JPH03210737A - Electron gun structural body for cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain an electrode structural body having a good withstand voltage by making the axial lengths of two closed cylindrical electrodes, which form a united pair of first and second electrodes near a cathode, longer on the side near the cathode than on the other side. CONSTITUTION:The distance B1 between electrode supports 18 for a G4 electrode 24, which is nearest a cathode 10 and to which a high anode voltage is applied, and for a G3 electrode 23, which is set on the opposite to the electrode 24 in the cathode 10 side, is so determined as to become larger than the distance between supports 18 in the case of dividing the closed cylindrical electrodes equally. Consequently, the shortest leakage current route which is formed between the electrode supports along an insulator supporting rod 19 becomes large as well and become enough length for withstand voltage between the electrodes 23 and 24. During the withstand voltage treatment in manufacturing process, danger of excess leakage current owing to dielectric breakdown between electrodes running into a cathode becomes low and thus the treatment voltage can be set high and withstand voltage property between electrodes where high potential difference is caused becomes good. Mutual distance B2, B3 between supports for G4 electrode 24 and G5 electrode 25, and the electrode 25 and G6 electrode is also made large.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-electron gun electrode structure for a color cathode ray tube that generates a plurality of electron beams, and in particular, to a multi-electron gun electrode structure for a color cathode ray tube that is electrically and structurally common and has a substantially individual electron lens in each electron beam path. The present invention relates to an electron gun electrode structure having an integrated electrode formed therein.

Simplify assembly work of electron gun electrode structure, improve assembly accuracy,
Alternatively, as a means of reducing the volume occupied by the electron gun electrode structure due to the reduction in diameter of the neck of the glass envelope in which the electron gun of a color cathode ray tube is sealed, each electron beam passage is electrically and structurally common. Electron gun electrode assemblies with integral electrodes that form essentially separate electron lenses are commonly used. Furthermore, as a means to significantly improve the focusing characteristics of the main electron lens of the electron gun for the electron beam, an electron gun equipped with a multistage focusing electron lens that combines multiple electron lenses instead of using a single main electron lens has been used. However, depending on the electrode configuration, the axial length of the electrode may be the same as or less than the gap between the opposing electrodes, and the mutual distance between the electrode supports may also be about the same as the gap between the opposing electrodes. . Therefore, when different high voltages are applied between the electrodes during operation of the electron gun, and a large potential difference occurs between the opposing electrodes, the withstand voltage characteristics between the electrodes are significantly deteriorated.

In particular, the withstand voltage characteristics between the electrodes closest to the cathode, where a high voltage difference occurs, are important, and if dielectric breakdown occurs due to poor withstand voltage characteristics, a leakage current with a large capacity will instantly flow, and this will flow to the cathode. may also flow in and damage the cathode, destroying its thermionic emission properties and preventing the required current from being extracted from the cathode.

These problems will be explained using one of the conventionally used electron gun electrode structures equipped with a multi-stage focusing electron lens.

Figures 1 and 2 show a conventional in-line type in which cathodes are arranged in the same plane, electrically insulated from each other and equally spaced apart, and the main electron lens has three pi potentials.・A front view and a side view of an electron gun electrode assembly l employing a multi-stage focusing electron lens system in which focusing electron lenses are stacked, and FIG. 3 shows a cross section taken along the line AA shown in FIG. 1.

The electron gun electrode assembly 1 includes cathode assemblies 10 which are insulated from each other and arranged in a line at equal distances in the same plane, and electrically common cathode assemblies 10 which are arranged in sequence in the electron beam traveling direction in opposition to these cathode assemblies 10. The G1 electrode 11, which is a control electrode, and the G2 electrode 12, which is an acceleration electrode for the thermionic beam emitted from the cathode, are electrically and structurally common and form substantially independent electron lenses in each electron beam path. It is composed of a G3 electrode 13 which is a first focusing electrode, a G4 electrode 14 which is a first anode electrode, a G5 electrode 15 which is a second focusing electrode, and a G6 electrode 16 which is a second anode electrode.

Each electrode has a support element 18 having a plurality of notches 18A at its tip to increase the strength of the fusion bond with the insulator support rod 19,
By embedding the notch 18A of the supporter 18 into the two rectangular columnar insulator support rods 19 and fusing them, the distance between each electrode is maintained and fixed at a predetermined dimension. G4 electrode 14 and G6 electrode 1
6 are connected to the same potential by the power supply line 17A,
Although not shown, a high anode voltage of about 20 to 30 kV is supplied from an internal conductive coating connected to an anode terminal provided in the funnel-shaped part of the cathode ray tube glass envelope in which the electron gun electrode structure 1 is sealed. be done. The G3 electrode 13 and the G5 electrode 15 are brought to the same potential by a power supply line 17B, and although not shown, a focused voltage of about 20 to 40% of the anode voltage is supplied from a power supply pin of the stem on which the electron gun electrode structure 1 is supported and fixed. The other electrodes are also connected to the power supply pin of the stem so that a predetermined voltage is supplied from the power supply pin of the stem. The electron beam emitted from the cathode lO is diverged from a crossover point formed near the Gl electrode 11 and the G2 electrode 12, and the electron beam is emitted from the G2 electrode 12.
After being pre-focused by a pre-focus lens formed between the G3 electrode 13 and the G3 electrode 13, the G3 electrode 13 and the G4 electrode 14,
G4'[i14 and the G5 electrode 15, the G5 electrode 15 and the G6 electrode 16 are formed in the gap between the electrodes, and three independent pi-potential type lenses, which are the main focus lenses, are used to sequentially focus the light in three stages. The focusing voltage is adjusted to have a minimum beam spot cross section at the top.

The electron beam pre-focused by the pre-focus lens is focused in three stages by three main focus lenses, so the main focus lens is different from the one main focus lens in the conventional electron gun.・The strength of each lens can be made weaker than that of the lens, and the three main lenses can gradually focus the electron beam, so the spherical aberration of the main lens system is extremely small, and even when the electron gun has a large beam current, the electron beam The beam passes through the center of each main electron lens where the aberration is small, resulting in a sharp beam beam, and a high-resolution received image can be obtained on the phosphor screen even on a high-brightness screen.

Taking the G5 electrode 15, which constitutes one of the main electron lenses, as an example, and looking at its electrode support structure in detail, we can see that the electrodes are aligned in a straight line as shown in the cross section perpendicular to the electron beam traveling direction shown in FIG. Three openings 15R are drilled as central and both outer electron beam transmission holes.

It is a closed cylindrical body having a closed end face and a cylindrical side portion, which are long in the arrangement direction of 15G and 15B and have a substantially rectangular or elliptical shape and short in the direction perpendicular to the arrangement direction, and the open end has a cylindrical side portion. A flange-shaped edge 15A extending at right angles is integrally formed with the flange-shaped edge 15A, and a plurality of notches 18A are provided on the longer side of the flange-shaped edge 15A to increase the strength of the fusion bond with the insulator support rod 19. It is provided at the tip to constitute an electrode supporter 18, and the two closed cylindrical bodies are overlapped with each other at the brim-shaped edge 15A.

As mentioned above, a high anode voltage is applied to the G4 electrode 14 and the G6 electrode 16, a high voltage of about 20 to 40% of the anode voltage is applied to the G3 electrode 13 and the G5 electrode 15, and the G3 electrode 13 and the G4 electrode 14. Since a large potential difference occurs between the G4 electrode 14 and the G5 electrode 15, and between the G5 electrode 15 and the G6 electrode 16, the distance between the opposing electrodes and the distance between the supports embedded in the insulator support rods must be adjusted to withstand Significantly affects voltage characteristics. The larger the distance between the electrodes, the better in terms of withstand voltage characteristics, but if it is too large, the electron beam path in the electron beam passage hole will be undesirably bent due to the influence of external electric field penetration, so the electrode should be large enough to avoid this influence. has been selected. Also, the withstand voltage characteristics between the electrode supports 18 of the G3 electrode 13, G4 electrode 14, G5 electrode 15, and G6 electrode 16 are determined by the insulator support rod 19.
It is determined by the minute leakage current that flows depending on the specific resistance value due to the composition and the surface resistance value due to the surface condition, etc. In the vacuum atmosphere inside the tube during operation of the cathode ray tube, the voltage resistance between the electrode supports is determined by the withstand voltage characteristics of the spacing between the electrodes. Since the withstand voltage characteristics are more dominant, G3 electrode 13 and G4 electrode 14, G4 electrode 14
The distance A1°At, As between the electrode supports 18 of the G5 electrode 15 and the G6 electrode 16 is as large as possible based on the design of the electron gun electrode structure, and the shortest leakage current path along the insulator support rod 19 is Larger is desirable.

However, the distance between the electrode supports 18 is determined by the axial length of each electrode determined from the focus characteristics and the mutual spacing between the electrodes.
Conventionally, the G3 electrode 13, the G4 electrode 14, and the G5 electrode 15 are two closed cylindrical body electrodes 13-+ whose length is obtained by dividing the required axial length into thirds.

13-z, 14-1.14-! , 15-+, 1
5-z were formed by overlapping their brim-like edges.

Therefore, as shown in FIG. 2, the G3 electrode 13 and the G4 electrode 14
, each supporter 18 spacing A+ of G5 electrode 15 and G6 electrode 16
, At, and A'l are irregularly spaced, and especially include electrodes whose length in the axial direction is shorter than that of other electrodes (corresponding to the G4 electrode 14 in the electrode configurations shown in FIGS. 1 and 2). In this case, the spacing between the supports of each electrode adjacent to this electrode is A, ,
A! is another interval A.

, and the shortest leakage current path formed between the electrode supports 18 along the insulator support rods 19 is longer or shorter.
The length of the shortest path is insufficient to withstand the high voltage applied between the electrodes, or to improve the withstand voltage characteristics between the electrodes where the above-mentioned high potential difference occurs during the cathode ray tube manufacturing process. There is a high-voltage treatment process in which a high voltage several times the rated voltage of the anode actually used is applied to remove minute protrusions and dirt on the electrode surface. A high load is applied to the smallest path in the current path, and since leakage current is concentrated during this period, it is not possible to apply too much high voltage to perform high voltage processing, and the quality of withstand voltage characteristics does not improve much. In particular, the withstand voltage characteristics between the G3 electrode 13 and the G4 electrode 14, which are closest to the cathode 10 and have a high potential difference, are important. If the withstand voltage characteristics are poor and dielectric breakdown occurs, a large capacitance will instantly occur between the electrode supports. A leakage current flows, which also flows into the cathode 10, damaging the thermionic emission surface of the cathode 10, deteriorating or destroying the thermionic emission characteristics of the cathode 10, and making it impossible to extract the necessary current from the cathode. In addition, due to this cathodic protection, the high voltage processing voltage mentioned above is also limited, making it impossible to perform sufficient withstand voltage processing.
The withstand voltage characteristics are not of sufficiently satisfactory quality.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide an electron gun electrode assembly for a cathode ray tube that has excellent withstand voltage characteristics.

In the present invention, a main electron lens is constructed by arranging a plurality of closed cylindrical electrodes facing each other, and in an electron gun electrode structure that generates a large potential difference between the electrodes arranged opposite to each other, a high potential difference closest to the cathode occurs. This is an electrode structure with improved voltage resistance characteristics between the electrodes.

More specifically, it is electrically and structurally common, and has a closed end face in which multiple electron beam transmission holes are drilled, and a cylinder side part that is approximately perpendicular to this, and a cylinder side part of the open end example has a support member. An electron gun electrode in which an electron lens is formed by forming a plurality of integral electrodes made by stacking two closed cylindrical electrodes each having a flange-like edge and facing each other.In the structure, the high potential difference closest to the cathode is By unequally dividing the axial length of at least two sets of integrated electrodes, the spacing between the opposing electrode supports, where the high potential difference occurs, is set larger than when the electrodes are equally divided. shall be.

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 4 is a side view of an electron gun electrode assembly showing a reference example of the present invention, and the same parts as in the conventional one are given the same reference numerals.

The electron gun electrode assembly 20 includes cathode assemblies lO which are insulated from each other in the same plane and are insulated and arranged in a line with equal distances between each other.
Opposed to this is a Gl electrode 11, which is an electrically common control electrode, and a cathode 1, which are arranged in sequence in the electron beam traveling direction.
G2 electrode 12 is an accelerating electrode for the thermionic beam emitted from zero, and a first focusing electrode consisting of an integrated electrode that has a common electrical structure and forms a substantially independent electron lens in each electron beam path. It is configured in the same way as in the conventional case, including a G3 electrode 23, a G4 electrode 24 which is a first anode electrode, a G5 electrode 25 which is a second focusing electrode, and a G6 electrode 26 which is a second anode electrode. Each electrode has a supporter 18 in which a part embedded in the insulator support rod 19 is formed, and the buried part of each supporter 18 is embedded in two insulator support rods 19 and fused, so that each electrode is spaced apart. is held and fixed at a predetermined size. G as before
Although not shown, the 4th electrode 24 and the G6 electrode 26 are made to have the same potential through a power supply line, and are supplied with a high anode voltage of about 20 to 30 kV, and the G3 electrode 23 and the G-5 electrode 25 are at the same potential through a power supply line 17B. A focused voltage of about 20 to 40% of the anode voltage is supplied.

However, G3 electrode 23, G4 electrode 24, G5 electrode 25, G
The total length in the axial direction of the six electrodes 26 and the distance between the electrodes are exactly the same as in the past, but the length is the length obtained by dividing the axial length of each set of closed cylindrical body electrodes into three equal parts. Instead, two closed cylindrical body electrodes 23-, . 2
1! , 21. .

2L, 25-, . 25-1 are formed by overlapping their brim-shaped edges, and a part of it is formed into a support member 18 to an insulator support rod 19.
It becomes. The axial length of each electrode is divided, as shown in FIG.
A when the distance B+ between the electrodes 23 and the electrode supports 18 is equally divided, the G3 electrode 23- facing the 04 electrode 24-1 is made as large as possible from (Fig. 2)! The axial length of the G3 electrode 23-1 on the cathode 10 side is larger than that of the G3 electrode 23-1, and the axial length of the G4 electrode 24-6 facing the G3 electrode 23-2 is set to 0.
Closed cylindrical body electrodes are formed so as to be larger than the G4 electrode 24-3 facing the G5 electrode 25 and combined. The G5 electrode 25 has a similar structure in order to compensate for the reduction in the spacing between the supports of the G4 electrode 24, to which a high potential anode voltage is applied, which is reduced due to the effects of the G3 electrode 23 and the G4 electrode 24, and the 65 electrode 25, which has a lower potential. The axial length of the G5 electrode 25-1, which faces the G4 electrode 24-t, is adjusted so that the axial length of the G5 electrode 25-1, which faces the G4 electrode 24-t, faces the 06 electrode 26 to the extent that the distance between the electrode supports with the G6 electrode 26, to which a high potential anode voltage is applied, is not significantly reduced. The closed cylindrical body electrodes are formed so as to be larger than the G5 electrode 25-z, and are combined, thereby determining the mutual spacings Bt and Bs of the G4 electrode 24 and the G5 electrode 25, and between the G5 electrode 25 and the G5 electrode 26.

As described above, according to the embodiment of the present invention, the G4 electrode 24 closest to the cathode IO and to which a high anode voltage is applied, and the G3 electrode 23 electrode supporter disposed on the cathode 10 side opposite thereto. The distance B1 between the electrode supports 18 is selected to be as large as possible than the distance AI between the electrode supports 18 when the respective closed cylindrical electrodes are divided into equal parts. Similarly, the shortest leakage current path is made as large as possible, and the length is sufficiently large for the withstand voltage between the G3 electrode 23 and the G4 electrode 24, or the insulation between the electrodes is Since the risk of excessive leakage current flowing into the cathode due to breakdown has become extremely small, the processing voltage can be increased, and the withstand voltage characteristics between the electrodes, where a high potential difference occurs, are extremely good. Furthermore, the G4 electrode 24 and the G5 electrode 25°, the G5 electrode 25 and the G6 electrode 26, and the mutual spacing B2 and B3 of the supports are selected to be equal to or greater than the conventional mutual spacing At and Ax in the case of equal division, so that the G4 electrode 24 and G5 electrode 25. The withstand voltage characteristics between the G5 electrode 25 and the G6 electrode 26 are of higher quality than before.

In the above description, a multi-stage focusing electron gun having four main electron lens electrodes has been described, but a main electron lens having three main electron lens electrodes based on the embodiment of the present invention shown in FIG. It is also applicable to a potential focus type electron gun electrode structure. That is, the uni-potential focus electron is composed of the G3 electrode 33 and the 65 electrode, which are closed cylindrical body electrodes to which a high-potential anode voltage is applied, and the G4 electrode 34 to which a lower-potential focusing voltage is applied. In the lens, G2 electrode 12 and G3 electrode 33,
A very large potential difference is generated between the G3 electrode 33 and the G4 electrode 34, and between the G4 electrode 34 and the G5 electrode 35, and in particular between the G3 electrode 33 and the G2 electrode 12 closest to the cathode 10, the G2 voltage is usually used at about 1 kV or less. Therefore, a potential difference corresponding to the anode voltage applied to the G3 electrode 33 is generated, and the withstand voltage characteristics during this period are particularly important from the viewpoint of cathode protection. The overall length along the G3 electrode 33-1 and the spacing between all the electrodes are exactly the same as before, but the axial length of the closed cylindrical body electrode G3 electrode 33-1 facing the G2 electrode 12 is the same as that of the G3 electrode facing the G4 electrode 34. 334, and combine them to determine the support spacing C1. The G4 electrode 34 compensates for the reduction in the spacing between supports with the G3 electrode 33 to which a high voltage anode voltage is applied, which is reduced due to the influence of the G3 electrode 33, and the G5 electrode to which a high potential anode voltage is applied as well. The G4 electrode 3 faces the G3 electrode 23 to the extent that the distance between the electrode supports and the G3 electrode 23 is not significantly reduced.
4-1 is the G4 electrode 34- which faces the G5 electrode 35! G3 electrode 3 is formed and combined so that it becomes larger.
The mutual spacing C2°C1 between the supports of the G4 electrode 34 and the G4 electrode 34 and the G5 electrode 35 is determined.

Therefore, the G3 electrode 3 is closest to the cathode 10 and has a high potential difference.
3 and the G2 electrode 12 electrode supporter 18 is set to be as large as possible than when the G3 electrode is divided into equal parts. The path becomes larger, and even if the processing voltage is increased during high-voltage processing, excessive leakage current due to dielectric breakdown between the electrodes will not flow into the cathode IO and damage the cathode IO, so the withstand voltage characteristics are extremely good. Become. On the other hand, G3 electrode 33
and G4 electrode 34, G4 electrode 34, and G5 electrode 35, the mutual spacing between the supports Cz and Cx is also selected to be larger than the spacing between the supports when they are divided into equal parts in the conventional case. The quality is higher than that.

In the above explanation, the main electron lens is an in-line type electron gun electrode structure, but it can also be applied to a delta type electron gun electrode structure in which the main electron lens has an integrated electrode, or a main electron lens focusing method can be applied. is not limited to the above-mentioned method (in short, it can be applied to all electron gun electrode structures composed of a plurality of main electron lenses and a combination of closed cylindrical resistive electrodes that form multiple electron beams). Needless to say.

[Brief explanation of drawings]

Figures 1 and 2 are a front view and a side view of an in-line electron gun electrode structure equipped with a conventional multi-stage focusing electron lens, respectively;
FIG. 3 is a sectional view taken along the line AA' shown in FIG. 1, and FIGS. 4 and 5 are side views of an electron gun electrode structure showing a reference embodiment and a second embodiment of the present invention, respectively. lO: cathode structure; 11: G1 electrode; 12: G2 electrode; 13-, 1: L, 2 L, 23
-*, 33-1n33-z: G3 electrode i 14-+
, 14-t, 24-r. 24-z, 34-1.34-! : G4 electrode; 15th season. 15-z, 25-+, 2.5-z, 35
: G5 electrode; 16°26: G6 electrode; 18: Electrode supporter; 19: Insulator support rod. Figure 4 Procedure amendment (method) 1. Indication of case 1990 Patent Application No. 205547 2. Title of invention Electron gun electrode structure for cathode ray tube 3.
Relationship with the person making the amendment Applicant: 5-7-1 Shiba, Minato-ku, Tokyo (423) Representative: Tadahiro Sekimoto 4゜, NEC Corporation Telephone: Tokyo (03) 3454-1111 (Odai) representative)(
Contact information: NEC Corporation Patent Department) 6. Drawings of the specification to be amended 7. Contents of the amendment

Claims (1)

[Claims] Electrically and structurally common, it has a closed end face with a plurality of electron beam transmission holes and a cylindrical side part roughly perpendicular to the closed end face, and a flange-shaped edge for a support on the cylindrical side part on the open end side. A uni-potential focusing type electron gun electrode structure in which an electron lens is formed by opposing each other to a first and second integrated electrode pair, each of which is formed by overlapping two closed cylindrical electrodes with a flanged edge. In the axial length of the two closed cylindrical body electrodes forming the first integrated electrode pair closest to the cathode, the length on the side closer to the cathode is made longer than the opposite side, and 2
An electron gun electrode assembly for a cathode ray tube, characterized in that the length in the axial direction of the two closed cylindrical body electrodes forming the integrated electrode pair is set longer on the side closer to the cathode than on the opposite side.