JPS61133536A - Electron gun - Google Patents

Abstract

PURPOSE:To mount a main lens with large diameter on an electron gun without being influenced by the potential at the inside wall of the neck by dividing a resistor available for electron gun into two parts at the intermediate point to connect it to the auxiliary electrode and forming the structure in which any resistor doesn't exist in the back side of the auxiliary electrode. CONSTITUTION:An electron gun includes a first electrode 15 having the integrated structure, a second electrode 16, third electrode 17, fourth electrode 18, convergence cup 19 and an auxiliary electrode 20. A resistor 12 comprises a first resistor 12a connected and fixed with a stem pin 23 and the member 20a of the third electrode 17 on the auxiliary electrode 20, and a second resistor 12b connected and fixed to the side member 20b of the fourth electrode 28 on the auxiliary electrode 20 and the side wall of the convergence cup 19. Therefore, the space between the third electrode 17 and fourth electrode 18 can be taken wide and as a result, an electrostatic lens with long focus distance can be formed.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an electron gun.

[Technical background of the invention and its problems]

A cathode ray tube is equipped with a sub-gun inside, and the electron beam from this electron gun is focused onto a predetermined target. One of the extremely important factors that determines the performance of this cathode ray tube is the spot diameter of the electron beam on the target.Of course, the smaller the spot diameter, the better. It is decided by the performance of

In general, an electron gun consists of an electron beam generator that emits an electron beam, and a main lens that accelerates and focuses the electron beam.One effective way to improve the performance of an electron gun is to The goal is to improve performance.

Most of this main lens part is a static lens, and this electrostatic lens has a plurality of electrodes having an electron beam hole arranged coaxially, and a predetermined voltage is applied to these H°C poles. formed by

There are several types of such electrostatic lenses depending on the market price structure, but basically they are made by increasing the diameter of the electron beam passage hole to form a large-diameter lens, or by increasing the distance between the electrodes. Lens performance can be improved by forming a long focal length lens with a gradual potential change.

However, since electron guns for cathode ray tubes are generally enclosed in a narrow glass cylinder or neck, the diameter of the electron beam passage hole in the electrode forming the main lens, that is, the lens diameter, is physically limited. Furthermore, the distance between the electrodes is limited in order to prevent the focused electric field formed between the electrodes from being influenced by other electric fields.

In particular, when multiple electron guns are used in a line, such as in a color picture tube, the smaller the distance between the electron guns (8 g), the easier it is to converge multiple electron beams, and it is also advantageous in terms of deflection power. It is.

Therefore, while reducing the electron gun spacing Sg, the electron beam passing hole should be made as large as possible, and the distance between the electrodes should be sufficiently widened. Electron guns with electrodes are being considered.

In such an electron gun, it is necessary to eliminate the influence of the electric field of the auxiliary electrode itself, so the aperture diameter of the auxiliary electrode must be set sufficiently large. Therefore, it is necessary to make the aperture diameter of the auxiliary electrode large to the same extent as the neck inner diameter and to make the distance between the electrodes sufficiently wide to provide a high-performance electron gun.

However, in the above-mentioned electron gun, in order to make the axial potential distribution of the main lens as gentle as possible, it is considered that the potential applied to the auxiliary electrode is preferably set to an intermediate potential between the potentials applied to the counter electrode.

In this case, for example, in the case of a pi-potential square, a high voltage of about 7KV to 8KV is applied to the cathode side electrode, that is, the focus electrode, and a high voltage of 25KV to 3QKV, which is equal to the anode voltage, is applied to the opposite electrode and applied to the auxiliary electrode for operation. The voltage will be approximately 16KV to 19KV.

In conventional electron guns, the anode voltage is applied from the anode button of the funnel through the internal conductive film, and the voltage below the focus voltage is supplied from the stem side.

This is because the voltage that can be applied from the stem is a problem of withstand voltage.
It is considered that the maximum voltage is 1 QKV at most, and therefore the high voltage of 16KV to 19KV that must be applied to the auxiliary electrode cannot be supplied from the stem side. Therefore, a structure in which the voltage applied to the auxiliary electrode is self-supplied inside the picture tube via a resistor may be considered.

That is, a resistor may be disposed near the electron gun, one end of the resistor may be used as an anode voltage, the other end may be used as a focus voltage, and the intermediate point thereof may be connected to an auxiliary electrode. This resistance value generally requires a value of several 100 MΩ to several 1000 MΩ, and therefore the dimensions of the resistor must be relatively large.

On the other hand, in the above-described electron gun structure, it is necessary to make the auxiliary electrode as large as possible so that it is approximately equal to the inner wall of the neck.

Therefore, when a resistor is placed near the electron gun, there is a problem in that there is virtually no space in which to place the resistor due to mechanical size limitations.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and
through the resistor by means depending on the structure of the auxiliary electrode.
The object of the present invention is to provide an electron gun that can supply a predetermined voltage to this auxiliary electrode.

[Summary of the invention]

That is, in the present invention, the resistor used in the electron gun is divided into two at the midpoint where it is connected to the auxiliary electrode, and the structure is such that there is no resistor behind the auxiliary electrode. It is an object of the present invention to provide an electron gun that is capable of constructing a large diameter main lens that is not often used.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

That is, the electron gun QO enclosed in the neck (1) has a plurality of electrodes, an insulating support (Ll) generally called bead glass that supports and fixes these electrodes, and this insulating support (Ll).
A plurality of resistors (12a) disposed near the (11)
2b).

The above-mentioned electrodes impinge on the red, green, and back colored phosphor layers3.
Three heaters (13
) are arranged in a row, and predetermined electron beam passing holes are bored at positions corresponding to the three cathodes α, respectively, and the first one has an integrated structure.
It consists of electrodes (1, 51, second electrode 6), third electrode (1η), fourth electrode α mallet, convergence cup (19), and auxiliary electrode (20) having one large opening.

The first electrode α and the second electrode (Lυ are arranged close to each other,
The third electrode aυ is a combination of two cup-shaped electrodes, and the fourth electrode α mark is a combination of two cup-shaped electrodes arranged a predetermined distance away from the third electrode α. It becomes.

In addition, the auxiliary electrode (20) is the third electrode (L7) and the fourth electrode a.
It consists of a combination of cup-shaped electrodes (20a) and (20b) with one large opening arranged to completely cover the interval between the barrels, and the convergence cup σ is the fourth
It consists of a cup shape that is welded and fixed to the electrode bracket, and a plurality of pulp spacers 21) are attached to the outer wall.

This valve spacer circle is an internal conductive film (22
1 and is in contact with the internal conductive film (22
, an anode voltage is applied to the convergence cup σ■ and the fourth electrode (18) via the pulp spacer (2+).

The resistor (one consists of a first resistor (1za) and a second resistor (12b). One end of the first resistor (12a) is fixed to the stem pin @, and the other end is fixed to the auxiliary electrode. (20
) is connected to and fixed to the member (20a) of the third electrode (17). There is a terminal 041 approximately in the middle of this first resistor (12a), and the terminal C? 411d is connected to the third electrode α. Further, the second resistor (12b) has one end connected to the auxiliary electrode (fourth electrode (I8) side member (20) of
b) is connected and fixed to the other end ij convergence cup α
It is connected and fixed to the side wall of 1.

The stem pin (
A variable resistance element (c) is connected to 231 outside the picture tube.

By adopting such a configuration, an electrically equivalent circuit as shown in Fig. 3 is obtained, and the anode' voltage is connected to the resistor (12b).
) (12a) and the variable resistance element (2ω), and are supplied to the auxiliary electrode (20) and the third electrode η, respectively.

With the above configuration, the following voltages are supplied to each electrode.

That is, a cut-off voltage of approximately 150 cm is applied to the cathode (L4) from the stem pin, and a modulation signal is added to this. 1'a1 pole (L is grounded through the stem pin,
The second electrode (approximately 70 mm is connected to 161 through the stem pin)
0V is applied. A resistor (12a) is provided at the third electrode αη.
Approximately 7 KV is applied through the terminal c241. Fourth
The electrode θ has an inner conductive film (22
1. Pulp spacer (211, convergence spacer 7'
(Approximately 25KVO high voltage is applied through L9. As a result, the auxiliary t i (201 has a resistor (12b) (
A voltage of approximately 16 KV is applied via 12a).

With this electrode configuration, the distance between the third electrode (17) and the fourth electrode (country) can be widened, resulting in the formation of an electrostatic lens with a long fishing distance, improving lens magnification and spherical aberration. This significantly improves lens performance.

Various structures are known in which this resistor is placed near the electron gun and a predetermined voltage is applied using electrodes. This is disclosed in Publication No. 55-38484. However, all of these consist of one resistor, and this resistor is fixed behind the insulating support member (Ll), or the resistor is embedded inside the insulating support member U, and each Since the size of the electrodes, that is, the external shape in the plane direction perpendicular to the tube axis, is almost the same, it was not necessary to divide the resistor in the tube axis direction. In contrast, the electron gun of the embodiment requires an auxiliary electrode in the main lens portion, and the size of this auxiliary electrode (2G) must be placed as close to the inner wall of the neck as possible.

That is, as shown in FIG. 2, the distance between the inner wall of the neck αD and the auxiliary electrode is approximately one square. On the other hand, as shown in Figure 4, the voltage dividing resistors (12a) and (12b) are made by coating the ceramic substrate 01) with the resistive material (3) in a meandering manner, and then forming a resistor by sintering or the like. It is coated with a glass coating □□□, and the terminal C34 is attached to the desired part.
It has a structure in which the thickness (tl) is about 2 mm, and the width W is about 5 cocoons, so it is no longer necessary to use the final electrode, for example, the fourth electrode (one mark and one for each person). It becomes impossible to arrange a resistor. Therefore, when considering one resistor as a standard, this resistor is divided into two at the midpoint where the auxiliary electrode (20) should be connected, and the auxiliary electrode (20 ) is an extremely effective means.

When the resistor is divided into K parts (12b) and (12a) in this way and applied to the electron gun of the present invention, the following effects can be obtained.

First, the resistor can be arranged in a structure that does not depend on the shape of the auxiliary electrode.

Second, since it is divided at the midpoint, the electrical equivalent circuit is the same as one.

Thirdly, the first resistor (12a) and the second resistor (12b
) are independent, so there is a range in the set value of each resistance value, that is, the size of the resistor.

In the embodiment, the case where the auxiliary electrode (20) has an oval shape as shown in FIG. 2 has been described, but the present invention is not limited to this.

Next, an embodiment of the present invention will be explained with reference to FIG. However, the same reference numerals indicate the same parts and will not be particularly described.

That is, in this embodiment, auxiliary 1! The L pole piece is circular along the inner wall of the neck, and therefore the insulating support member (11)
is divided into two parts in the tube axis direction, and includes an insulating support member (11a) and an insulating support member (11a).
lb), it can also be a more effective means.

In addition, although the pi-potential type electron gun has been described in these embodiments, an electron gun having a compound main lens called a Fordra potential type electron gun having another main lens may also be used.
It can be applied as is. That is, the main lens parts of this type of electron gun are spaced apart by a predetermined distance, and the auxiliary electrode is disposed at a position corresponding to this space.

The voltage to be applied to the auxiliary electrode may be supplied by dividing the resistor into two, as in the previous embodiment.

Further, in the embodiment, an in-line type electron gun has been described, but it goes without saying that the same concept can be applied to a delta type electron gun.

〔Effect of the invention〕

As described above, according to the present invention, the focusing performance can be significantly improved without increasing the electron beam interval, that is, while maintaining good convergence characteristics, and furthermore, the voltage to be supplied to the auxiliary electrode can be adjusted to the size of the auxiliary electrode. An electron gun capable of resistive voltage division can be provided with an independent structure.

[Brief explanation of drawings]

1 to 4 are diagrams showing an embodiment of the electron gun of the present invention, in which FIG. 1 is a schematic side view, FIG. 2 is a cross-sectional view of FIG. 1 taken along the N- entry line, FIG. 3 is an equivalent circuit diagram of the resistor, FIG. 4 is a partially cutaway perspective view of the resistor, and FIG. 5 is a side view showing another embodiment of the electron gun of the present invention.

Claims (2)

[Claims] (1) An electron gun consisting of an electron beam generating section that emits an electron beam and a main lens section that focuses the electron beam on a predetermined target, the main lens sections being arranged so as to be separated by a predetermined distance. It consists of at least two electrodes and an auxiliary electrode arranged to substantially cover this predetermined interval, and an anode voltage is applied to the electrode constituting the main lens portion and the auxiliary electrode at a predetermined value via a resistor. 1. An electron gun characterized in that the resistor is divided into two by the auxiliary electrode in the tube axis direction and is disposed near the electrode. (2) The electron gun according to claim 1, wherein the resistor is electrically connected via an auxiliary electrode.