JPH0143422B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun electrode assembly for a color cathode ray tube that generates a plurality of electron beams. The present invention relates to an electron gun electrode assembly with an integrated electrode forming an electron lens.

The electron guns commonly used in color cathode ray tubes are bi-potential electron guns, which have excellent focusing characteristics for electron beams and have the simplest structure.
This is a focus type electron gun, and the volume occupied by the electron gun electrode structure has been improved by simplifying the assembly of the electron gun electrode structure, improving assembly accuracy, or reducing the diameter of the neck of the glass envelope in which the electron gun is sealed. As a means of reducing the size of the electron beam, an electrode structure is provided which is electrically common and has integrated electrodes in each electron beam path forming substantially individual or common electron lenses.

In this case, a large potential difference occurs between the G3 electrode, which is the focusing electrode, and the G4 electrode, which is the anode electrode, forming the main electron lens, so the electrode support structure greatly affects the withstand voltage characteristics.

Figures 1 and 2 show a conventional in-line bipotential focus type electron gun electrode structure 1 in which cathodes are arranged in the same plane, electrically insulated from each other and kept at equal distances. 3 is a front view and a side view of B- shown in FIG. 1, respectively.
B′ section is shown.

That is, the electron gun electrode assembly 1 includes three cathode assemblies 10 that are insulated from each other and arranged in a line at equal distances in the same plane, and an electric cathode assembly 10 that is arranged in sequence in the electron beam traveling direction in opposition to these cathode assemblies 10. The G1 electrode 11 is a common control electrode, and the G2 electrode 12 is an acceleration electrode for the thermionic beam emitted from the cathode. A G3 electrode 13, which is a focusing electrode made of an integrated electrode forming a lens, and a G4 electrode 14, which is an anode electrode to which a high voltage is applied, are arranged on the same axis in the electron beam traveling direction. Each electrode has a supporter 15, and by embedding each supporter 15 in two rectangular columnar insulator support rods 16 and fusing them, the electrode spacing is maintained and fixed at a predetermined dimension.

Taking the G3 electrode 13 that constitutes the main electron lens as an example, and looking at its electrode support structure, as shown in the cross section perpendicular to the electron beam traveling direction shown in FIG.
Three openings 13R, 13 aligned on a straight line and bored as the center and both outer electron beam transmission holes
G, 13B is a closed cylindrical body having a closed end face and a cylindrical side portion in a substantially rectangular or elliptical shape that is long in the arrangement direction and short in the direction perpendicular to the arrangement direction,
The open end is integrally formed with a flanged edge 13A extending at right angles to the cylinder side, and the flanged edge 13A on the long side
An electrode supporter 15 is provided at the tip with a plurality of notches 15A in order to increase the strength of the fusion bond with the insulator support rod 16. Conventionally, the G3 electrode 13 was constructed by overlapping two closed cylindrical electrodes 13 _-1 and 13 _-2 with a flange-like edge, each having a cylindrical side section that bisects the axial length necessary for the G3 electrode 13. Was.

On the other hand, G3 electrode 13 and G4 electrode 1, where a high potential difference occurs
The withstand voltage characteristics between the two electrode supports are largely dependent on the distance between the two electrodes, the surface condition of the opposing electrode surfaces, and the mutual distance _A1 between the two electrode supports along the surface of the insulator support rod 16. Normally, the above-mentioned electrode spacing is selected to be about 0.8 to 1.5 mm, and considering that cathode ray tubes operate in high vacuum, they have a withstand voltage characteristic of about 50 to 80 kV, so there is no problem in practical use. The surface condition can also be made clean without any problems in terms of withstand voltage by treatment in the manufacturing process of electron gun electrode structures and cathode ray tubes. Therefore, it can be said that the main factor that determines the withstand voltage characteristics between the electrodes is the distance between the two electrode supports along the surface of the insulator support rod 16. However, conventionally, as mentioned above, two closed cylindrical electrodes 13 _-1 and 13 _-2 , each having a cylindrical side section that bisects the axial length necessary for the G3 electrode 13, are overlapped at the brim-like edge. Since the G3 electrode 13 was configured, the distance A ₁ between the opposing electrode supports 15 of the G3 electrode 13 and the G4 electrode 14 is determined by the design of the electron gun electrode structure 1.
It was limited to the cylindrical side portion of the electrode 14, and could not be large enough in terms of withstand voltage. In particular, when the electron gun electrode structure 1 is downsized, the relative dimensions of the electrodes are reduced and the distance between the electrode supports is also reduced, but the operating conditions are often almost the same, that is, the G3 electrode 1
Since the potential difference between G3 and G4 electrodes 14 is almost the same and the mutual distance between the electrode supports becomes small, the withstand voltage characteristics deteriorate. Alternatively, in order to strengthen the support strength of the G3 electrode 13, which is a closed cylindrical electrode, a pair of U-shaped auxiliary supports 17 having an end fused to an insulator support rod 16 at the tip as shown in FIG. Electrode 13 _-2 is sometimes used fixed approximately in the middle of the long side of the tube, and in this case, G3 electrode 13 and G4 electrode 1
The distance along the surface of the insulator support 16 between the opposing electrode supports of No. 4 becomes even smaller, degrading the withstand voltage characteristics between the electrodes.

The object of the present invention is to provide an electron gun electrode structure which eliminates the above-mentioned drawbacks. According to the invention,
a closed end face having a plurality of electron beam transmission holes that are electrically and structurally common and that form substantially individual or common electron lenses in each electron beam path;
A closed cylindrical shape that has a cylindrical side section that is approximately perpendicular to this, and a flange-shaped edge that extends at right angles to the open end side of this cylindrical side section, and a part of the flange-shaped edge is used as an electrode supporter. An integrated focusing electrode formed by overlapping two body electrodes with their brim-shaped edges and an anode electrode having the same shape as the closed cylindrical body electrode are made to face each other to form a bipotential focus type main electron lens. In the electron gun electrode structure forming the integrated focusing electrode,
By forming two closed cylindrical body electrodes with different axial lengths overlapping each other so that the distance between the electrode supports of the integrated focusing electrode and the anode electrode becomes large, the focusing electrode and the anode electrode with a high potential difference are formed. An electron gun electrode structure with good withstanding voltage characteristics between the anode electrodes can be obtained.

An embodiment of the present invention will be described in detail below with reference to the drawings. 5 and 6 are respectively front views of an in-line electron gun electrode structure 2 showing an embodiment of the present invention;
It is a side view, and for the sake of simplification of explanation, the same parts as the conventional one are given the same reference numerals.

That is, the electron gun electrode assembly 2 includes a cathode assembly 10 consisting of three cathodes arranged in a row on the same plane, insulated from each other and spaced apart from each other, and facing the cathode assembly 10, in which the electron beam advances. A G1 electrode 11 which is an electrically and structurally common control electrode, a G2 electrode 12 which is an acceleration electrode, a G3 electrode 23 which is a focusing electrode, and a G4 electrode 14 which is an anode electrode are arranged sequentially in the direction.
are arranged on the same axis, which is the electron beam traveling direction, and each electrode has a support element 15 formed integrally with the electrode, which is embedded in two rectangular column-shaped insulator support rods 16 and fused together, so that the distance between each electrode can be adjusted. It is held and fixed at a predetermined size. The G3 electrode 23, which is constructed by overlapping two closed cylindrical electrodes 23 _-1 and 23 _-2 at their flanged edges, has the same overall length in the axial direction, which is the electron beam traveling direction, as the conventional G4 electrode. The cylindrical portion of the G3 electrode 23 _-2 facing the G2 electrode 14 is set to be longer than the cylindrical portion of the G3 electrode 23 _-1 facing the G2 electrode 12 as much as possible in terms of electrode molding. For this reason, the distance A ₂ between the opposing electrode supports 15 of the G3 electrode 23 and the G4 electrode 14 is set larger than the distance A ₁ between the supports when the G3 electrode 13 is conventionally divided into equal parts.

As described above, according to the embodiment of the present invention, the distance A ₂ between the opposing electrode supports of the G3 electrode 23 and the G4 electrode 14, where a high potential difference occurs, is set larger than in the past, so that a high potential difference occurs between the two electrodes. The shortest leakage current path formed between the opposing electrode supports along the surface of the insulator support rod 16 through which a leakage current leading to dielectric breakdown flows becomes larger, and the withstand voltage against the high voltage applied between the electrodes increases. It can be made long enough. Alternatively, in order to improve the withstand voltage characteristics between the electrodes where the above-mentioned high potential difference occurs during the cathode ray tube manufacturing process, a high voltage several times higher than the rated voltage of the anode that is actually used is applied to remove minute protrusions on the surface of the opposing electrode. There is a high-voltage treatment process to remove dirt, etc., but since the shortest leakage current path between the G3 electrode 23 and the G4 electrode 14 is set larger than before, it is possible to increase the high-voltage treatment voltage to a higher level than before. , the surface state of the counter electrode can be kept clean against higher voltages, and the withstand voltage characteristics can be further improved.

Furthermore, even if an auxiliary support for reinforcing the supporting strength of the conventionally used closed cylindrical electrode is attached to the tube side on the longer side of the electrode, the G3 electrode 23 and the G4 electrode 1
The shortest leakage current path along the insulator support rod 16 between the opposing electrode supports of No. 4 is increased, and the withstand voltage characteristics between the electrodes are dramatically improved. Alternatively, in the case of an electron gun electrode structure used in a cathode ray tube in which the neck of the cathode ray tube glass envelope in which the electron gun electrode structure is sealed is thinner, the relative dimensions of the electrodes are reduced, but if the embodiments of the present invention are applied, the height can be increased. Since the mutual distance between the opposing electrode supports at which a potential difference occurs can be set large, the withstand voltage characteristics are not deteriorated. Furthermore, the three aperture diameters formed on the opposing closed surfaces of the G3 and G4 electrodes, which normally form the main electron lens, are as large as possible in order to eliminate aberrations and improve focus characteristics as a long focus lens. It is desirable that the long diameter of the three apertures in the closed end face in which the apertures are formed in the direction in which they are lined up is set as large as possible within the range that fits within the inner diameter of the glass neck where the electron gun electrode assembly is sealed. The flanged edge on the short side is very close to the inner wall of the glass neck, and faces the inner wall of the glass neck perpendicularly and with a sharp cut surface, and the focused voltage supplied to the G3 electrode is concentrated on this part. On the other hand, the area near the inner glass wall facing the side of the G4 electrode tube is at a high voltage anode potential supplied from the conductive coating applied to the inner wall of the glass neck, and the inner wall of the glass neck facing the G3 and G4 electrodes has a large potential. A slope is created, and during this time a leakage current path is formed depending on the surface condition of the tube wall, which causes deterioration of the withstand voltage characteristics between the two electrodes. In this case, according to the embodiment of the present application, the short-side flanged edge of the G3 electrode 23 having a sharp cut surface, which is close to and opposite to the inner wall of the glass neck of the cathode ray tube envelope, is moved away from the G4 electrode 14 so as to be aligned along the inner wall of the glass neck. The leakage current path can also be set large, and the withstand voltage characteristics of the electron gun electrode structure can be further improved.

FIG. 7 is a side view of an in-line electron gun electrode assembly 3 showing another embodiment of the present invention. G4 electrode 3
As is clear from the figure, 4 is composed of two closed cylindrical body electrodes 34 _-1 and 34 _-2 stacked at their brim-shaped edges, and the closed cylindrical body electrode 34 _- on the side opposite to the G3 electrode 33 The axial length of the cylinder side part along the electron beam traveling direction of _{No. 1} is set to be larger than that of the other electrode _34-2 , and this is synergistic with the uneven division of the G3 electrode 33.
The shortest leakage current path along the surface of the insulator support rod 16 between the opposing electrode supports of the G3 electrode 33 and the G4 electrode 34 is set to be large. Therefore, according to this embodiment, the withstand voltage characteristics between the electrodes where a high potential difference occurs can be dramatically improved.

[Brief explanation of drawings]

Both figures 1 and 2 show in-line bi-potential tubes used in conventional color cathode ray tubes.
A front view and a side view of the focus type electron gun electrode structure, FIG. 3 shows the BB' cross section shown in FIG. 1, and FIG. 4 shows a perspective view of the closed cylindrical electrode provided with an auxiliary support. 5 and 6 are a front view and a side view, respectively, of an in-line type bi-potential focus type electron gun electrode structure showing one embodiment of the present invention, and FIG. 1 is a side view of an in-line bi-potential focus type electron gun electrode assembly showing an example. 10... Cathode structure, 11... G1 electrode, 12... G2 electrode, 1
3, 23, 33...Occluded cylindrical body G3 electrode, 14,
24, 34... Closed cylindrical body G4 electrode, 15... Electrode supporter, 16... Insulator support rod, 17... U-shaped auxiliary support.

Claims (1)

[Claims] 1 It has a closed end face with a plurality of electron beam transmission holes, a cylinder side part that is approximately perpendicular to the closed end face, and a flange-shaped edge that extends at right angles to the open end side of this cylinder side part. an integrated focusing electrode formed by overlapping two closed cylindrical electrodes, each of which has a part of the rim serving as an electrode supporter, and an anode having the same shape as the closed cylindrical electrode; Place the electrodes facing each other and
In the electron gun electrode structure forming a potential focus type main electron lens, the integrated focusing electrode integrates two closed cylindrical body electrodes having different axial lengths, and is an electrode supporter for the focusing electrode and the anode electrode. 1. A cathode ray tube electron gun electrode structure, characterized in that the electrode structures are stacked one on top of the other so that the distance between them is large.