JP2003151461A - Cathode ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode ray tube device capable of improving resolution by preventing deterioration of a beam spot accompanied by current changes at a center part of a fluorescent screen. SOLUTION: An electron gun structure body 7 is provided with an auxiliary lens 22 preliminarily converging electron beam and a main lens focusing on the fluorescent screen 3. The electron gun structure body 7 is provided with a pre-focus lens 21 forming electron beam entering into the auxiliary lens 22 larger in a vertical direction diameter than that in a horizontal direction. The auxiliary lens 22 has relatively stronger focusing force in the vertical direction to make a diameter in the vertical direction of electron beam entering into the main lens 23 smaller than that in the horizontal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube device, and more particularly to a color cathode ray tube device adapted to stably supply good image quality.

[0002]

2. Description of the Related Art The mainstream self-convergence in-line type color cathode ray tube apparatus at present is an in-line type electron gun assembly that emits three electron beams arranged in a row passing through the same horizontal plane, and an electron beam emitted from this electron gun assembly. And a deflection yoke that generates an inhomogeneous deflection magnetic field that deflects. This deflection magnetic field is formed by a pincushion type horizontal deflection magnetic field and a barrel type vertical deflection magnetic field. As the deflection amount of the electron beam increases, the deflection magnetic field acts as a quadrupole lens equivalently for focusing the electron beam in the vertical direction and diverging in the horizontal direction.

Therefore, as shown in FIG. 6, the beam spot formed on the phosphor screen is substantially a perfect circle in the central portion, whereas the peripheral portion has a horizontally long height which is long in the horizontal direction. Luminance part (core) 50c and low-luminance part (halo) 50 extending vertically due to overfocus
with h. As a result, the resolution in the peripheral portion of the phosphor screen is greatly deteriorated.

In order to solve this problem, the prefocus lens strongly focuses the electron beam in the vertical direction rather than in the horizontal direction so that the cross-sectional shape of the electron beam incident on the deflection magnetic field is laterally long and the aberration due to the deflection magnetic field is reduced. Is now widely used.

As an example of this, FIG. 7 shows a quadra-potential type electron gun assembly. This electron gun assembly includes three cathodes K arranged in a line, and first to sixth grids G1 to G6 respectively provided with three electron beam passage holes corresponding to the three cathodes K. Have The third grid G3 is provided with a vertically elongated electron beam passage hole as shown in FIG. 8 on the surface facing the second grid G2. The other grid has electron beam passage holes of a substantially circular shape.

In this electron gun assembly, the cathode K has 150
A voltage of ~ 200V is applied. The first grid G1 is grounded. Second grid G2 and fourth grid G4
600-1000V is applied to the. A focus voltage of about 6 kV to 10 kV is applied to the third grid and the fifth grid G5. Approximately 25 kV to 3 on the 6th grid
An anode voltage of 5 kV is applied.

With such a structure of the electron gun structure, as shown in FIG. 9, the focusing force in the vertical direction is relatively strong between the second grid G2 and the third grid G3, and the negative non-focusing force is stronger than that in the horizontal direction. Prefocus lens 2 with point aberration
1, the auxiliary lens 22 is formed by the third grid G3 to the fifth grid G5, and the main lens 23 is formed between the fifth grid G5 and the sixth grid G6.

In this electron gun structure, the object point O is set at an angle α.
The electron beam emitted in 1 is strongly focused in the vertical direction than in the horizontal direction by the prefocus lens 21, and is further focused in the horizontal and vertical directions by the auxiliary lens 22. Thereafter, the electron beam is focused on the phosphor screen by the main lens 23 while maintaining the horizontally long shape. The electron beam incident on the main lens 23 in a horizontally long shape is also kept horizontally long at the deflection surface 31, and the influence of the deflection aberration is mitigated.

[0009]

As described above, the method of forming astigmatism on the prefocus lens is effective for improving the resolution in the peripheral portion of the phosphor screen. However, in the central part of the phosphor screen, there is a problem that the beam spot shape in the vertical direction is significantly deteriorated as the cathode current is increased.

That is, in the vertical direction, the electron beam is focused toward the central portion of the phosphor screen at low current and high current as shown in FIG. 11 (a). At a low current, the electron beam exits the object point O1 at a divergence angle α1. At high current, the electron beam exits from the object point O2 at a divergence angle α2. The object point O2 at high current is located closer to the phosphor screen side than the object point O1 at low current, and the divergence angle α2 at high current is larger than the divergence angle α1 at low current.

The electron beams emitted from the object points O1 and O2 are finally focused toward the phosphor screen by the prefocus lens 21, the auxiliary lens 22, and the main lens 23. At this time, the virtual object point position of the electron beam viewed from the main lens was P1V at low current, while it was shifted to P2V at the high current side toward the phosphor screen. Therefore, when the focus voltage is set so that the electron beam is just focused on the phosphor screen at a low current, the electron beam becomes underfocus at a high current. That is, when the current is high, the beam spot shape on the phosphor screen remarkably expands in the vertical direction due to the expansion due to the increase in current and the expansion due to underfocus.

Therefore, in order to just focus the electron beam on the phosphor screen at high current,
It is necessary to strengthen the focus power of the main lens. Therefore, as shown in FIG. 10, in order to always just focus the electron beam on the phosphor screen in the vertical direction as the cathode current increases,
It is necessary to increase the focus power of the main lens by lowering the focus voltage and increasing the potential difference from the anode voltage.

On the other hand, in the horizontal direction, as shown in FIG. 11B, the electron beam is focused toward the central portion of the phosphor screen at low current and high current.

At this time, the position of the virtual object point of the electron beam viewed from the main lens is P1H when the current is low, whereas it is shifted to P2H and the phosphor screen side when the current is high. As the cathode current increases, the virtual object point position shifts toward the phosphor screen in the same manner as in the vertical direction. However, the prefocus lens 2
In No. 1, the focus force in the horizontal direction is weaker than that in the vertical direction. Therefore, the horizontal diameter of the electron beam incident on the main lens 23 is larger than the vertical diameter.

Generally, when the diameter of the electron beam incident on the lens is large, the spherical aberration of the lens is likely to occur. The electron beam that has received the spherical aberration is just focused before the electron beam that has not received the spherical aberration.

Since the horizontal diameter of the electron beam incident on the main lens 23 is larger than the vertical diameter, the portion A of the main lens 23 is susceptible to spherical aberration. As a result, when the current is high, the virtual object point position seen from the main lens 23 shifts from P1H to P2H toward the main lens side, but the spherical aberration of the main lens 23 increases due to the enlargement of the electron beam diameter. Cancel the shift of the point position.

Therefore, the electron beam can be just-focused on the phosphor screen at low current and high current. Therefore, as shown in FIG. 10, in the horizontal direction, even if the cathode current increases, it is not necessary to increase the focus power of the main lens and it is not necessary to change the focus voltage.

As described above, in the vertical direction, it is necessary to change the focus voltage in order to just focus the electron beam on the phosphor screen in accordance with the change in the cathode current. In addition, the beam spot diameter at the center of the phosphor screen changes only as the cathode current increases in the horizontal direction, whereas the beam diameter only increases in the horizontal direction by increasing the current, whereas it increases in the vertical direction by increasing the current. It is remarkably enlarged due to the addition of underfocus. For this reason,
Vertical resolution is reduced.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object thereof is to prevent the deterioration of the beam spot due to the current change and improve the resolution in the central portion of the phosphor screen. It is to provide a cathode ray tube device capable of

[0020]

According to a first aspect of the present invention, a cathode ray tube device has an electron beam generating section for generating an electron beam and an electron beam generated by the electron beam generating section on a phosphor screen. A cathode ray tube device comprising: an electron gun assembly having a main lens for focusing; and a deflection yoke for generating a deflection magnetic field for deflecting an electron beam emitted from the electron gun assembly in horizontal and vertical directions, The electron gun assembly includes an auxiliary lens between the electron beam generator and the main lens, the focusing force in the vertical direction being relatively stronger than the horizontal direction, and the electron beam incident on the auxiliary lens has a vertical diameter. Is larger than the horizontal diameter, and the electron beam incident on the main lens is
The vertical diameter is smaller than the horizontal diameter.

A cathode ray tube apparatus according to the second aspect of the present invention comprises an electron beam generator for generating an electron beam, a main lens for focusing the electron beam generated by the electron beam generator on a phosphor screen. And a deflection yoke for generating a deflection magnetic field for deflecting an electron beam emitted from the electron gun assembly in a horizontal direction and a vertical direction, the electron gun assembly comprising: The auxiliary lens is provided between the electron beam generator and the main lens, and beam shaping means for shaping the vertical diameter of the electron beam incident on the auxiliary lens to be larger than the horizontal diameter. Means that the focusing force in the vertical direction is relatively stronger than that in the horizontal direction so that the vertical diameter of the electron beam incident on the main lens becomes smaller than the horizontal diameter. It is characterized in.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cathode ray tube device according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a self-convergence in-line type color cathode ray tube device as an embodiment of the cathode ray tube device includes a vacuum envelope 10. The envelope 10 has a panel 1 and a funnel 2 integrally joined to the panel 1. Panel 1
Has a phosphor screen 3 on its inner surface, which is made up of three-color phosphor layers arranged in dots or stripes that emit blue, green, and red. The shadow mask 4 has a large number of electron beam passage holes inside and is arranged so as to face the phosphor screen 3.

The in-line type electron gun assembly 7 is arranged inside the neck 5 corresponding to the small diameter portion of the funnel 2. The electron gun assembly 7 emits three electron beams 6B, 6G, 6R arranged in a row, which includes a center beam 6G passing through the same horizontal plane and a pair of side beams 6B, 6R.

The deflection yoke 8 is attached from the large-diameter portion of the funnel 2 to the neck 5. This deflection yoke 8
Are three electron beams 6B, 6 emitted from the electron gun assembly 7.
An inhomogeneous deflection magnetic field for deflecting G and 6R in the horizontal direction (H) and the vertical direction (V) is generated. This non-uniform magnetic field is formed by a pincushion type horizontal deflection magnetic field and a barrel type vertical deflection magnetic field.

The three electron beams 6B, 6G and 6R emitted from the electron gun assembly 7 are deflected by the non-uniform magnetic field generated by the deflection yoke 8, and the phosphor screen 3 is moved horizontally and vertically through the shadow mask 4. To scan. As a result, a color image is displayed.

As shown in FIG. 2, the electron gun assembly 7 has three cathodes K arranged in a line in the horizontal direction (H), and three heaters (not shown) for individually heating these cathodes K. , And 6 electrodes. Six electrodes, that is, a first grid G1, a second grid G2, a third grid G3, a fourth grid G4, a fifth grid (focus electrode) G5, and a sixth grid G6 (anode electrode).
Are sequentially arranged from the cathode K in the phosphor screen direction. The heater, the cathode K, and the plurality of electrodes are integrally supported and fixed by a pair of insulating supports (not shown).

The first grid G1 is composed of plate electrodes. As shown in FIG. 3A, this plate-shaped electrode has three electron beam passage holes arranged in a line in the horizontal direction H corresponding to the three cathodes K. These electron beam passage holes are formed in a non-circular shape having a major axis in the horizontal direction H. In this embodiment, the electron beam passage hole is formed in a rectangular shape having long sides in the horizontal direction H.

The second grid G2 is composed of plate electrodes. This plate-shaped electrode has three substantially circular electron beam passage holes arranged in a line in the horizontal direction corresponding to the three cathodes K.

The third grid G3 is composed of a cylindrical electrode having an integral structure. This cylindrical electrode has three electron beam passage holes arranged in a row in the horizontal direction corresponding to the three cathodes K on both end faces thereof. The electron beam passage hole on the end surface of the cylindrical electrode facing the second grid G2 is formed in a non-circular shape having a major axis in the horizontal direction H, as shown in FIG. In this embodiment, the electron beam passage hole is formed in a substantially rectangular shape having long sides in the horizontal direction H. In addition, the fourth of the cylindrical electrode
The electron beam passage hole on the end surface facing the grid G4 is formed in a substantially circular shape.

The fourth grid G4 is composed of a cylindrical electrode having an integral structure. The cylindrical electrode has both end surfaces, that is, an end surface facing the third grid G3 and a fifth electrode.
The end surface facing the grid G5 has three electron beam passage holes arranged in a line in the horizontal direction H corresponding to the three cathodes K. The electron beam passage holes on both end faces of this cylindrical electrode are formed in a non-circular shape having a major axis in the horizontal direction H, as shown in FIG. In this embodiment, the electron beam passage hole is formed in a substantially oval shape having a major axis in the horizontal direction H.

The fifth grid G5 is composed of a cylindrical electrode having an integral structure. The cylindrical electrode has both end surfaces, that is, an end surface facing the fourth grid G4 and a sixth electrode.
The end surface facing the grid G6 has three electron beam passage holes arranged in a line in the horizontal direction H corresponding to the three cathodes K. The electron beam passage holes on both end faces of this cylindrical electrode are formed in a substantially circular shape.

The sixth grid G6 is composed of a cylindrical electrode having an integral structure. This cylindrical electrode has three electron beams arranged in a line in the horizontal direction H corresponding to the three cathodes K on both end surfaces thereof, that is, the end surface facing the fifth grid G5 and the end surface on the phosphor screen side. It has a passage hole. The electron beam passage holes on both end faces of this cylindrical electrode are formed in a substantially circular shape.

In the electron gun assembly 7 having such a structure,
A voltage in which a video signal is superimposed on a DC voltage of about 150 to 200 V is applied to the cathode K. First grid G
1 is grounded. The second grid G2 is electrically connected to the fourth grid G4 in the pipe and has a size of about 600 to 10
A DC voltage of 00V is applied.

The third grid G3 is electrically connected to the fifth grid G5 in the tube and has a fixed voltage (focusing voltage) of a relatively medium voltage, for example, about 6 to 10 kV, regardless of the deflection amount of the electron beam. Voltage) Vf is applied.

A relatively high voltage, for example, a constant anode voltage (anode voltage) Eb at about 25 to 35 kV is applied to the sixth grid G6 regardless of the amount of deflection of the electron beam.

The electron gun assembly 7 forms an electron beam generator, an auxiliary lens, a main lens, and a beam shaping unit by applying the above-mentioned voltage to each grid.

The electron beam generator includes a cathode K, a first grid G1, a second grid G2, and a third grid G3.
Formed by. The electron beam generator generates an electron beam and forms an object point for the main lens.
Further, the electron beam generation unit includes a beam shaping unit that shapes the vertical diameter of the electron beam incident on the auxiliary lens between the first grid G1 to the third grid G3 to be larger than the horizontal diameter.

In this embodiment, the beam shaping section is formed as a prefocus lens between the second grid G2 and the third grid G3. As shown in FIG. 4, the prefocus lens 21 is a lens having a positive astigmatism in which the focusing force in the horizontal direction H is stronger than that in the vertical direction V. The prefocus lens 21 prefocuses the electron beam generated by the cathode K, the first grid G1, and the second grid G2 with a relatively weak focus force in the vertical direction V and is relatively strong in the horizontal direction H. Prefocus with focus power.

Such a prefocus lens is the first
It is formed by disposing a non-circular electron beam passage hole having a major axis in the horizontal direction H in at least one of the grids G1 to G3. In this embodiment, the second grid G3 of the third grid G3
A non-circular electron beam passage hole having a long axis in the horizontal direction H is arranged on the end surface facing 2 in FIG.

The auxiliary lens is formed by the third grid G3, the fourth grid G4 and the fifth grid G5. As shown in FIG. 4, the auxiliary lens 22 is a lens having a negative astigmatism in which the focusing force in the vertical direction V is stronger than that in the horizontal direction H. The auxiliary lens 22 pre-focuses the electron beam pre-focused by the pre-focus lens 21 in the vertical direction V with a relatively strong focus force and pre-focuses it in the horizontal direction H with a relatively weak focus force.

In this embodiment, a non-circular electron beam passage hole having a major axis in the horizontal direction H is arranged on both end faces of the fourth grid G4.

The main lens is formed by the fifth grid G5 (focus electrode) and the sixth grid G6 (anode electrode). As shown in FIG. 4, this main lens 23
Has substantially the same relatively strong focus power in both the horizontal direction H and the vertical direction V. The main lens 23 finally focuses the electron beam on the phosphor screen 3.

With such a lens structure,
It works as follows.

That is, as shown in FIG. 4, the electron beam emitted from the object point O at the divergence angle α is prefocused by the prefocus lens 21. At this time, the prefocus lens 21 has positive astigmatism. Therefore, the electron beam after passing through the prefocus lens 21 has a vertically long beam cross-sectional shape.

The vertically long electron beam emitted from the prefocus lens 21 is further prefocused by the auxiliary lens 22. At this time, the auxiliary lens 22 has negative astigmatism. Therefore, the electron beam is prefocused more strongly in the vertical direction V than in the horizontal direction H. By making the negative astigmatism component of the auxiliary lens 22 stronger than the positive astigmatism component of the prefocus lens 21, the electron beam after passing through the auxiliary lens 22 has a laterally long beam cross-sectional shape.

The horizontally long electron beam emitted from the auxiliary lens 22 is finally passed through the main lens 23 to finally form the phosphor screen 3.
Focused on. At this time, the electron beam emitted from the main lens 23 passes through the deflection surface 31 in a state where the beam cross-sectional shape is further elongated and the incident angles in the horizontal direction H and the vertical direction V on the phosphor screen 3 are αiH, respectively. , And α iV.

In the electron gun assembly having such a lens structure, as shown in FIG. 4, the lens main surface 32 in the vertical direction V is used.
The position of is located closer to the object point O than the position of the lens main surface 33 in the horizontal direction H. That is, since the incident angle on the phosphor screen 3 is αiH> αiV, the horizontal lens magnification (Mh = α / αiH) is smaller than the vertical lens magnification (Mv = α / αiV). That is, in the central portion of the phosphor screen 3, the beam spot diameter is smaller in the horizontal direction V than in the vertical direction H.

Therefore, in this embodiment, the cathode K
In the electron emission region for generating the electron beam in, the horizontal direction H is larger than the vertical direction V. That is, the electron beam passage hole of the first grid G1 has a horizontally long shape having a long axis in the horizontal direction H. As a result, the object point diameter in the vertical direction V is reduced from that in the horizontal direction H, and the object point becomes horizontally long. Therefore, it is possible to form a substantially circular beam spot at the center of the phosphor screen.

Further, in the electron gun assembly having the above-described structure, the electron beam is always substantially just in the horizontal direction H and the vertical direction V on the phosphor screen even if the focus voltage is substantially constant with respect to the change of the cathode current. It becomes possible to focus. The reason will be described below.

That is, FIG. 5A shows an optical lens model in the vertical direction of the electron gun assembly according to this embodiment, in which the upper half shows a low current and the lower half shows a high current. Shown respectively. In addition, FIG.
It shows an optical lens model in the horizontal direction, and the upper half shows a low current and the lower half shows a high current.

First, the vertical direction will be described.

As shown in FIG. 5A, the electron beam emits the object point O3V at a divergence angle α3V when the current is low. Also, the electron beam is
The object point O4V is emitted at a divergence angle α4V. The object point O4V at high current is located closer to the phosphor screen side than the object point O3V at low current, and the divergence angle α4V at high current is larger than the divergence angle α3V at low current.

The electron beams emitted from the object points O3V and O4V enter the prefocus lens 21 having positive astigmatism. Therefore, the prefocus lens 2
The electron beam that has passed through 1 is incident on the auxiliary lens 22 having a vertically long beam cross-sectional shape and having negative astigmatism.

Since the electron beam incident on the auxiliary lens 22 has a vertically long sectional shape, and the auxiliary lens 22 has a negative astigmatism in which the focusing force in the vertical direction V is stronger than that in the horizontal direction H, Is affected by spherical aberration at the B portion of the auxiliary lens 22 at high current. The electron beam that has passed through the portion B of the auxiliary lens 22 is focused with a strong focus force due to spherical aberration. Therefore, the virtual object point position viewed from the main lens 23 is P3V when the current is low.
Therefore, even at high current, P4V is at a position close to P3V.

As described above, compared with the conventional example shown in FIG. 11A, according to this embodiment, the virtual object point position in the vertical direction V can be changed even at low current and high current. The difference is reduced to almost equal positions. Therefore, even if the focus voltage is set so that the electron beam is just focused on the phosphor screen at a low current, the electron beam is just focused on the phosphor screen at a high current at substantially the same level of focus voltage. It becomes possible to do.

Therefore, in the central portion of the phosphor screen, the electron beam can always be just-focused in the vertical direction irrespective of the change in current, and the expansion of the beam spot diameter due to the increase in current can be suppressed.

Next, the horizontal direction will be described.

That is, as shown in FIG. 5B, at a low current, the electron beam emits the object point O3H at the divergence angle α3H. Further, at the time of high current, the electron beam emits the object point O4H at the divergence angle α4H. The object point O4H at high current is located closer to the phosphor screen side than the object point O3H at low current, and the divergence angle α4H at high current is further.
Is larger than the divergence angle α3H at low current.

The electron beams emitted from the object points O3H and O4H enter the prefocus lens 21 having positive astigmatism. Therefore, the prefocus lens 2
The electron beam that has passed through 1 is incident on the auxiliary lens 22 having a vertically long beam cross-sectional shape and having negative astigmatism.

Since the cross-sectional shape of the electron beam incident on the auxiliary lens is vertically long, the electron beam is incident on the auxiliary lens 2
At 2, the spherical aberration is hardly affected in the horizontal direction H.
Therefore, the virtual object point position of the electron beam viewed from the main lens 23 is P3H when the current is low, whereas it is shifted to P4H and the phosphor screen side when the current is high. As the cathode current increases, the virtual object point position shifts toward the phosphor screen.

However, since the focusing force in the horizontal direction H of the auxiliary lens 22 is weaker than that in the vertical direction V, the main lens 23
The horizontal diameter of the electron beam incident on is larger than the vertical diameter. Therefore, at a high current, the electron beam is affected by the spherical aberration at the C portion of the main lens 23.
As a result, when the current is high, the virtual object point position seen from the main lens 23 shifts from P3H to P4H toward the main lens side, but the spherical aberration of the main lens 23 increases due to the enlargement of the electron beam diameter. Cancel the shift of the point position.

Therefore, even when the focus voltage is set so that the electron beam is just focused on the phosphor screen at the low current, the electron beam is made to have the focus voltage at the substantially same level at the high current. It becomes possible to just focus on.

Therefore, in the central portion of the phosphor screen, the electron beam can always be just-focused in the horizontal direction H as well as in the vertical direction V irrespective of the change in current, and the expansion of the beam spot diameter due to the increase in current can be suppressed. It becomes possible.

As described above, in the peripheral portion of the phosphor screen, the beam spot is formed on the main lens 23 by the electron beam having the horizontally long beam cross-sectional shape, so that the influence of the deflection aberration is mitigated and the beam spot is substantially round. It is possible to form the shape. Further, in the central portion of the phosphor screen, the shape of the electron beam incident on the deflecting surface and the main lens is horizontally elongated, and even if the focus voltage is substantially constant with respect to the change in current, the electron beam is directed in the horizontal and vertical directions. It is possible to just focus on the screen, and it is possible to reduce the expansion of the vertical diameter of the beam spot at high current.

This makes it possible to form a good beam spot on the entire screen. Moreover, since the beam spot size can be sufficiently reduced and made uniform, the display quality can be improved and the resolution can be improved.

As described above, according to the cathode ray tube device of the embodiment of the present invention, the electron beam incident on the auxiliary lens has a vertically long beam cross-sectional shape. Therefore, as the current increases, the electron beam diameter increases, and in the vertical direction, the electron beam is strongly affected by the spherical aberration by the auxiliary lens. By utilizing the spherical aberration of this auxiliary lens, the fluctuation of the virtual object point position in the vertical direction seen from the main lens positioned next to the auxiliary lens is reduced due to the increase in current. As a result, even when the current changes, it is possible to just focus the electron beam on the phosphor screen in the vertical direction with the focus voltage kept substantially constant. Therefore, it is possible to suppress the expansion of the beam spot diameter in the vertical direction due to the increase in current.

Further, since the vertical focusing force of the auxiliary lens is stronger than that in the horizontal direction, the vertical diameter of the beam spot may be deteriorated. Therefore, by making the electron emission region of the cathode smaller in the vertical direction than in the horizontal direction,
The object point diameter in the vertical direction is reduced, and deterioration in the vertical diameter of the beam spot is suppressed.

Further, in the horizontal direction, the electron beam incident on the main lens has a horizontally long shape, is affected by the spherical aberration of the main lens, and is just focused at a substantially constant focus voltage.

Further, since the shape of the electron beam incident on the main lens is horizontally long, the shape of the electron beam incident on the deflection magnetic field is also horizontally long, and the deflection aberration can be suppressed as in the conventional case.

In the above-described embodiment, the beam shaping section for shaping the electron beam having the vertically long beam cross-sectional shape is formed between the second grid and the third grid, but the present invention is not limited to this. Instead, it is possible to form between the first grid and the second grid by appropriately setting the shape of the electron beam passage holes formed in the first grid to the third grid and the voltage applied to each grid. However, it is possible to form the entire first to third grids.

[0072]

As described above, according to the present invention, there is provided a cathode ray tube device capable of preventing the deterioration of the beam spot due to the current change and improving the resolution in the central portion of the phosphor screen. be able to.

[Brief description of drawings]

FIG. 1 is a horizontal sectional view schematically showing a configuration of a color cathode ray tube device according to an embodiment of the present invention.

FIG. 2 is a horizontal cross-sectional view schematically showing an example of the configuration of an electron gun assembly applied to the cathode ray tube device shown in FIG.

3 (a) is a front view schematically showing a structure of a first grid applied to the electron gun assembly shown in FIG. 1, and FIG. 3 (b) is a third grid. FIG. 4C is a front view schematically showing the structure of the end surface facing the second grid, and FIG. 3C is a front view schematically showing the structure of both end surfaces of the fourth grid.

4 is a diagram showing an optical lens model in a vertical direction and a horizontal direction of the electron gun assembly shown in FIG.

5A shows an optical lens model in the vertical direction of the electron gun assembly shown in FIG.
FIG. 5B shows an optical lens model in the horizontal direction.

FIG. 6 is a diagram showing an example of a beam spot formed on a phosphor screen in a conventional electron gun assembly.

FIG. 7 is a diagram schematically showing a configuration of a conventional electron gun assembly.

8 is a front view schematically showing a structure of a surface of a third grid, which is applied to the electron gun assembly shown in FIG. 7, and faces a second grid.

9 is a diagram showing an optical lens model in a vertical direction and a horizontal direction of the electron gun assembly shown in FIG.

FIG. 10 is a diagram showing a relationship between a cathode current and a focus voltage in a conventional electron gun assembly.

11A shows an optical lens model in the vertical direction of the electron gun assembly shown in FIG. 7, and FIG. 11B shows an optical lens model in the horizontal direction. It is a thing.

[Explanation of symbols]

1 ... panel 2 ... Funnel 3 ... Phosphor screen 4 ... Shadow mask 5 ... neck 6 (R, G, B) ... electron beam 7 ... Electron gun structure 8 ... Deflection yoke 21 ... Prefocus lens 22 ... Auxiliary lens 23 ... Main lens K (R, G, B) ... Cathode G1 ... 1st grid G2 ... Second grid G3 ... 3rd grid G4 ... 4th grid G5 ... Fifth grid G6 ... 6th grid

Claims (6)

[Claims] 1. An electron gun assembly having an electron beam generator for generating an electron beam and a main lens for focusing the electron beam generated by the electron beam generator onto a phosphor screen, and an electron gun assembly. A cathode ray tube device including a deflection yoke that generates a deflection magnetic field for deflecting an electron beam emitted from the electron beam in a horizontal direction and a vertical direction, wherein the electron gun structure includes a portion between the electron beam generator and the main lens. And an auxiliary lens having a relatively stronger vertical focusing force than the horizontal direction, and the electron beam incident on the auxiliary lens has a vertical diameter larger than the horizontal diameter and an electron beam incident on the main lens. Is a cathode ray tube device having a vertical diameter smaller than the horizontal diameter. 2. An electron gun assembly having an electron beam generator for generating an electron beam and a main lens for focusing the electron beam generated by the electron beam generator onto a phosphor screen, and an electron gun assembly. A cathode ray tube device including a deflection yoke that generates a deflection magnetic field for deflecting an electron beam emitted from the electron beam in a horizontal direction and a vertical direction, wherein the electron gun structure includes a portion between the electron beam generator and the main lens. And a beam shaping means for shaping the vertical diameter of the electron beam incident on the auxiliary lens to be larger than the horizontal diameter of the electron beam, wherein the auxiliary lens of the electron beam incident on the main lens. A cathode ray tube device characterized in that the focusing force in the vertical direction is relatively stronger than that in the horizontal direction so that the diameter in the vertical direction becomes smaller than that in the horizontal direction. 3. The cathode ray tube apparatus according to claim 2, wherein the electron beam generating section includes the beam shaping means. 4. The electron beam generator includes first to third grids, the first grid is grounded, a voltage having a predetermined potential is applied to the second grid, and the third grid is provided with the voltage. The cathode ray tube device according to claim 3, wherein a voltage higher than a predetermined potential is applied. 5. The cathode ray tube apparatus according to claim 3, wherein a region in which the electron beam is generated on the cathode has a horizontal direction larger than a vertical direction. 6. The cathode ray tube device according to claim 5, wherein the first grid disposed adjacent to the cathode has a non-circular electron beam passage hole having a major axis in the horizontal direction. .