JPH0146986B2 - - Google Patents

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. The present invention relates to an electron gun electrode assembly with an integrated electrode forming an electron lens.

Simplify the assembly work of the electron gun electrode assembly, improve assembly accuracy, or reduce the volume occupied by the electron gun electrode assembly due to the reduction in the diameter of the neck of the glass envelope in which the electron gun of a color cathode ray tube is sealed. As a means of achieving this, an electron gun electrode assembly is generally used which is electrically and structurally common and includes an integrated electrode for each electron beam path forming a substantially separate or common electron lens. 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 electrode assembly is used which is equipped with a multi-stage focusing electron lens that combines multiple electron lenses instead of just one main electron lens. However, depending on the electrode configuration, there are some electrodes whose axial length is the same as or less than the gap between opposing electrodes, and the heat capacity of these electrodes is significantly smaller than that of other electrodes. The mutual distance between electrode supports may also be comparable to the gap between opposing electrodes. During operation of the electron gun, different high voltages are applied between the electrodes, and a large potential difference occurs between each opposing electrode, so the voltage resistance characteristics between the electrodes must be good. Therefore, during the cathode ray tube manufacturing process, high voltage treatment is performed in order to improve the withstand voltage characteristics between the electrodes where the above-mentioned high potential difference occurs, but there is a large difference in heat capacity between multiple electrodes, and the electrode support If there is a large difference in the mutual distance between the electrodes, a sufficiently high voltage cannot be applied between the electrodes, and the withstand voltage characteristics between the electrodes will deteriorate significantly.

Figures 1 to 3 show one of the conventionally used electron gun electrode structures equipped with multistage focusing electron lenses.
This will be explained according to the diagram. Figures 1 and 2 show a conventional in-line type in which cathodes are arranged on the same plane, electrically insulated from each other and equally spaced apart, and the main electron lens is a bipotential type with three main electron lenses.・A front view and a side view of the electron gun electrode structure 1 which adopts a multi-stage focusing electron lens system in which focus electron lenses are stacked, respectively, and FIG. 3 is A-A shown in FIG. 1.
A cross section is shown.

The electron gun electrode assembly 1 includes cathode assemblies 10 which are insulated from each other and arranged in a line at equal intervals 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. G1, the control electrode
The electrode 11 and the G2 electrode 12, which is an accelerating electrode for the thermionic beam emitted from the cathode, are electrically and structurally common, and each electron beam path is composed of an integrated electrode that forms a substantially independent electron lens. G3 electrode 13 is the first focusing electrode, and the first anode electrode
G4 electrode 14, G5 electrode 15 which is a second focusing electrode,
It is composed of a G6 electrode 16 which is a second anode electrode.

Each electrode has a supporter 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 and fusing the electrodes into each other, the distance between each electrode is maintained and fixed at a predetermined dimension. G4 electrode 14 and G6 electrode 16 are power supply lines 17A
Although not shown, the internal conductive coating is connected to the anode terminal disposed in the funnel-shaped part of the cathode ray tube glass envelope in which the electron gun electrode structure 1 is sealed. A high anode voltage of about 30 KV is supplied, and the G3 electrode 13 and the G5 electrode 15 are brought to the same potential by the power supply line 17B. Although not shown, the anode is connected to the power supply pin of the stem on which the electron gun electrode assembly 1 is supported and fixed. A focused voltage of about 20 to 40% of the voltage is supplied, and 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 10 is diverged from a crossover point formed near the G1 electrode 11 and the G2 electrode 12, and is separated from the G2 electrode 12.
Buri focus formed between G3 electrodes 13
After pre-focusing with the lens, G3 electrode 13 and G4 electrode 14, G4 electrode 14 and G5 electrode 15, G5 electrode 15
The beam is sequentially focused in three stages by three independent bipotential type lenses, which are formed in the gap between the G6 electrode 16 and the main focus lens, and has the smallest beam spot cross-sectional area on the fluorescent surface. The focusing voltages applied to the G3 electrode 13 and the G5 electrode 15, which are focusing electrodes, are adjusted in this manner. The electron beam pre-focused by the pre-focus electron lens is 3
Since the main focus lenses are focused in three stages, the strength of each main focus lens can be weaker than that of a single main focus lens in a conventional electron gun. Therefore, the three main electron lenses can gradually focus the electron beam, and the spherical aberration of the main electron lens system becomes extremely small, so that the electron beam can be focused even when the beam current is large, which is the high brightness screen during cathode ray tube operation. The beam passes through the center of each main electron lens with small aberrations, resulting in a narrowly focused beam, and a high-resolution received image can be obtained on the fluorescent surface even on a high-brightness screen. .

Taking the G5 electrode 15 that constitutes a part of the main electron lens 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 in Figure 3. Three apertures 15 bored as center and both outer electron beam transmission holes
It is a closed cylindrical body that has a closed end face and a cylinder side part that is long in the arrangement direction of R, 15G, and 15B and has a substantially rectangular or elliptical shape that is short in the direction perpendicular to the arrangement direction, and the open end has a closed end face and a cylinder side part. A flanged edge 15A extending at right angles to the cylinder side is integrally formed, and the flanged edge 15A on the long side has a plurality of notches in order to increase the strength of the welding with the insulator support rod 19. A portion 18A is provided at the tip to constitute an electrode supporter 18, and two closed cylindrical body electrodes are overlapped with each other at a flanged edge 15A.

As described above, a high anode voltage is applied to the G4 electrode 14 and the G6 electrode 16, and a medium-high voltage of about 20 to 40% of the anode voltage is applied to the G3 electrode 13 and the G5 electrode 15 as a focusing voltage. That is, G3 electrode 13 to G6 electrode 16
A high voltage anode voltage and a medium-high voltage focusing voltage are periodically applied between the G3 electrode 13 and the G3 electrode 13.
G4 electrode 14, G4 electrode 14 and G5 electrode 15 and G5
Since a large potential difference is generated between the electrode 15 and the G6 electrode 16, the distance between the opposing electrodes and the distance between the supports embedded in the insulating support rod 19 greatly affect withstand voltage characteristics. G3 electrode 13 and G4 electrode 14, G4 electrode 14 and G5 electrode 15, and G5 electrode 1
The larger the inter-electrode spacing _{a1a2a3 of} the 5 and G6 electrodes 16, the better from the viewpoint of withstand voltage characteristics, but if _it is too large, the electron beam path will be undesirably bent due to the influence of external electric field penetration. Therefore, the sizes are selected to be equal and not affected by this effect. On the other hand, the withstand voltage characteristics between the electrode supports 18 of the G3 electrode 13, G4 electrode 14, G5 electrode 15, and G6 electrode 16 depend on the fixed resistance value due to the composition of the insulator support rod 19 and the surface resistance value due to the surface condition, etc. G3 electrode 1
3 and G4 electrode 14, G4 electrode 14 and G5 electrode 15,
It is desirable that the distance A ₁ A ₂ A ₃ between the electrode supports 18 of the G5 electrode 15 and the G6 electrode 16 be as large as possible, so that the shortest leakage current path along the insulator support rod 19 is large. It is determined by the axial length of each electrode determined from the characteristics and the mutual electrode spacing a ₁ a ₂ a ₃ . Normally the above electrode spacing a ₁ a ₂ a ₃ is 0.8 to 1.5 mm
The surface condition of the counter electrode surface can be made to be a clean surface with no problem with withstand voltage during the manufacturing process of the electron gun electrode structure and cathode ray tube, and the cathode ray tube can be used in a high vacuum. Considering that it operates at 50 to 80 KV, it has a withstand voltage characteristic of about 50 to 80 KV, and the size of the electrode spacing is not a big problem in terms of withstand voltage characteristics.In fact, the main factor that determines the withstand voltage characteristics between the electrodes is It can be said that this is the distance between the electrode supports along the surface of the insulator support rod 19.

However, conventionally, the G3 electrode 13, the G4 electrode 14, and the G5 electrode 15 are two closed cylindrical electrodes 13 _-1 , 13 _-2 , whose length is equal to the required axial length.
14 _-1 , 14 _-2 , 15 _-1 , 15 _-2 were formed by overlapping their brim-like edges, so as shown in FIG. 2, G3 electrode 13, G4 electrode 14, G5 electrode 15,
The spacing A ₁ A ₂ A ₃ of each electrode supporter 18 of the G6 electrode 16 has unequal lengths, and depending on the electrode configuration determined by the focus characteristics, the axial length of one electrode may be significantly greater than that of another electrode. becomes shorter (in the case of Figure 2)
G4 electrode 14), the distance A ₁ A ₂ between the electrode supports of the electrode adjacent to this electrode is shorter than the other distance A ₃ , and the electrode support 18 along the insulator support rod 19
The shortest leakage current path formed between the two is long or short. 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 equivalent to 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 leakage current is concentrated during this period, so too much high voltage is applied and high voltage processing is not possible, resulting in poor withstand voltage characteristics.

Furthermore, in the high voltage treatment process mentioned above, the anode electrode
A high voltage several times the anode rated voltage is applied to the G6 electrode 16 and the G4 electrode 14, and the other electrodes, namely the G5 electrode 15 which is a focusing electrode, the G3 electrode 13, the G2 electrode 12, the G1 electrode 11, and the cathode 10 is held at ground potential. _The main electron lens electrode mutual spacing _a1a2a3 is usually about 0.8~ _1.5mm , and the high voltage processing voltage is 50~
As a result, a strong electric field of 50 to 100 MV/m is applied between the main electron lens electrodes, and due to the so-called cold cathode emission effect, the high potential electrodes G6 electrode 16 and G4 electrode 14 are grounded. A cold cathode emission current flows toward the G5 electrode 15 and the G3 electrode 13, which are at the potential. In other words, as shown by arrow B in FIG. 2, the cold cathode emitted electrons are at the ground potential at the G5 electrode 15, and from the G3 electrode 13 to the G6 electrode 1 at a high potential.
6. The electrons will flow into the G4 electrode 14, and will be accelerated at high speed by a strong electric field, and will flow into the G6 electrode 16.
The kinetic energy of the electrons collides with the surface of the electrode opposite to the electrode at ground potential of the G4 electrode 14, and the kinetic energy of the electrons is converted into heat, which continues to heat the electrode during the high voltage treatment period. The electrode surface temperature rises rapidly. In particular, arrow B in Figure 2
As shown in the figure, during the high voltage treatment process, the
G4 electrode 1 sandwiched between G3 electrode 13 and G5 electrode 15
4, electrons collide from the G3 electrode 13 and the G5 electrode 15, heating both sides, twice as much as the G6 electrode 16, which heats only one side. Furthermore, the axial length of the electrode determined from the design dimensions of the main electron lens electrode configuration is significantly shorter than other electrodes and electrode spacing, and the G4 electrode 14 shown in Figure 2 has a significantly higher heat capacity than other electrodes. Because it is small, the colliding electrons heat it up until it becomes red hot, and at the same time, the electrode support part 18 is also red hot, and the local heat causes the insulator support rod 19 to be locally distorted, and as a result, the insulator support rod 19 This may lead to the formation of cracks or breakage, resulting in the electron gun electrode assembly 1 being mechanically and electrically defective. Therefore, the conditions for high voltage treatment are G4, which takes into consideration the prevention of destruction of the insulator support rod 19.
The inter-electrode processing conditions were limited to the G3 electrode 13 and the G5 electrode 15 facing the electrode 14, and therefore the withstand voltage quality was insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an electron gun electrode structure that can perform good voltage resistance treatment between electrodes and has good voltage resistance characteristics.

The cathode ray tube electron gun electrode assembly of the present invention includes a cathode assembly, a control electrode, an accelerating electrode, and two closed cylindrical electrodes having different axial lengths, which are overlapped at the flanged edge for the electrode support. The first focusing electrode, the first anode electrode, and the second focusing electrode formed by the above electrodes, and the second anode electrode made of one closed cylindrical electrode are formed by embedding their electrode supports in an insulator support rod. , are arranged in this order, and the distance between the mutual electrode facing surfaces of the first anode electrode and the first focusing electrode and the second focusing electrode on both sides thereof is the same as that of the second focusing electrode and the second anode electrode. The distance between the electrode facing surfaces is set larger than that of the first focusing electrode, the first anode electrode, and the second electrode.
The minimum distance between the electrode supports of the focusing electrode and the second anode electrode is such that two closed cylindrical electrodes having the same length in the axial direction are overlapped at the flanged edges of the electrode supports to perform the first focusing. An electrode, a first anode electrode, and a second focusing electrode are formed, and the spacing between opposing surfaces of these electrodes is set to be larger than the minimum spacing between the electrode supports.

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 an embodiment of the present invention, and in order to simplify the explanation, the same reference numerals are given to the same parts as in the conventional one.

The electron gun electrode assembly 2 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 the cathode assemblies 10. G1, the control electrode
The electrode 11 and the G2 electrode 12, which is an accelerating electrode for the thermionic beam emitted from the cathode, are electrically and structurally common, and each electron beam path is composed of an integrated electrode that forms a substantially independent electron lens. G3 electrode 23 which is the first focusing electrode, fourth electrode 24 which is the first anode electrode, G5 electrode 25 which is the second focusing electrode,
It is constructed in the same manner as the conventional one with a G6 electrode 26 which is a second anode electrode. Each electrode has a support element 18 formed with a part embedded in an insulating support rod 19, and each support element 1
By embedding the embedded portions of 8 into the two insulator support rods 19 and fusing them, the distance between each electrode is maintained and fixed at a predetermined dimension. As in the past, the fourth electrode 24 and
Although not shown, the G6 electrode 26 is made to have the same potential through a power supply line, and is supplied with a high anode voltage of about 20 to 30 KV. A focusing voltage of ~40% is provided.

However, G3 electrode 23, G4 electrode 24, G5 electrode 2
5. The total length in the axial direction and the electrode structure of the G6 electrode 26 are exactly the same as the conventional one, but the mutual spacing between the electrodes is unequal, and each set of closed cylindrical electrodes constituting each electrode is The axial lengths are of different lengths.

First, the distance between the electrodes is G3 electrode 23 and G4 electrode 2.
4, G4 electrode 24, G5 electrode 25, and G5 electrode 25
The inter-electrode spacing of the G6 electrode 26 is respectively b ₁ b ₂ b ₃ ,
The electrode spacing of the corresponding conventional electron gun electrode structure 1 is a ₁
= a ₂ = a ₃ , the settings are made to satisfy the relationships b ₁ = b ₂ ≧a and b ₁ = b ₂ > b ₃ . In other words, the electrode spacing b ₁ and b ₂ facing the G3 electrode 23, which is at ground potential during high voltage processing during the cathode ray tube manufacturing process, and the G4 electrode 24, which is a high potential electrode sandwiched from both sides by the G5 electrode 25, is changed from the conventional correspondence. G5 electrode 2, which is equal to or greater than the electrode spacing, and is at ground potential.
The electrode spacing b ₃ between the G6 electrode 26 and the G6 electrode 26, which is a high potential electrode facing only one side, is set to be smaller than the electrode spacings b ₁ and b ₂ . However, if the inter-electrode spacings b ₁ and b ₂ are too large, they will be affected by the penetration of external electric fields and undesirably bend the electron beam path in the electron beam passage hole, so they should be selected to a size that will not be affected by this. , b ₃
If it is too small, it will deteriorate the withstand voltage characteristics between the electrodes, so the size is selected so as not to cause this deterioration.

Next, the axial length of each set of closed cylindrical body electrodes from G3 electrode 23 to G5 electrode 25 is not the length obtained by dividing the required axial length into two, but two closed cylinders with different lengths. Cylindrical body electrodes 23 _-1 , 23 _-2 , 24 _-1 , 24
_-2 , 25 _-1 , and 25 _-2 are each formed by overlapping flanges, and a portion of the overlapping flanges serves as a support 18 for the insulator support rod 19. The axial length of each electrode is divided as shown in Figure 4: G3 electrode 23 and G4 electrode 24, G4 electrode 24 and G5 electrode 2.
5. Electrode supporter 18 for G5 electrode 25 and G6 electrode 26
The distance B ₁ B ₂ B ₃ is set so that its minimum value is larger than the length when divided into equal parts, and is set to be approximately equal. That is, a G3 electrode 23 whose length in the electrode axial direction, which is the electron beam traveling direction, is smaller than other electrodes and which faces the G4 electrode 24, which is about the same as the electrode spacing;
In the G5 electrode 25, the axial length of the G3 electrode 23 -2 facing the G4 electrode ₂₄ of the G3 electrode 23 is calculated as the G2 electrode 1
G3 electrode 23 facing 2 is divided so that it is larger than _-1 , and facing G4 electrode 24 of G5 electrode 25
Divide the axial length of G5 electrode 25 _-1 to be larger than G5 electrode 25 _-2 , and divide the electrode supporter 18 intervals.
B ₁ B ₂ is set to be larger than the axial length of each electrode divided equally, and the G4 electrode 24 is also set with the support spacing as much as possible.
It is divided into G4 electrodes 24 _-1 and 24 _-2 having unequal lengths so that B ₁ B ₂ are equal. Also, with G5 electrode 25
The axial division ratio of the G5 electrode 25 is taken into consideration so that the support spacing B ₃ of the G6 electrode 26 is also approximately equal to the other spacing B ₁ B ₂ .

As described above, according to the embodiment of the present invention, the axial lengths of the electrodes constituting the main electron lens are set to different lengths, and the axial length of the electrodes is equal to or smaller than the gap between the opposing electrodes. high voltage is applied at
G3 electrode 23 and G5 facing G4 electrode 24 from both sides
As a result of setting the electrode spacing distances b ₁ and b ₂ with respect to the electrodes 25 to be larger than the electrode spacing distance b ₃ of the G5 electrode 25, which faces only one side of the G6 electrode 26 to which a high voltage is applied, the axial direction of each closed cylindrical body electrode The electrode support spacings B ₁ , B ₂ , and B ₃ , where a higher potential difference occurs than when the length is equally divided and the spacing between opposing electrodes is made equal, are set as large as possible and approximately equal. Therefore, the shortest leakage current path formed between the electrode supports 18 along the insulator support rods 19 is as large as possible and approximately equal, and is sufficient to withstand the high voltage applied during cathode ray tube operation. In addition, in the high-voltage processing process during the cathode ray tube manufacturing process, even if the applied high-voltage processing voltage is increased, excessive concentration of leakage current to the shortest path among the shortest leakage current paths can be prevented, and the processing voltage can be increased. It can be made big. On the other hand, G3 electrode 23 and G5 electrode 2 which are at ground potential during high voltage processing
The G4 electrode 24, which is held at a high potential by being sandwiched between _two electrodes _No. Opposite electrode spacing b ₃ with G6 electrode 26
Since it is set larger, the G3 electrode 23 and
The electric field intensity between the G4 electrode 24 and the G4 electrode 24 and the G5 electrode 25 can be made weaker than the electric field intensity between the G5 electrode 25 and the G6 electrode 26. Therefore, G4 electrode 24 to G3 electrode 23, G5 due to the cold cathode emission effect due to a strong electric field.
The cold cathode emission current flowing into the electrode 25 is the G6 electrode 2.
6 to the G5 electrode 25. That is, it is released from the G3 electrode 23 and the G5 electrode 25.
The amount of electrons colliding with the surface of the G4 electrode 24 and their kinetic energy are both released from the G5 electrode 25.
Even if the heat capacity of the G4 electrode 24 is significantly smaller than that of the G6 electrode 26, it is smaller than the amount and kinetic energy of the electrons colliding with the surface of the G6 electrode 26.
By increasing the high voltage processing voltage, the G4 electrode 24 will not be abnormally heated and become red hot.
This eliminates the possibility of causing cracks in the insulator support rod 19 that could lead to destruction due to localized heat from the electrode supporter 18. Therefore, the high voltage processing conditions can be matched between all electrodes by making the mutual spacing between the electrode supports, which causes a high potential difference, as large as possible and making them approximately equal, and by making the mutual spacing between the electrodes unequal. The high processing pressure can be increased, and the withstand voltage characteristics between the electrodes are significantly improved.

In the above explanation, an electron gun electrode structure consisting of four main electron lens electrodes has been described. However, in the case of an electrode structure with four or more electrodes, a high voltage anode voltage and a medium-high voltage focusing voltage are alternately and periodically applied. It goes without saying that the present application can be applied to an electron gun electrode structure.

Further, in the above description, an in-line type electron gun electrode assembly including an integrated electrode has been described, but it goes without saying that the present invention can also be applied to a delta type electron gun.

[Brief explanation of drawings]

1 and 2 are a front view and a side view, respectively, of an in-line electron gun electrode structure equipped with a conventional multi-stage focusing electron lens, and FIG. The figure shows a side view of an in-line electron gun electrode structure equipped with a multi-stage focusing electron lens, showing one embodiment of the present invention. 10... Cathode structure, 11... G1 electrode, 12...
...G2 electrode, 13 _-1 , 13 _-2 , 23 _-1 , 23 _-2 ...
G3 electrode, 14 _-1 , 14 _-2 , 24 _-1 , 24 _-2 ...
G4 electrode, 15 _-1 , 15 _-2 , 25 _-1 , 25 _-2 ...
G5 electrode, 16, 26...G6 electrode, 18...electrode supporter, 19...insulator support rod.

Claims (1)

[Claims] 1. A first electrode structure formed by overlapping a cathode structure, a control electrode, an acceleration electrode, and two closed cylindrical electrodes with different axial lengths at the flanged edge for the electrode supporter.
a focusing electrode, a first anode electrode, and a second focusing electrode;
A second anode consisting of one closed cylindrical electrode is arranged in this order by embedding their electrode supports in the insulator support rod, and the first
The mutual electrode facing distances between the anode electrode and the first focusing electrode and the second focusing electrode on both sides thereof are both set to be larger than the mutual electrode facing distances between the second focusing electrode and the second anode electrode, and The minimum distance between the electrode supports of the focusing electrode, the first anode electrode, the second focusing electrode, and the second anode electrode is such that the two closed cylindrical electrodes having the same axial length are used for their electrode supports. A first focusing electrode, a first anode electrode, and a second focusing electrode are formed by overlapping each other at the flanged edges, and the spacing between the opposing surfaces of these electrodes is set to be larger than the minimum spacing between the electrode supports. A cathode ray tube electron gun electrode structure characterized by: