JPH10172462A - Electron gun for color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a focus lens diameter in a vertical direction, and improve assemblage precision and reduce cost in manufacturing in an electron gun for a color cathode-ray tube. SOLUTION: Among electron beam passage holes 60R, 60G, 60B end 61R, 61G, 61B in both a low pressure side electrode 55 and a high pressure side electrode 56 to compose a focus lens in an electron gun, the electron beam passage holes 60R, 60B and 61R, 61B on both sides ere formed of concentric circles cut by vertical line segments to be ovals, and the electron beam passage holes 61R, 61B on both sides of the high pressure side electrode 56 are formed to have aperture parts 62 on the outer side of the electron beam passage holes 60R, 60B on both sides of the low pressure side electrode 55.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electron gun for a color cathode ray tube.

[0002]

2. Description of the Related Art FIG. 6 shows an example of an electron gun generally used widely. The electron gun 1, the red, green, three cathodes K _R corresponding to the blue, K _G and K _B are line arrangement, the three cathodes K _R, so that common to K _G and K _B , The first electrode 11 and the second electrode 1 on the same axis.
2, a third electrode 13, a fourth electrode 14, a fifth electrode (focus electrode) 15, a sixth electrode (anode electrode) 16, and a shield cup 17 at the last stage are sequentially arranged, and a uni-bipotential lens type three-beam single An electron gun is configured.
Each of the first electrode 11, the second electrode 12, the third electrode 13, the fourth electrode 14, the fifth electrode 15, and the sixth electrode 16 has an electron beam transmitting hole through which each of the electron beams _BR , _BG, and _BB passes. Is provided. The same potential is applied to the second electrode 12 and the fourth electrode 14, the focus voltage Vf (for example, about 6 KV to 10 KV) is applied to the third electrode 13 and the fifth electrode 15,
An anode voltage VH (for example, about 27 KV) is applied to the electrode 16.

In this electron gun 1, the cathodes K _R , K _G ,
K _B, generated by the first and second electrodes 11 and 12, each of the electron beams B _R is controlled, B _G and B _B is the third electrode 1
3, fourth electrode 14 and fifth electrode (focus electrode) 15
After the divergence angle is adjusted by the pre-stage electron lens (pre-stage focus lens) formed by the above, a main electron lens (main focus lens) composed of the fifth electrode (focus electrode) 15 and the sixth electrode (anode electrode) 16 Is converged.

[0004] As shown the electron gun 1 in Figure 7, is disposed in a neck portion of the cathode ray tube 21 by the glass bulb, an electron beam B is converged by the electron gun 1 _R, B _G, fluorescent surface 22 B _B A color cathode ray tube 23 that converges to form a spot is formed thereon. Reference numeral 24 denotes a deflection yoke.

Conventionally, in a color cathode ray tube 23, red,
Green, in order to converge the three electron beams to the screen center of the blue electron beam B _R of each of the fifth electrode 15 and sixth electrode 16 constituting the main electron lens of the electron gun 1 described above, B _G, and Electron beam transmission hole 31 through which B _B passes
As shown in FIG. 8, R, 31G, 31B and 32R, 32G, 32B are formed in perfect circles and have high-voltage side electrodes, that is, electron beam transmission holes 32 on both sides of the sixth electrode 16.
A method is widely used in which R and 32B are decentered outside the low-voltage side electrodes, that is, outside the electron beam transmission holes 31R and 31B on both sides of the fifth electrode 15. In this case, a pair of inner core pins 35 used for manufacturing the electron gun also need to be eccentric as shown in FIGS. 9A and 9B.

[0006]

By the way, assembling accuracy of the electron gun is required to be approximately 10 μm, but there is a problem that the assembling accuracy of the inner core pin 35 itself is several μm. In addition to the cost of the eccentric inner core pin 35 itself, frequently checking the dimensions of the eccentric inner core pin 35 during production increases the cost of the product itself.

In recent years, the demand for resolution for color cathode ray tubes has been increasing more and more. A major factor that determines the resolution is the beam spot diameter on the screen (phosphor screen). For this reason, it is necessary to narrow down the beam spot of the electron gun, which greatly affects the resolution, as small as possible. The beam spot diameter is usually represented by the formula [Equation 1].

[0008]

## EQU1 ## Beam spot diameter = ｛(M × d + ／ × M ×
C _S × θ ³ ) ² + Rep ² ｝ ^1/2 where M: image magnification d: virtual object point diameter C _S : spherical aberration coefficient θ: divergence angle Rep: electron repulsion

Here, the lens diameter of the electron gun 1 is enlarged,
Although it is very effective to reduce the spherical aberration coefficient C _S , the size of the lens aperture is determined by the restriction on the neck diameter of the cathode ray tube 25. For example, inner diameter 29.1
In the case of a neck of mm, the lens aperture of about 6.2 mm is the limit.

In view of the above, the present invention makes it possible to use a concentric inner core pin in manufacturing, improve the assembly system, reduce costs, and make it possible to increase the diameter of the focus lens in the vertical direction. It is an object of the present invention to provide a color cathode ray tube electron gun capable of realizing a cathode ray tube having a high resolution.

[0011]

In the electron gun for a color cathode ray tube according to the present invention, the electron beam transmitting holes on both sides of the electron beam transmitting holes of both the low voltage side electrode and the high voltage side electrode constituting the focus lens are the same. It is formed as an ellipse obtained by cutting the core circle by a vertical line segment, and the electron beam transmitting holes on both sides of the high voltage side electrode have an opening outside the electron beam transmitting holes on both sides of the low voltage side electrode. .

According to this configuration, the electron beam transmission holes on both sides of the high-voltage side electrode and the low-voltage side electrode are formed into an oval shape obtained by cutting a concentric circle by a vertical line, thereby increasing the vertical lens diameter. In addition, since the concentric inner core pins can be used at the time of manufacturing, the assembling accuracy is improved. Since the electron beam transmitting holes on both sides of the high voltage side electrode have openings outside the electron beam transmitting holes on both sides of the low voltage side electrode, convergence of a plurality of electron beams is established.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an electron gun for a color cathode ray tube according to the present invention, the electron beam transmitting holes on both sides of the electron beam transmitting holes of both the low voltage side electrode and the high voltage side electrode constituting the focus lens are concentric circles. And a configuration in which the electron beam transmission holes on both sides of the high voltage side electrode have openings outside the electron beam transmission holes on both sides of the low voltage side electrode. I do.

The electron beam transmission holes on both sides of the high voltage side electrode are:
It is possible to have a shape in which only the inside is cut by a vertical line segment.

The electron beam transmission hole at the center of the low voltage side electrode and the high voltage side electrode can be formed as a perfect circle or a vertically long ellipse.

The electron beam transmission hole at the center between the low-voltage side electrode and the high-voltage side electrode can be formed as an ellipse obtained by cutting a concentric circle by a vertical line segment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of an electron gun for a color cathode ray tube according to the present invention. The electron gun 41 in the same manner as described above, red, green, three cathodes K _R corresponding to blue, K _G and K _B are line arrangement, the three cathodes K _R, with respect to K _G and K _B The first electrode 51, the second electrode 52, the third electrode 53, the fourth electrode 54, the fifth electrode (focus electrode) 55, the sixth electrode (anode electrode) 56, and the Shield cup 57
Are sequentially arranged, and the uni-bipotential lens type 3
A beam single electron gun is configured. Each of the first electrode 51, the second electrode 52, the third electrode 53, the fourth electrode 54, the fifth electrode 55 and the sixth electrode 56 has a corresponding one of the electron beams _BR , _BG and _BB.
There is provided an electron beam transmission hole through which the light passes. The same potential is applied to the second electrode 52 and the fourth electrode 54, and the third electrode 5
The focus voltage Vf is applied to the third and fifth electrodes 55, and the anode voltage VH is applied to the sixth electrode 56.

Here, an example of the voltage of each of the electrodes 51 to 56 is shown. The voltage of the first electrode 51 is about 0 V. The voltage of the second electrode 52 and the fourth electrode 54 is about 500 V. The voltage Vf of the third electrode 53 and the fifth electrode 55 is about 6 kV to 10 kV. The voltage HV of the sixth electrode 56 is about 27 kV. , cathode _{K R, K G, K B} , first
Generated by the electrode 51 and the second electrode 52, the electron beams B _R is controlled, B _G and B _B is the third electrode 53, front electronic lens formed by the fourth electrode 54 and the fifth electrode (focus electrode) 55 After the divergence angle is adjusted by the (first focus lens), the fifth electrode (focus electrode) 5
The light is converged by a main electron lens (main focus lens) composed of fifth and sixth electrodes (anode electrodes) 56. FIGS. 2 to 4 show an embodiment of the electron gun 41 of FIG. 1, particularly, the electron beam transmission holes of the fifth electrode 55 and the sixth electrode 56 constituting the main electron lens (main focus lens).

In the embodiment shown in FIG. 2, the three electron beam transmitting holes 60R and 61R, 60R, 60G and 61G of the fifth electrode 55 and the sixth electrode 56 are opposed to each other.
60B and 61B are each formed by an ellipse obtained by cutting a concentric circle by a vertical line segment, and the electron beam transmitting holes 61R and 61B on both sides of the sixth electrode 56 are respectively formed by the electron beam transmitting holes on both sides of the fifth electrode 55. It is formed in a shape having openings 62 shifted by distances d _1a and d _1b (d _1a may be equal to or different from d _1b ) outside of 60R and 60B.

As described above, the electron beam transmitting holes 61R and 61B on both sides of the sixth electrode 56 have the shape of the opening 62 shifted to the outside of the electron beam transmitting holes 60R and 60B on both sides of the fifth electrode 55. Thereby, the convergence of the three electron beams B _R , B _G , and B _B is established.

The electron beam transmitting holes 60R and 61R on at least both sides of the fifth electrode 55 and the sixth electrode 56,
Since 60B and 61B are ellipses obtained by cutting concentric circles by vertical line segments, the concentric inner core pins 65 shown in FIG. 5 can be used. Therefore, it is not necessary to use an eccentric inner pin at the time of manufacturing, and the assembling accuracy is improved and the cost can be reduced. Also, the electron beam transmitting holes 60R to 60R
B, since 61R~61B is oblong in the vertical direction, the vertical direction, than the conventional large lens aperture (approximately 1.5 times) is constructed, can be reduced spherical aberration coefficient C _S. Therefore, a high-resolution color cathode ray tube can be realized.

In the embodiment shown in FIG. 3, the electron beam transmitting holes 60G and 61G at the center of the fifth electrode 55 and the sixth electrode 56 are vertically elliptical, and the electron beam transmitting holes 60R and 60R on the other sides are formed.
B and 61R and 61B are formed as ellipses obtained by cutting concentric circles by vertical line segments as in FIG. Since the method of passing the concentric inner core pin 65 shown in FIG. 5 through the electron beam transmitting holes 60R and 61R, 60B and 61B on both sides is used for assembling the electron gun, as shown in FIG. 60G and 61G may be oval shapes.
The embodiment of FIG. 3 has the same operation and effect as the embodiment of FIG.

The embodiment shown in FIG. 4 shows the electron beam transmitting holes 60R, 60G,
Although 60B and 61R, 61G, and 61B have concentric circles cut by vertical segments, the center electron beam transmitting hole 6
0G and 61G are oval with both sides cut by vertical line segments,
Electron beam transmission holes 60R, 60B on both sides of fifth electrode 55
Is an ellipse obtained by cutting the inner and outer sides of the circle with vertical lines, and the electron beam transmitting holes 61R and 61B on both sides of the sixth electrode 56 are not ellipses cut by two vertical lines, but the inner side of the circle. Only the fifth electrode 55 is cut by a vertical line segment, and has an opening 63 that bulges outside the electron beam transmitting holes 60R and 60B on both sides of the fifth electrode 55. That is, in this case, the sixth
The inner edges of the electron beam transmitting holes 61R and 61B on both sides of the electrode 56 are connected to the electron beam transmitting holes 60R and 60R on both sides of the fifth electrode 55.
Coincides with the inner edge of 60B.

In this embodiment, the same operation and effect as those of the embodiment shown in FIG. 2 are obtained. In the configuration of FIG.
The central electron beam transmission holes 60R and 60B may have a vertically long elliptical shape as shown in FIG.

FIGS. 2 to 4 show a main electron lens (main focus lens) composed of a fifth electrode 55 and a sixth electrode 56.
Although the present invention has been described on the side of, the present invention can also be applied to a front-stage electronic lens (front-stage focus lens) including the third electrode 53, the fourth electrode, and the fifth electrode 55. For example, the convergence can be performed by forming the electron beam transmitting holes at the portions where the fourth electrode 54 and the fifth electrode 55 face each other as shown in FIGS.

Although the electron gun of the uni-bipotential lens system as shown in FIG. 1 has been described as a representative example, a bi-potential lens, a uni-potential lens, a tri-potential lens, the fifth electrode (focus electrode) 55 in FIG.
A uni-bipotential lens system in which an intermediate electrode to which an intermediate voltage Vm of the focus voltage Vf and the anode voltage HV is applied between the first electrode and the sixth electrode (anode electrode) 56 to add an electric field expansion lens with a gentle axial potential is added. It is needless to say that the present method shown in FIGS. 2 to 4 can be applied to a focus lens portion of an electron gun of a compound lens type.

[0028]

According to the present invention, of the electron beam transmitting holes of both the low voltage side electrode and the high voltage side electrode constituting the focus lens in the electron gun, the electron beam transmitting holes on both sides form a concentric circle by a vertical line segment. The vertical focus lens is formed by forming an elliptical shape cut in step 2 and making the electron beam transmission holes on both sides of the high voltage side electrode an opening outside the electron beam transmission holes on both sides of the low voltage side electrode. The diameter can be increased, and a high-resolution cathode ray tube can be realized. In manufacturing, concentric inner core pins can be used, and assembling accuracy is improved. Further, since it is not necessary to use an eccentric core pin, the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of an electron gun for a color cathode ray tube according to the present invention.

FIG. 2 is a configuration diagram showing an example of electron beam transmission holes of a low-voltage side electrode and a high-voltage side electrode constituting a focus lens of the electron gun according to the present invention.

FIG. 3 is a configuration diagram showing another example of the electron beam transmission holes of the low-voltage side electrode and the high-voltage side electrode that constitute the focus lens of the electron gun according to the present invention.

FIG. 4 is a configuration diagram showing another example of the electron beam transmission holes of the low-voltage side electrode and the high-voltage side electrode constituting the focus lens of the electron gun according to the present invention.

FIG. 5 is a configuration diagram showing an example of a concentric inner core pin used for assembling an electron gun.

FIG. 6 is a configuration diagram of an electron gun of a uni-bipotential lens system.

FIG. 7 is a configuration diagram of a color cathode ray tube.

8 is a configuration diagram showing a conventional example of electron beam transmission holes of a low voltage side electrode and a high voltage side electrode constituting a focus lens in the electron gun of FIG.

FIG. 9A is a configuration diagram of an inner core pin used for assembling a conventional electron gun. B is a cross-sectional view taken along line AA of FIG. 9A.

[Explanation of symbols]

41 an electron gun for a color cathode ray tube, 51 to 56 first to sixth electrodes, 57 a shield _{cup, K R, K G, K} B cathode, 60R, 60G, 60B, 61R , 61G, 61
B Electron beam transmission hole

Claims (6)

[Claims] 1. An electron beam transmitting hole on both sides of an electron beam transmitting hole of both a low voltage side electrode and a high voltage side electrode forming a focus lens is formed by an ellipse obtained by cutting a concentric circle by a vertical line segment, An electron gun for a color cathode ray tube, wherein the electron beam transmitting holes on both sides of the high voltage side electrode have an opening outside the electron beam transmitting holes on both sides of the low voltage side electrode. 2. The electron gun for a color cathode ray tube according to claim 1, wherein the electron beam transmission holes on both sides of the high-voltage side electrode have a shape in which only the inside is cut by a vertical line segment. 3. The electron gun for a color cathode ray tube according to claim 1, wherein an electron beam transmission hole at the center of the low-voltage side electrode and the high-voltage side electrode is formed as a perfect circle or a vertically long ellipse. 4. An electron gun for a color cathode ray tube according to claim 2, wherein an electron beam transmission hole at the center of said low voltage side electrode and said high voltage side electrode is formed as a perfect circle or a vertically long ellipse. 5. The collar according to claim 1, wherein an electron beam transmission hole at the center of the low-voltage side electrode and the high-voltage side electrode is formed by an ellipse obtained by cutting a concentric circle by a vertical line segment. Electron gun for cathode ray tube. 6. The collar according to claim 2, wherein an electron beam transmission hole at the center between the low-voltage side electrode and the high-voltage side electrode is formed by an ellipse obtained by cutting a concentric circle by a vertical line segment. Electron gun for cathode ray tube.