JPS6132942A - Electron gun - Google Patents

Abstract

PURPOSE:To prevent a resistor from being destroyed by heat by making the thickness of at least one insulating support body thinner than that of the other electrode support body and insulating a fully high resistor in this section. CONSTITUTION:A first electrode support body 2a is thicker than a second electrode support body 2b and fully fixes and holds each electrode. A second electrode support body 2b is thinner than a first electrode support body 2a and gently fixes and holds each electrode. In addition, a thin plate type resistor 3 is mounted on the rear of the second electrode support body 2b and each electrode potential of a third grid 13 and a fourth grid 14 is assigned as the split potential resulting from the resistor 3 of high voltage Eb applied to a convergence electrode 17 and a fifth grid 15. Consequently, the resistor can secure ample surface area. As a result, even if such fully high current that the effect of undesired current like inter-electrode leak current, etc. can be ignored is applied to the resistor, the resistor can be prevented from generating heat and being destroyed.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to the structure of an electron gun for focusing at least one, preferably more, electron beam.

[Technical background and problems of the invention]

A cathode ray tube is equipped with at least one electron gun.
This electron gun forms an electron beam spot on a predetermined target, and one of the extremely important factors that determines the performance of a cathode ray tube is the electron beam diameter on the target. It goes without saying that a smaller spot diameter is more desirable, but this spot diameter is determined by the performance of the electron gun.In general, an electron gun consists of a part that generates an electron beam and a main lens that accelerates and focuses the electron beam. One effective means of improving the performance of an electron gun is to improve the performance of the main lens part.

Most of the main lens parts are electrostatic lenses, which are formed by arranging a plurality of electrodes having openings coaxially and applying a predetermined potential. There are several types of such electrostatic lenses depending on the electrode configuration, but basically they are made by increasing the electrode aperture diameter to form a large-diameter lens, or by increasing the distance between the electrodes to achieve a gradual potential change. Lens performance can be improved by forming a long focal length lens. However, since electron guns for cathode ray tubes are generally used enclosed in a thin glass cylinder, the aperture of the electrodes, that is, the diameter of the lens, is physically limited, and then the focused electric field formed between the electrodes is The distance between the electrodes is limited to avoid being affected. Particularly when a plurality of electron guns are used in a line, such as in a color picture tube, the smaller the electron gun spacing Sg is, the easier it is to concentrate the plurality of beams, and it is also advantageous in terms of power in the wound. Therefore, the openings in the electrodes have to be made even smaller. Therefore, a practical method for increasing the distance between the electrodes was proposed in Japanese Patent Publication No. 55-4867 for an electron gun for color picture tubes having a pi-potential type lens in the main lens section.
This is shown in Publication No. 4.

The electron gun shown in Japanese Patent Publication No. 55-48674 has a first gun having the same aperture. between the second two electrodes and the first. A plurality of electrodes having the same openings as the second electrode are arranged at regular intervals, a small resistor is installed near these plurality of electrodes, and the first. These plural potentials are supplied as resistance division potentials of the second electrode potential, and this (: therefore, the first
The objective is to achieve a gentle potential change from the electrode to the second electrode and obtain a high-performance lens equivalent to a lens in which the distance between the first electrode and the second electrode is simply increased. However, in such an electron gun, undesirable currents such as leakage current between the electrodes and current due to electron beam impact on the electrodes flow through the resistor and change the predetermined electrode potential, so it is difficult to obtain the predetermined divided potential. Therefore, it is necessary to make the current flowing through the resistor sufficiently large. However, if the current is increased, the power consumption by the resistor increases, causing the resistor to heat up and break down. In order to prevent this, the surface area of the resistor must be made sufficiently large to suppress the heat generated by the resistor due to radiant heat. However, in the electron gun mentioned above, the resistor placed near the multiple electrodes is too small, so it is necessary to ensure a sufficient surface area. - [Object of the Invention] In view of the above-mentioned points, the object of the present invention is to provide a highly practical electron gun that does not cause thermal breakdown by having a resistor of sufficient size for supplying the electrode potential of the electron gun. Our goal is to provide the following.

[Summary of the invention]

In the present invention, the thickness of at least one insulating support of a plurality of electrode supports for supporting each electrode of an electron gun is made thinner than the thickness of the other electrode supports to provide a sufficiently large thickness for this part. The above object is achieved by inserting a resistor.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the drawings.

Fig. 1 is an example of an electron gun for a color picture tube embodying the present invention, Fig. IJ2 is a view of the lower part of the electron gun from line A-A in Fig. FIG.

In FIGS. 1 and 2, an electron gun (1) includes a plurality of electrodes (described later) and two electrode supports (2a) that support the electrodes.
(2b) and a resistor (3) for supplying at least one electrode potential. the plurality of electrodes are red;
Eight electron beams (4
It has an integrated structure with cathodes (6) arranged in a row containing eight heaters (5) for generating ) and predetermined electron beam passage holes bored at positions relative to these eight cathodes. (unitized structure) of the first grid αυ, second grid α, eighth grid (13, fourth grid (
14), 5th grid a-bar and convergence electrode (
I7), which are implanted and fixedly supported in this order on the two electrode supports (2a) and (2b), respectively. The first grid a and the second grid α are plate-shaped electrodes arranged close to each other, and the eighth grid α is composed of two cup-shaped electrodes (28a) arranged close to the second grid α.
(28b), the fourth grid I consists of two cup-shaped electrodes (24m), (24b) arranged at a predetermined distance from the illumination grid 8, and the fifth grid 9 consists of the fourth grid A4. Two cup-shaped electrodes (25a) placed a predetermined distance apart.

(25b), and the convergence electrode aη is one cup-shaped electrode (27a) fixed by welding to the fifth grid α field.
). In addition, the two electrode supports (2a), (
2b), the first electrode support (2m) is thicker than the second electrode support (2b) and holds each electrode sufficiently fixed, and the second electrode support (2b) is thicker than the second electrode support (2b), and the second electrode support (2b) Support (2a
) It is thinner and each electrode is lightly fixed and held. In addition, a thin plate-shaped resistor (3) is attached to the dorsiflexion of the second electrode support (2b).
is installed. A valve spacer Q8 is attached to the convergence electrode Q7) for applying about 25 groups of anode high voltages E to an anode terminal (not shown). Such an electron gun (1) is provided with a narrow gap of 1.5 mists. A stem pin (A) is provided at the bottom of the neck al, and this stem pin (A) fixedly supports the electron gun (1) and also transmits each grid potential other than the convergence electrode η and the fifth grid a9 through the stem pin (1). It can be supplied from outside. The resistor (3
) is connected and fixed to the convergence electrode a7) via a connector GO, and the other end is connected and fixed to the stem pin side by a connector (51), and is connected to a variable resistor (52) externally.
)It is connected to the.

In addition, terminals (5B
).

(54) are provided, and the connectors (56),
4th grid I, 8th grid a3 via <57)
are connected to each. Therefore, electrically, the fourth factor is the resistor (3) of the high voltage E applied to the 8th grid α locus, the 4th grid (each electrode potential from 1 to the convergence electrode α7), and the 5th grid a9. It is given as a divided potential by .

In the above electrode configuration, each electrode potential is, for example, as follows. The cathode (6) is kept at a cut-off voltage of approximately 150v, to which a respective modulation signal is applied.

The ground potential is applied to the second grid aυ, about 700 V is applied to the second grid a, and about 25 KV is applied to the fifth grid (L!19 and convergence electrode (17)). OKV, 4th grid α4 is approximately 16
KV is applied as a divided potential of about 25 Kv by the resistor (3). It is well known that by adopting such an electrode configuration, a lens with a long focal length can be formed, electro-optical magnification and spherical aberration can be reduced, and lens performance can be significantly improved.

At this time, the resistance of the resistor (3) is approximately 1000 MΩ, so the current flowing through the resistor (3) is 25μ, and the power consumption by the resistor is approximately 625 mWatt.At this time, the resistor (3) is destroyed due to heat generation. According to experiments, in order to avoid this, a heat sink with a surface area of at least 1000 mm is required.As mentioned above, the electron gun is enclosed in the neck 0 of a thin glass cylinder. It is difficult to obtain the above surface area with a short resistor such as the one shown in the figure.Therefore, it is desirable to use a sufficiently long plate-like resistor, but there is no room for it in the neck of a normal electron gun. By making at least one of the resistors thin and placing the resistor in the space created in this way, a sufficiently long resistor can be used, and the resistor (or heat sink) can be This makes it possible to secure a sufficient surface area.Therefore, even if a large enough current is applied to the resistor so that the effects of other undesirable currents such as leakage current between electrodes can be ignored, the resistor will heat up and break down. That will no longer be the case.

FIG. 2 is a view taken from line AA in FIG. 1 to the stem pin side, and the cup-shaped electrode (25b) of the fifth grid aω has eight electron beam passing holes (85a) and (85b).

(85e), and the first electrode support (2a
) is thicker than the second electrode support (2b) and the fifth grid (
The first strap C31) of the electrode (25b) is embedded. In addition, the second electrode support (2b)
The second straps of the fifth grid (19 electrodes (25b)) are embedded thinner than the electrode support (2a).

At this time, the first strap 01) and the second strap G
The lengths of the straps are set to be different, and the first strap 01 is longer than the second strap 01 and is firmly implanted and fixed to the first electrode support. A thin plate-shaped resistor (3) is placed on the dorsiflexion of the second electrode support (2b). As shown in Fig. 8, such a resistor is made by coating a resistive material (102) on a thin flat ceramic substrate (101), attaching an electrode terminal (10B) at an appropriate position, and making it thin except for this terminal part. It can be manufactured by blowing a glass film (104). As the above-mentioned resistive material, materials mainly composed of oxides of paddium or ruthenium are preferred, and a mixture of ruthenium oxide and glass is particularly preferred.

Detailed specifications of the above embodiments include, for example, neck inner diameter 181
111. Y-axis diameter of cup-shaped electrode: approx. 81m% X-axis diameter: approx. 1611m% Length of first strap: approx. 2.5tx
s.

The length of the second strap is approximately 1. gsm+, the thickness of the first electrode support made of glass is approximately 3.5+ m, and the width is approximately 8.51 m.
111, length approximately 45 Mll, second electrode support thickness approximately 2.0 mm, width approximately 8.5 m, length approximately 45 mm, resistor thickness approximately 1.8 m+, width 6.0 Dew, length approx. 7011
1111, the surface area is approximately 104011111, and the total resistance value is approximately 1000 MΩ. With the above configuration, the resistor can have a sufficient surface area and a place for installing it in the neck can be secured, so that a desired electron gun can be obtained.

In the above embodiment, a resistor is coated on a ceramic substrate as a resistor, but the present invention does not need to use a ceramic substrate, and a glass substrate or an insulating film may be used. It may also be used as a resistance material. As the insulating film, for example, a polyimide film (for example, Kapton) having a thickness of 50 μm to 250 μm is suitable, and the resistive material placed on the insulating film can be further coated with a polyimide film. When such an insulating film is used as a substrate, the thickness of the resistor is extremely thin, so it is very preferable to place the resistor in a small gap between the inner wall of the neck and the electron gun.

Further, in the above embodiment, the resistor is one continuous resistor, but the present invention is not limited to this, and it goes without saying that the resistor may be divided into a plurality of resistors.

Furthermore, although the above embodiment describes an electron gun using two electrode supports, the present invention is not limited to this, and the present invention also applies to an electron gun using multiple electrode supports, such as eight or four electrode supports. Applicable.

Although the main lens portion of the above embodiment shows a pi-potential type lens consisting of a third grid, a fourth grid, a fifth grid, and a sixth grid, the present invention is not limited to this. The potential of one side of the shaped lens can be supplied by resistor division, or the electrode potential of other unipotential lenses, geodora potential lenses, Beriodikbotenkull lenses, tripotential lenses, and other electron lenses can be supplied. The present invention is applicable as long as it is supplied by resistance division.

Further, in the above embodiment, the three electron guns are integrated in a row in the horizontal direction, but the present invention is not limited to this, and the present invention is not limited to this. It goes without saying that the present invention can be applied to a structure in which several electron guns are arranged or a single electron gun structure.

〔Effect of the invention〕

As described above, according to the present invention, in an electron gun in which the main lens portion is formed by an electrostatic lens, and in which at least one electrode potential is supplied as a resistance-divided potential of a relatively high potential, each of the electron guns The surface area of the resistor (or heat sink) is reduced by making at least one of the plurality of electrode supports for fixing and holding the electrode thinner than the other electrode supports to provide a place for installing the resistor. can be made sufficiently large, so even if a large current is passed through the resistor so that undesired currents such as interelectrode reeler current can be ignored, the resistor will not heat up and break down, making it a highly practical electron gun. can be provided.

In addition, by supplying the medium-high potential of the electron gun's electrodes from the outside through the stem bin at the bottom of the neck, but instead by dividing the potential by a resistor, the reliability of the withstand voltage around the stem is improved, and the internal voltage of the picture tube is improved. It is also possible to protect the picture tube operating circuit by reducing undesirable spark currents.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the electron gun of the present invention;
Fig. 2 is a schematic cross-sectional view taken along line A-A in Fig. 1, Fig. 3 is a partially cutaway perspective view showing the main parts of the resistor used in Fig. 1, and Fig. 4 is the same as Fig. 1. FIG. 2 is a circuit diagram showing the electrical configuration of an electron gun. (1)...Electron gun (2a), (2b)...Insulating support (3)...Resistor (1o1)...Ceramic substrate (to2)...Resistor (1Oa)...・Electrode terminal (104)...Glass coating agent Patent attorney Kensuke Chika (and 1 other person) 1st
Figure ρ Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A main lens section consisting of at least an electron beam generating section, a plurality of electrodes for focusing the electron beam on a predetermined target, a plurality of electrode supports for supporting these electrodes, and a main lens section disposed near these electrodes. In an electron gun including at least one resistor, at least one of the plurality of electrode supports is thicker than the other electrode supports, and An electron gun characterized in that the resistor is thinner than the thickness of other electrode supports, and the resistor is arranged near the electrode supports.