JPH07142000A - Cathode-ray tube - Google Patents

Abstract

(57) [Abstract] [Purpose] The focus characteristics can be improved in the entire current range of the electron beam, and good resolution can be obtained.
Provided is a cathode ray tube including an electron gun configured to reduce moire in a small current region. An anode electrode having an internal electrode for focusing control so as to have a plurality of electron beam passage openings facing the focusing electrode 95.
The main lens is composed of 96, is connected to the anode electrode 96 coaxially with the electron gun using a plurality of electron beams in an in-line arrangement, and is installed between the fluorescent screen and the electron gun to position the electron gun in the vacuum envelope. An opening 97-1 ′ having a diameter substantially the same as the diameter of the anode electrode 96 on the phosphor screen side is provided in the anode side bottom portion 97-1 of the cylindrical electrode part 97 for attaching a member for mounting.

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, and more particularly, to a cathode ray tube having an electron gun capable of improving a focus characteristic over the entire phosphor screen and in the entire current region of an electron beam to obtain a good resolution. Regarding

[0002]

2. Description of the Related Art A color cathode ray tube having a plurality of in-line arranged electron beams is widely used as an image display means of a television receiver or a monitor terminal.

FIG. 5 is a sectional view for explaining the structure of a shadow mask type color cathode ray tube as an example of the color cathode ray tube, wherein 1 is a panel portion which constitutes an image screen, 2 is a neck portion which houses an electron gun, 3 is a funnel portion connecting the panel portion and the neck portion, 4 is a fluorescent surface formed on the inner surface of the panel portion, 5 is a shadow mask, 6 is a mask frame for holding the shadow mask, and 7 is a magnetic shield for shielding an external magnetic field. , 8 is a suspension spring, 9 is an in-line type electron gun, 10 is a deflecting device, 11 is a dental ring / purity magnet, B _C is a center electron beam, and B _S is a side electron beam.

In FIG. 1, a color cathode ray tube of this type has a panel portion 1 having a phosphor screen 4 formed on the inner surface thereof and an electron gun 9.
A vacuum envelope is formed from a neck portion 2 for accommodating the above and a funnel portion 3 connecting the panel portion and the neck portion.

The electron gun housed in the neck portion has a plurality of electrodes such as a cathode, a control electrode, a focusing electrode, and an anode electrode facing the focusing electrode. The focusing lens and the anode electrode form a main lens. A plurality of electron beams that are configured and arranged in-line are emitted toward the phosphor screen 4.

The deflection device provided in the transition region between the funnel portion and the neck portion of the vacuum envelope deflects the three electron beams emitted from the electron gun 9 in both the horizontal and vertical directions of the fluorescent screen 4 to generate shadows. A color image is formed by receiving color selection by the mask 5 and striking the phosphor screen 4.

The shadow mask 5 is welded and fixed to the mask frame 6, and a suspension spring 8 fixed to a part of the outer periphery of the mask frame 6 is locked to a panel pin embedded in the inner wall of the panel 1 to cause fluorescence. It is mounted at a predetermined distance from the surface 4.

FIG. 6 is a side view for explaining an example of an electron gun housed in the neck portion of a color cathode ray tube. K is a cathode, 91 is a first electrode, 92 is a second electrode, and 93 is a third electrode. , 94 is a fourth electrode, 95 is a fifth electrode, 96 is a sixth electrode, 97 is a cylindrical electrode, 98 is bead glass, and 99 is a stem.

In the figure, the first electrode 91 to the fourth electrode 9
The control and prefocusing are performed by means of 4, and the main lens is constituted by the fifth electrode 95 which is the focusing electrode and the sixth electrode 96 which is the anode electrode.

Further, the cylindrical electrode 97 is a so-called cup electrode, is connected to the anode electrode 6 (sixth electrode) to shield the deflection magnetic field, and a contact spring for positioning the electron gun on the inner wall of the neck portion. An electrode component for fixing a getter or the like is constructed.

In addition to the above-mentioned type, in addition to the above electron gun, it has a cathode, a first electrode, a second electrode, a third electrode, a fourth electrode and a cylindrical electrode, and the second electrode and the third electrode. In addition, there are various types in which the main lens is configured.

FIG. 7 is a side sectional view of an essential part for explaining the electrode structure around the main lens in the conventional electron gun, and FIG. 8 is FIG.
It is the top view seen from the AA direction.

In FIG. 7, an anode electrode 96 is connected to the cylindrical electrode 97, and an internal electrode 96-1 for focusing control having a plurality of electron beam passage openings is provided inside the anode electrode 96. At the bottom portion 97-1 of the cylindrical electrode 97, three circular electron beam passage openings 9 are arranged in the in-line arrangement direction.
7a, 97b, 97c are provided. In addition, the electron beam passage openings 97a, 97b, and
As shown in FIG. 8, it is formed to be long (longitudinal) in a direction perpendicular to the in-line arranging direction so as to be aligned with 97c.
1 and electron beam passage ports a, b, c formed by the inner wall of the anode
Is provided.

The main lens is formed at the facing portion of the focusing electrode 95 and the anode 96, and its electric field is distributed from the internal electrode 96-1 to the bottom portion of the cylindrical electrode 97 as shown in FIG.

In this type of electron gun, as a means for obtaining a good reproduced image from the central portion to the peripheral portion of the phosphor screen, for example, in the area of the electrodes (second electrode and third electrode) forming the focusing lens. Which is provided with an astigmatism lens (Japanese Patent Laid-Open No. 53-18866), an electrode which constitutes a prefocus lens of an in-line three-beam electron gun (first
Electron beam passage openings of the electrode and the second electrode are vertically long, the shape of each electrode is different, and the aspect ratio of the center electron gun is smaller than that of the side electron gun (Japanese Patent Laid-Open No. 51-
No. 64368), a non-rotationally symmetric lens is formed by a slit formed on the cathode side of the third electrode of an in-line array electron gun, and the depth of the slit in the axial direction of the electron gun is smaller in the center electron beam than in the side electron beam. A method in which an electron beam is projected onto a phosphor screen through at least one deep, non-rotationally symmetric lens (Japanese Patent Laid-Open No. 60-81736).
Are known.

The above-mentioned conventional electrodes (first electrode, second electrode, ...) Refer to the electrodes described in the respective publications.

[0017]

The requirement for focus characteristics in a cathode ray tube is that the resolution is good in the entire area of the screen composed of the fluorescent screen and in the entire current range of the electron beam.
In addition, moire does not occur in the low current region, and the resolution of the entire screen is uniform in the entire current region.

Designing an electron gun that simultaneously satisfies such a plurality of required characteristics requires a high level of technology.

According to the research conducted by the present inventors, it is indispensable to provide an electron gun having a combination of a lens with astigmatism and a large-diameter main lens in order to provide the cathode ray tube with the above-mentioned various characteristics. It turned out that

However, there is a limit to the cross-sectional size of the neck portion from the viewpoint of the power consumption for generating the deflection magnetic field in the inner diameter of the vacuum envelope accommodating the electron gun, and the outer diameter of the large-diameter main lens is as described above. Limited by limits.

In the above-mentioned prior art, the limit structure for substantially enlarging the aperture of the main lens is not taken into consideration under the above restrictions.

Further, in the above-mentioned prior art, no consideration has been given to a structure which simplifies the production of electrode parts constituting a large-diameter main lens.

In the electron gun shown in FIG. 6, the influence of the electric field on the electron beam by the length of each electrode, the diameter of the electron beam passage opening, etc., is different. For example, the shape of the electron beam passage opening of the first electrode 91 close to the cathode K influences the spot shape of the electron beam in the small current area, but the shape of the electron beam passage opening of the second electrode 92 is large in the small current area. It affects the spot shape of the electron beam to the basin.

Further, in the case where the main lens is formed between the fifth electrode 95 and the sixth electrode 96 by supplying the anode voltage to the sixth electrode 96, the fifth electrode 95 and the sixth electrode forming the main lens. The shape of the electron beam passage port 96 has a great influence on the shape of the electron beam spot in the large current region, but the influence on the shape of the electron beam spot in the small current region is smaller than that in the large current region.

The length of the fourth electrode 94 of the electron gun in the tube axis direction affects the magnitude of the optimum focus voltage,
Moreover, the difference between the optimum focus voltages at the time of the small current and the large current is remarkably influenced, but the influence of the length change of the fifth voltage 95 in the tube axis direction is remarkably smaller than that of the fourth electrode 94.

Therefore, in order to optimize each characteristic value of the electron beam, it is necessary to optimize the structure of the electrode that most effectively acts on each characteristic.

However, the diameter of the bright spot drawn by the electron beam spot on the fluorescent screen depends on the spherical aberration of the main lens. This spherical aberration can be reduced by increasing the diameter of the main lens.

Further, when the hole pitch of the shadow mask in the direction perpendicular to the electron beam scanning direction of the cathode ray tube is made small or the density of the electron beam scanning lines is made large, the electron beam and the shadow are shadowed especially in the small current region of the electron beam. Since optical interference (moiré) occurs with the mask, it is necessary to optimize the so-called moire contrast for reducing this moire.

However, the above-mentioned conventional techniques cannot overcome the above-mentioned various problems.

The object of the present invention is to solve the above-mentioned problems of the prior art, improve the focus characteristics in the entire current region of the electron beam, and obtain a good resolution.
It is to provide a cathode ray tube equipped with an electron gun configured to reduce moire in a small current region.

[0031]

To achieve the above object, the present invention provides a panel portion having a fluorescent screen, a neck portion for accommodating an electron gun, and a funnel portion for connecting the panel portion and the neck portion. And a cathode, a control electrode, a focusing electrode, and an anode electrode that are housed in the neck portion and that have a plurality of electron beam passage openings facing the focusing electrode. A cathode ray that includes at least an electron gun using a plurality of electron beams in an in-line arrangement that forms a main lens with the anode electrode having an electrode, and a deflecting device that is externally mounted in a transition region of a funnel portion and a neck portion of the vacuum envelope. In the tube, a member that is coaxially connected to the electron gun and is connected to the anode electrode and installed between the fluorescent screen and the electron gun is provided to position the electron gun in the vacuum envelope. On the anode side bottom of the order of the tubular electrode component, characterized in that a phosphor screen side diameter and the opening of substantially the same diameter of the anode electrode.

Further, according to the present invention, there is provided a vacuum envelope comprising a panel portion having a phosphor screen, a neck portion for accommodating an electron gun, and a funnel portion connecting the panel portion and the neck portion, and the inside of the neck portion. Accommodated cathode, control electrode,
An electron gun including a focusing electrode and an anode electrode and using a plurality of electron beams in an in-line arrangement in which a main lens is constituted by the anode electrode facing the focusing electrode, and a transition region of a funnel portion and a neck portion of the vacuum envelope. In a cathode ray tube including at least a deflection device that is externally mounted on the cathode, the electron gun is coaxially connected to the anode electrode and is installed between the phosphor screen and the electron gun so as to position the electron gun in the vacuum envelope. It is characterized in that an opening having a diameter substantially the same as the diameter of the fluorescent surface side of the anode electrode is provided in the bottom portion on the anode side of the tubular electrode component for attaching a member for performing.

Further, according to the present invention, a vacuum envelope comprising a panel portion having a phosphor screen, a neck portion for accommodating an electron gun, and a funnel portion connecting the panel portion and the neck portion, and a vacuum envelope in the neck portion are provided. An electron gun which is housed and includes a cathode, a control electrode, a focusing electrode, and an anode electrode, and which uses a plurality of electron beams in an in-line arrangement in which a main lens is constituted by the focusing electrode and the anode electrode facing the focusing electrode, and the vacuum envelope In a cathode ray tube having at least a funnel portion and a deflection device provided in a transition region of a neck portion, the vacuum envelope is installed coaxially with the electron gun and connected to the anode electrode and between the phosphor screen. A plurality of electron beam passage openings for focusing control are formed in the bottom portion on the anode side of the cylindrical electrode component for mounting a member for positioning the electron gun in the inside. To.

Furthermore, the present invention is characterized in that the length of the anode electrode in the tube axis direction is substantially equal to or smaller than the opening diameter in the direction perpendicular to the in-line arrangement direction.

[0035]

In order to increase the diameter of the main lens, it is necessary at the same time that the anode electrode constituting the main lens has a proper length in the axial direction of the cathode ray tube. The reason for this is to weaken the electric field in the electrode and reduce spherical aberration.

Generally, in a cathode ray tube, the entire area from the anode to the phosphor screen is at the same potential as the anode, and therefore, among the electrodes constituting the main lens of the electron gun, the electrode portion between the anode and the tubular electrode part. That is, by providing the bottom of the tubular electrode component with an opening having substantially the same diameter as the opening on the phosphor screen side of the anode as in the configuration of the present invention, the direction of the phosphor screen from the main lens facing portion of the anode (focusing electrode side). It is possible to weaken the strength of the electric field distributed in.

This suppresses the divergence of the electron beam passing therethrough, substantially increasing the diameter of the main lens, and obtaining a focus characteristic with good resolution.

Even if the length of the anode electrode in the tube axis direction is shortened, it does not change, and a plurality of electron beam passage openings for focusing control to be installed inside the anode should be provided at the bottom of the cylindrical electrode part. Therefore, a focus characteristic with good resolution can be obtained.

Then, the length of the anode electrode in the tube axis direction is substantially equal to the opening diameter in the direction perpendicular to the in-line arrangement direction, or
By making it either small or small, the length of the anode electrode in the tube axis direction can be shortened without impairing the focus characteristics, the total length of the electron gun can be shortened, and the depth size of the cathode ray tube can be shortened. The effect that the press forming process of the anode electrode is facilitated and the amount of the electrode material used is reduced is obtained, which is effective in cost reduction.

[0040]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a side sectional view of a main part of a built-in electron gun for explaining a first embodiment of a cathode ray tube according to the present invention.
95 is a focusing electrode, 96 is an anode electrode, 96-1 is an internal electrode, 97 is a tubular electrode, 97-1 is the bottom of the tubular electrode, 97
-1 'is an aperture and E is an electric field distribution.

FIG. 2 is a plan view seen from the direction AA of FIG.

In FIGS. 1 and 2, an anode electrode 96 is connected to the cylindrical electrode 97, and a focusing control internal electrode 96 having a plurality of electron beam passage openings inside the anode electrode 96.
-1 is provided. In the internal electrode 96-1, the electron beam passage openings a, b and c are formed to be long (longitudinal) in the direction orthogonal to the in-line arrangement direction as shown in FIG. a and c are formed by the internal electrode 96-1 and the inner wall of the anode.

In such an electrode structure, the focusing electrode 9
5 and the main lens electric field E formed in the opposing portion of the anode electrode 96 are distributed gently inside the tubular electrode, beyond the opening 97-1 'provided in the bottom portion 97-1 on the tubular electrode 97 side. , Acts as a substantially large-diameter lens on the electron beam passing in the fluorescent screen direction.

Since the above effect does not change even if the length of the anode electrode 96 in the tube axis direction is shortened, the length L of the anode electrode 96 in the tube axis direction is defined by the opening diameter D in the direction perpendicular to the in-line arrangement direction. The length of the electron gun in the tube axis direction can be reduced by setting the value to be substantially equal to or smaller than.

FIG. 3 is a side sectional view of the main part of the built-in electron gun for explaining the second embodiment of the cathode ray tube according to the present invention.
95 is a focusing electrode, 96 is an anode electrode, 97 is a cylindrical electrode, 9
7-1 is the bottom of the cylindrical electrode, and E is the electric field distribution.

FIG. 4 is a plan view seen from the direction AA of FIG.

3 and 4, the point different from the above embodiment is that an inner electrode for focusing control, which is to be provided inside the anode 96, is provided in the shape of the bottom portion 97-1 of the cylindrical electrode 97.

That is, instead of the internal electrode 96-1 for controlling the focusing of the electron beam installed inside the anode electrode 96 in the first embodiment, the bottom portion 97- of the cylindrical electrode 97 is used.
1 has an opening having the same shape as the internal electrode 96-1.

Also in this embodiment, similarly to the above, the electric field E of the main lens can be gently distributed inside the cylindrical electrode 97, and the electron beam passing in the fluorescent screen direction can be used as a substantially large-diameter lens. Can be operated.

The above effect does not change even if the length of the anode electrode 96 in the tube axis direction is shortened. Therefore, the length L of the anode electrode 96 in the tube axis direction is defined by the opening diameter D in the direction perpendicular to the in-line arrangement direction. It is similar to the above-described embodiment that the length of the electron gun in the tube axis direction can be reduced by setting it to be substantially equal to or smaller than.

The present invention is not limited to the above-mentioned embodiment, but a member and a getter for positioning the electron gun in the vacuum envelope are provided on the phosphor screen side of the electrode constituting the main lens. An electron gun having an electrode part for attachment, or a cathode ray tube and a color cathode ray tube having various electron guns having a structure for attaching a member for positioning the electron gun as a part of the anode and a getter, etc. Needless to say, it can be applied to the cathode ray tube.

[0053]

As described above, according to the present invention,
It is possible to improve the focus characteristics in the entire current range of the electron beam, obtain good resolution, and provide a cathode ray tube equipped with an electron gun configured to reduce moire in a small current range. The length of the anode electrode in the tube axis direction can be shortened, the effect that the total length of the electron gun can be shortened and the depth size of the cathode ray tube can be shortened, and the press molding process of the anode electrode can be facilitated. , And the advantage that the amount of electrode material used is reduced, which is effective in cost reduction.

[Brief description of drawings]

FIG. 1 is a side sectional view of a main part of a built-in electron gun for explaining a first embodiment of a cathode ray tube according to the present invention.

FIG. 2 is a plan view of the built-in electron gun for explaining the first embodiment of the cathode ray tube according to the present invention as seen from the direction AA of FIG.

FIG. 3 is a side sectional view of a main part of a built-in electron gun for explaining a second embodiment of the cathode ray tube according to the present invention.

FIG. 4 is a plan view of the built-in electron gun for explaining the second embodiment of the cathode ray tube according to the present invention as seen from the direction AA of FIG.

FIG. 5 is a cross-sectional view illustrating the structure of a shadow mask type color cathode ray tube as an example of the color cathode ray tube.

FIG. 6 is a side view illustrating an example of an electron gun housed in a neck portion of a color cathode ray tube.

FIG. 7 is a side sectional view of an essential part for explaining an electrode configuration around a main lens in a conventional electron gun.

8 is a plan view illustrating an electrode configuration around a main lens in a conventional electron gun viewed from the AA direction in FIG.

[Explanation of symbols]

 95 Focusing electrode 96 Anode electrode 96-1 Internal electrode 97 Cylindrical electrode 97-1 Bottom part of cylindrical electrode 97-1 'Opening E Electric field distribution.

Claims (4)

[Claims] 1. A vacuum envelope comprising a panel section having a phosphor screen, a neck section for accommodating an electron gun, and a funnel section connecting the panel section and the neck section, and a cathode housed in the neck section. , A control lens, a focusing electrode, and an anode electrode, and the main lens is constituted by the anode electrode having the focusing control internal electrode facing the focusing electrode and having a plurality of electron beam passage openings. In a cathode ray tube including at least an electron gun using a plurality of electron beams and a deflection device externally mounted in a transition region of a funnel portion and a neck portion of the vacuum envelope, the cathode electrode is connected to the anode electrode coaxially with the electron gun. The anode electrode is provided on the anode-side bottom of a tubular electrode component that is installed between the fluorescent screen and a member for positioning the electron gun in the vacuum envelope. A cathode ray tube, which is provided with an opening having a diameter substantially the same as the diameter of the phosphor screen side. 2. A vacuum envelope comprising a panel section having a phosphor screen, a neck section for accommodating an electron gun, and a funnel section connecting the panel section and the neck section, and a cathode housed in the neck section. An electron gun including a control electrode, a focusing electrode, and an anode electrode and using a plurality of electron beams in an in-line arrangement in which a main lens is constituted by the anode electrode facing the focusing electrode, and a funnel portion and a neck of the vacuum envelope. A cathode ray tube provided with at least a deflection device provided in a transition region of the electron gun, the electron gun being coaxially connected to the electron gun, being installed between the anode electrode and the fluorescent screen, and being provided in the vacuum envelope. A cathode ray tube characterized in that an opening having a diameter substantially the same as the diameter of the fluorescent surface of the anode electrode is provided in the bottom portion of the cylindrical electrode component for mounting the member for positioning the anode side. 3. A vacuum envelope comprising a panel portion having a phosphor screen, a neck portion for accommodating an electron gun, and a funnel portion for connecting the panel portion and the neck portion, and a cathode housed in the neck portion. An electron gun including a control electrode, a focusing electrode, and an anode electrode and using a plurality of electron beams in an in-line arrangement in which a main lens is constituted by the anode electrode facing the focusing electrode, and a funnel portion and a neck of the vacuum envelope. A cathode ray tube provided with at least a deflection device provided in a transition region of the electron gun, the electron gun being coaxially connected to the electron gun, being installed between the anode electrode and the fluorescent screen, and being provided in the vacuum envelope. 2. A cathode ray tube, wherein a plurality of electron beam passage openings for focusing control are formed in the bottom portion on the anode side of a tubular electrode component for attaching a member for positioning. 4. The tube length in the tube axis direction of the anode electrode according to claim 1, 2 or 3, which is substantially equal to or smaller than an opening diameter in a direction perpendicular to the in-line arrangement direction. And a cathode ray tube.