron beams on one point over the entire area of the screen. Either of them deteriorates the resolution and the image quality.

Generally, in a color cathode ray tube, as shown in FIG. 10, three electron beams 10B, 10G, 10R emitted from three in-line electron guns arranged side by side on the same horizontal plane. FIG. 10A shows a pincushion-like horizontal deflection magnetic field distribution 101 shown in FIG.
The deflection magnetic field 10 of the barrel-shaped vertical deflection magnetic field distribution shown in FIG.
A so-called in-line self-convergence method is adopted in which three electron beams are concentrated at an arbitrary point on the screen by combining the two.

The in-line self-convergence method is
There are many advantages that the electric circuits required for concentrating the three electron beams 10B, 10G, and 10R, adjustment, and the like are small, and that high accuracy can be achieved. However, when the electron beams 10B, 10G, and 10R pass through the self-convergence deflecting magnetic fields 101 and 102, the electron beam spot is affected by the magnetic field distortion. When the beam is deflected to the periphery of the screen, the electron beam has a distorted shape with a horizontally long beam core 111 and radial halos 112 above and below the beam core 111 as shown in FIG. Since the diameter of the distorted electron beam at the periphery of the screen is larger than that of the circular electron beam at the center of the screen, there is a disadvantage that the resolution at the periphery of the screen is significantly deteriorated.

When the distortion of the electron beam shape around the screen is observed in detail, the focus voltage Vfh for minimizing the horizontal diameter of the electron beam is different from the focus voltage Vfv for minimizing the vertical diameter of the electron beam. The voltage difference ΔVf = Vfh-Vfv is negative. That is,
Since the focusing state of the electron beam in the vertical direction is an overfocus state, a halo tends to appear in the vertical direction.

Various proposals have been made as a method for improving the shape of the electron beam around the screen by the self-convergence deflection magnetic field described above. For example, JP-A-61-
In Japanese Patent No. 99249, a vertically elongated electron beam passage hole 123 is provided at an end face of the first focusing electrode 121 on the side of the second focusing electrode 122 like the electron gun 120 shown in FIG. A laterally elongated electron beam passage hole 124 is provided on the end face on the side of the focusing electrode 121, a constant focus voltage is applied to the first focusing electrode 121, and the second focusing electrode 122 is subjected to an increase in the deflection angle of the electron beam. By applying a dynamic focus voltage 131 that changes to a higher value than the first focus voltage as shown in FIG.
As shown in FIG. 14, a quadrupole lens 141 is formed between the focusing electrode 121 and the second focusing electrode 122, and a diverging force 143 is applied to the electron beam 142 in the vertical direction, and the diverging force is applied in the horizontal direction. To compensate for the electron beam distortion caused by the self-convergence magnetic field,
Moreover, a method for obtaining a small beam spot diameter has been proposed.

[0007]

As described above, conventionally, in order to cancel the electron beam distortion due to the self-convergence magnetic field, the focusing electrode is divided into a first focusing electrode and a second focusing electrode, and the focusing electrode is divided into four. A dynamic quadrupole lens is constructed by applying a constant focus voltage to the first focusing electrode and applying a dynamic focus voltage that increases with the deflection angle of the electron beam to the second focusing electrode. Was composed. However, there is a problem that the shape of each of the R, G, and B electron beam spots around the screen is different due to the recent increase in the screen size, the resolution, the wide angle deflection, and the flat screen of the color cathode ray tube. Has become.

This is because the self-convergence magnetic fields received by the R, G, and B electron beams when they pass through the deflecting magnetic field are different. For example, when the beam is deflected to the right side of the screen, in order to concentrate the three electron beams at one point, it is necessary that the R electron beam receives a stronger deflecting magnetic field than the others, and as a result, the R electron beam is deflected by the deflecting magnetic field. The distortion of the beam spot shape is greater than others.

On the other hand, when the electron beam of B is deflected to the left side of the screen, the electron beam of B needs to receive a stronger deflecting magnetic field than the other. The distortion is greater than others.

Therefore, R and B require different amounts of astigmatism correction on the left and right sides of the screen. FIG. 15 shows the state of the conventional R, G, B beam spots around this screen. FIG. 16 shows the dynamic focus voltage originally required for each of R, G, and B for the above reason. Normally, among the three electron beams, the dynamic focus voltage is set so that the shape of the electron beam spot at the center (G) is optimal, so that R and B are dissociated from the optimal dynamic focus voltage. As a result, a halo 151 is generated in the R beam spot on the right side of the screen to degrade the resolution, and a halo 152 is formed on the B beam spot on the left side of the screen.
Is caused, the resolution is degraded, and the resolution of R and B at the left and right ends of the screen is lowered.

In particular, in a recent color cathode ray tube for a display having a high resolution, a wide angle deflection, and a flat screen, the optimal dynamic voltage at both ends (R, B) is dissociated from the optimal focus voltage at the center (G). And the above phenomenon is extremely manifested and becomes a problem. For example, the current 1
In the monitor for a 9-inch wide-angle deflection display, the dynamic focus voltage when the electron beams R, G, and B shown in FIG. 15 are obtained and the state of the R beam spot at the right end of the phosphor screen surface are shown in FIG. As shown in FIG. 16, the dissociation from the focus voltage required to obtain the state of the G beam spot reaches about 150 V as shown in FIG.

To achieve the above object, Japanese Patent Laid-Open Publication No. Hei 10-21847 discloses a configuration in which the beam spot shapes of three electron beams are made as uniform as possible at the left and right ends of a screen. However, this configuration has the problems that the structure of the electron gun becomes complicated and that a new voltage supply pin and a power source for the display set are required.

An object of the present invention is to provide a uniform in-line type color cathode ray tube having a uniform beam spot shape of three electron beams from the center to the right and left ends of a screen without complicating the structure of an electron gun. An object of the present invention is to provide an in-line type color cathode ray tube electron gun and a color cathode ray tube equipped with the same.

[0014]

To achieve the above object, according to a first aspect of the present invention, there is provided an electron beam generating section including a control electrode, and a focusing electrode for focusing the electron beam on a phosphor screen. In an in-line type color cathode ray tube electron gun having a plurality of electrodes including a main electrode including an accelerating electrode, a focusing electrode adjacent to the accelerating electrode is divided into a plurality of parts, and the dynamic focus varies in synchronization with the deflection of the electron beam. Voltage Ec3D and constant focus voltage E
c3S is applied to the plurality of focusing electrodes, and focuses the electron beam in one of the horizontal direction and the vertical direction depending on which of the dynamic focus voltage Ec3D and the constant focus voltage Ec3S is higher. A voltage difference between the dynamic focus voltage Ec3D and the constant focus voltage Ec3S when the dynamic focus voltage Ec3D and the constant focus voltage Ec3S are applied to the quadrupole action lens for generating a force and the divided electrodes. A focusing auxiliary lens for generating a force for focusing the electron beam in both the horizontal direction and the vertical direction with an increase in the number of the electron beam passing holes of the three horizontally arranged electron beam passing holes of the electrode portion constituting the focusing auxiliary lens. The diameter of the side passage holes is the same,
In addition, the hole diameter is different from the diameter of the center passage hole.

According to a second aspect of the present invention, the dynamic focus voltage Ec3D and the constant focus voltage Ec3S always have a relationship of Ec3S> Ec3D, and the three electrode portions constituting the focusing auxiliary lens are arranged horizontally. The hole diameters of the passage holes on both sides of the electron beam passage holes are smaller than the hole diameter of the center passage hole.

According to a third aspect of the present invention, the dynamic focus voltage Ec3D and the constant focus voltage Ec3S always have a relationship of Ec3S <Ec3D, and the three electrode portions constituting the focusing auxiliary lens are arranged horizontally. The hole diameters of the passage holes on both sides of the electron beam passage holes are larger than the hole diameter of the center passage hole.

According to a fourth aspect of the present invention, when the electron lens strength of the plurality of focusing electrodes changes due to the dynamic focus voltage Ec3D, the ratio of the electron lens strength change between the center beam and both side beams is reduced. It is different.

According to a fifth aspect of the present invention, there is provided a color cathode ray tube equipped with the electron gun for a color cathode ray tube according to the first to fourth aspects.

[0019]

[Function and Effect] The lens strength of the main lens composed of the focusing electrode and the accelerating electrode is conventionally weakened by the dynamic focus voltage Ec3D which fluctuates in synchronization with the deflection of the electron beam, so that the center beam and the side beam are almost the same. In the present invention, a focusing auxiliary lens that changes the focusing power in both the horizontal direction and the vertical direction by a dynamic focus voltage Ec3D that changes in synchronization with the increase in the deflection angle is added to the one that has obtained the moving distance of the imaging point. By making the hole diameter of the passage hole at the center of the electron beam passage hole of the electrode constituting the focusing auxiliary lens different from the hole diameter of both ends,
The movement distance of the imaging point can be made different for the center and side beams.

As a result, the dynamic focus voltage of each of the R, G, and B beams can be controlled separately for the center and the side, and the voltage difference between the G beam on the right and left sides of the screen can be balanced. As a result, it is possible to improve the extreme reduction in resolution of R and B at the peripheral edge of the screen, and to make the left and right unbalanced state of the electron beam spot uniform.

By mounting the electron gun of the present invention, a high quality color cathode ray tube having the same resolution of R, G, and B over the entire screen can be realized.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an electron gun for a color cathode ray tube according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a first embodiment 100 of an electron gun for a color cathode ray tube according to the present invention. In FIG. 1, 1
Reference numerals 01B, 101G, and 101R denote cathodes for generating an electron beam, respectively. The electron beam emitted from the cathode is a control electrode 102, an acceleration electrode 103, a first focusing electrode (a) 104a, and a first focusing electrode (b). 104b, the first focusing electrode (c) 104c, the second focusing electrode 105,
It reaches the final acceleration electrode 106, and then reaches the screen. The cathode 101B, 101G, 101R, the control electrode 102, and the acceleration electrode 103 form a three-pole portion, and a main lens is formed between the final acceleration electrode 106 to which the highest voltage is applied and the second focusing electrode 105.

The feature of the present invention is that the conventional first focusing electrode 121 is divided into the first focusing electrode (a) 104a, the first focusing electrode (b) 104b, and the first focusing electrode (c) 104c as described above. That is, a focusing auxiliary lens is formed in this portion. The first focusing electrode (a) 104a and the first focusing electrode (a) 104a
Focusing electrode (b) 104b, first focusing electrode (c) 104c
2 is shown in FIG.

As shown in FIGS. 1 and 2, vertically elongated electron beam passage holes 104c1, 104c2, 104c3 are provided on the second focusing electrode 105 side of the first focusing electrode (c) 104c. As shown, the second focusing electrode 10
5, the first focusing electrode (c) 104c side is provided with horizontally elongated electron beam passage holes 1051, 1052, 1053, and vertically elongated electron beam passage holes 104c1, 104c2,
104c3 and the horizontally elongated electron beam passage holes 1051, 105
An electrostatic quadrupole working lens for correcting astigmatism is formed between the lens and the lens 2,1053.

FIG. 3 shows the first focusing electrode (a) 104a of the first focusing electrode (a).
Focusing electrode (b) 104b side, first focusing electrode (b) 104
b, and the electron beam passing holes 104a1, 1a on the first focusing electrode (b) 104b side of the first focusing electrode (c) 104c.
04a2, 104a3, 104b1, 104b2, 10
4b3, 104c4, 104c5, and 104c6 are shown.
As shown in FIG. 3, the side holes of the electron beam passage holes have the same diameter, and the center hole has a larger diameter than the side holes.

FIG. 4 shows the connection of the focus voltage in the first embodiment of the electron gun shown in FIG. First focusing electrode (a) 1
A constant focus voltage Ec3S is applied to the first focusing electrode (b) 104b and the first focusing electrode (c) 104c.
Then, a dynamic focus voltage Ec3D is applied to the second focusing electrode 105.

With the above configuration, it is possible to make the sensitivity of moving the imaging point of the side electron beam different from the sensitivity of moving the imaging point of the center electron beam, and the difference between the dynamic focus voltages Ec3D originally required for R, G, and B, respectively. Can be reduced.

FIG. 5 shows the waveforms of the constant focus voltage Ec3S and the dynamic focus voltage Ec3D applied to the electrodes in the first embodiment. As shown in FIG. 5, the relationship between the constant focus voltage Ec3S and the dynamic focus voltage Ec3D is always Ec3D <Ec3S. In this case, the first focusing electrode (b) 104b has a maximum inter-electrode potential at the center of the screen, and thus has a maximum focusing power,
Since the inter-electrode potential decreases in synchronization with the increase in the deflection angle, the focusing force is weakened, so that the imaging point moves far.

At this time, since the diameter of the center electron beam passage hole is larger than that of the side electron beam passage hole, the sensitivity of moving the imaging point of the side electron beam becomes larger than that of the center electron beam, and the dynamics required by the side electron beam are increased. The voltage can be made lower than the dynamic voltage required by the center electron beam, and the dynamic focus voltages of R and B, which were conventionally unbalanced with respect to G as shown in FIG. As a result, as shown in FIG. 15, a large halo 151 is conventionally generated around R on the right of the screen, and a large halo 152 is generated around B on the left of the screen, as shown in FIG. However, these halos are the halos 91 and 92 in FIG.
And the resolution is improved.

Next, a second embodiment of the electron gun for a color cathode ray tube according to the present invention will be described.

The second embodiment of the electron gun for a color cathode ray tube according to the present invention has the same basic structure as that shown in FIG. 1 of the first embodiment, but has a side electron beam passage hole and a center as described later. The difference is that the size relationship of the hole diameters of the electron beam passage holes is opposite to that of the first embodiment, and that the size relationship between the constant focus voltage and the dynamic focus voltage is opposite to that of the first embodiment.

FIG. 6 shows a second embodiment of the electron gun for a color cathode ray tube according to the present invention, in which the first focusing electrode (a) is closer to the first focusing electrode (b), the first focusing electrode (b), and the first focusing electrode (b). Each electron beam passage hole 6 on the first focusing electrode (b) side of the focusing electrode (c)
1, 62 and 63 are shown. As shown in FIG. 6, the side holes 61 and 63 of each electron beam passage hole have the same hole diameter, and the center hole 62 has a smaller hole diameter than the side holes 61 and 63.

FIG. 7 shows a constant focus voltage Ec3S and a dynamic focus voltage Ec3D applied to the electrodes. As shown in FIG. 7, the relationship between the constant focus voltage Ec3S and the dynamic focus voltage Ec3D is always Ec3.
D> Ec3S.

6 and 7, the first focusing electrode (b) of FIG. 1 has a minimum focusing force at the center of the screen, and the inter-electrode potential increases in synchronization with the increase in the deflection angle. Becomes stronger, the imaging point moves to the electron gun side. On the other hand, at the same time, the potential difference between the main lens composed of the second focusing electrode 105 and the final accelerating electrode 106 in FIG. 1 decreases with an increase in the dynamic focus voltage Ec3D, so that the focusing effect of the main lens is weakened and the effect of the main lens is reduced. Moves the imaging point far away. That is,
Although the movement of the imaging point is canceled by the first focusing electrode (b) and the main lens, the movement of the imaging point when the dynamic focus voltage Ec3D changes is greater than that of the main lens. By providing the focusing electrode (b), the imaging point movement sensitivity, which is the sensitivity at which the image point moves far when the dynamic focus voltage Ec3D changes by a unit amount, is reduced.

At this time, the diameter of the beam passage hole constituting the first focusing electrode (b) is set to be smaller than the side holes 61 and 63 as shown in FIG.
Have the same hole diameter, and the center hole 62 has side holes 61 and 63.
Because the hole diameter is smaller than that of the side beam, the sensitivity of moving the imaging point of the center beam is lower than that of the side beam, that is, the dynamic focus voltage required for the center beam must be higher than the dynamic focus voltage required for the side beam. The dynamic focus voltages of R and B, which were conventionally unbalanced with respect to G as shown in FIG. 16, can be balanced with respect to G as shown in FIG. Conventionally, R
At the periphery, a large halo occurred around B on the left side of the screen, and the resolution was remarkably deteriorated. This halo was reduced as shown in FIG. 9 and the resolution was improved.

In the above embodiment, the first focusing electrode is divided into three parts. However, the first focusing electrode may be divided into two parts or four or more parts.

Although the shape of the electrode opening is shown as a circle, it may be other shapes such as a square hole, an ellipse, etc., and the focusing power changes in the horizontal and vertical directions of the lens by the dynamic focus voltage synchronized with the deflection. However, any shape of electrode can be applied as long as the center and side focusing forces can be differentiated.

[0039]

As described above, according to the electron gun for a color cathode ray tube of the present invention, the beam spot shapes of the three electron beams can be made uniform from the center to the left and right ends of the phosphor screen surface. It is possible to avoid deterioration of the resolution of red on the right side of the screen and deterioration of the resolution of blue on the left side of the screen. A high-quality cathode ray tube with the same R, G, and B resolutions can be used on the entire screen. Can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of an electron gun for a color cathode ray tube according to the present invention.

FIG. 2 is a perspective view of a focusing auxiliary lens of a first embodiment of a color cathode ray tube electron gun according to the present invention.

FIG. 3 is a plan view of an electron beam passage hole of the focusing auxiliary lens of the first embodiment of the electron gun for a color cathode ray tube according to the present invention.

FIG. 4 is a connection diagram of a focus voltage of the first embodiment of the electron gun for a color cathode ray tube according to the present invention.

FIG. 5 is a waveform diagram of a focus voltage in the first embodiment of the electron gun for a color cathode ray tube according to the present invention.

FIG. 6 is a plan view of an electron beam passage hole of a focusing auxiliary lens according to a second embodiment of the electron gun for a color cathode ray tube of the present invention.

FIG. 7 is a waveform diagram of a focus voltage in a second embodiment of the electron gun for a color cathode ray tube according to the present invention.

FIG. 8 is a diagram showing a dynamic focus voltage originally required for each of R, G, and B in the first and second embodiments of the electron gun for a color cathode ray tube of the present invention.

FIG. 9 is a diagram showing a state of beam spots at four corners of a screen in the first and second embodiments of the electron gun for a color cathode ray tube of the present invention.

FIG. 10 is a diagram showing a horizontal deflection magnetic field distribution and a vertical deflection magnetic field distribution generated by a self-convergence type deflection yoke.

FIG. 11 is a diagram showing a spot distortion pattern of an electron beam deflected by a self-convergence type deflection yoke.

FIG. 12 is a perspective view of a conventional electron gun for a color cathode ray tube for improving distortion of an electron beam.

FIG. 13 is a waveform diagram of a focus voltage applied in a conventional electron gun for a color cathode ray tube.

FIG. 14 is a diagram showing an effect of a quadrupole lens.

FIG. 15 is a schematic diagram showing a state of a beam spot at four corners of a screen according to a conventional technique.

FIG. 16 is a diagram showing dynamic focus voltages originally required for R, G, and B in a conventional electron gun for a color cathode ray tube.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Electron gun for color cathode ray tube 101B, 101G, 101R Cathode 102 Control electrode 103 Accelerating electrode 104a First focusing electrode (a) 104b First focusing electrode (b) 104c First focusing electrode (c) 104a1, 104a2, 104a3 First focusing Electron beam passage holes 104b1, 104b2, 104b3 of electrode (a) Electron beam passage holes 104c4, 104c5, 104c6 of first focusing electrode (b) Electron beam passage holes 104c1, 104c2, 104c3 of first focusing electrode (c) Electron beam passage hole 105 Second focusing electrode 1051, 1052, 1053 Horizontal electron beam passage hole 106 Final accelerating electrode 61, 62, 63 First focusing electrode (a), (b),
Electron beam passage holes 91, 92 Halo 10B, 10G, 10R Electron beams 101, 102 Self-convergence deflecting magnetic field 111 Beam core 112 Halo 120 Conventional electron gun 121 First focusing electrode 122 Second focusing electrode 123 Vertical electron beam Passing hole 124 Horizontal electron beam passing hole 131 Dynamic focus voltage 141 Quadrupole lens 142 Electron beam 143 Divergence force 144 Focusing force 151, 152 Halo

Claims (5)

[Claims] An electron gun for an in-line type color cathode ray tube having an electron beam generating section including a control electrode and a main lens section including a plurality of electrodes including a focusing electrode for focusing an electron beam on a phosphor screen and an accelerating electrode. The focusing electrode adjacent to the accelerating electrode is divided into a plurality of parts, and the dynamic focus voltage Ec3D and the constant focus voltage Ec3S which fluctuate in synchronization with the deflection of the electron beam.
Is applied to the plurality of focusing electrodes, and a force for focusing the electron beam in one of the horizontal direction and the vertical direction depending on which of the dynamic focus voltage Ec3D and the constant focus voltage Ec3S is a higher voltage. When the dynamic focus voltage Ec3D and the constant focus voltage Ec3S are applied to the plurality of divided electrodes, the dynamic focus voltage Ec3
A focusing auxiliary lens for generating a force for focusing the electron beam in both the horizontal and vertical directions with an increase in the voltage difference between D and the constant focus voltage Ec3S; and three horizontally arranged electrode portions constituting the focusing auxiliary lens are provided. The electron gun for a color cathode ray tube, wherein, among the electron beam passage holes, the diameter of the passage holes on both sides is the same and different from the diameter of the center passage hole. 2. The electron gun for a color cathode ray tube according to claim 1, wherein the dynamic focus voltage Ec3D and the constant focus voltage Ec3S always have a relationship of Ec3S> Ec3D, and the three horizontal portions of the electrode section constituting the focusing auxiliary lens. An electron gun for a color cathode ray tube, characterized in that, among the electron beam passage holes arranged in a row, the diameter of the passage holes on both sides is smaller than the diameter of the passage hole in the center. 3. The electron gun for a color cathode ray tube according to claim 1, wherein the dynamic focus voltage Ec3D and the constant focus voltage Ec3S are always in a relationship of Ec3S <Ec3D, and the three horizontal portions of the electrode section constituting the focusing auxiliary lens are provided. An electron gun for a color cathode ray tube, wherein the diameter of the passage holes on both sides of the electron beam passage holes arranged in the center is larger than the diameter of the passage hole in the center. 4. An electron gun for a color cathode ray tube according to claim 1, wherein when the electron lens strength of said plurality of focusing electrodes changes due to said dynamic focus voltage Ec3D, the change of the electron lens strength between the center beam and both side beams. An electron gun for a color cathode ray tube, wherein the ratio is different. 5. A color cathode ray tube equipped with the electron gun for a color cathode ray tube according to claim 1.