JPS62217542A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To improve focus characteristics by forming resisting layers in the vicinity of holes of some electrodes among plural electrodes, through which holes electron beams pass. CONSTITUTION:As the material of resisting layers 6, e.g. crystalline lead borate glass is used. Layers of said glass are annularly formed adjacent to holes 7 of the surface of the sixth grid G6 of the fifth grid G5. When a predetermined voltage is applied to the fifth grid G5 having the so-formed resisting layers 6, a predetermined amount of negative electric charge is charged in the vicinity of the resisting layers 6 so that this negative electric charge and the negative electric charge of electron beams are reacted to each other. Thus, it is possible to restrain constituents of electron beams dispersed in a radial direction to substantially reduce the diameter of beam spot, and thereby improve focus characteristics.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a cathode ray tube.

(Prior Art) In general, a cathode ray tube, for example a shadow mask type color picture tube, has a substantially rectangular panel 01 made of glass, a funnel-shaped funnel 0, and a neck 0, as shown in FIG.
3). The inner surface of the panel Ql) is provided with, for example, a striped phosphor screen (b) that emits red, green, and blue, respectively, while the net O■ is provided with a striped phosphor screen (b) that emits red, green, and blue light, while the screen (b) is arranged in a line along the horizontal axis of the panel ω). A so-called in-line electron gun Oe that emits three electron beams θΦ corresponding to , green, and blue is installed inside. Further, a shadow mask θ0 having a color selection function and having a substantially rectangular electron beam passage hole on its main surface is arranged close to and facing the panel 01).

In such a cathode ray tube, the electron beam is required to have a small spora 1 and good focus characteristics in order to achieve high resolution.

By the way, regarding the suppression of the electron beam spot shape due to the divergence of the radial direction component at the time of large current, Japanese Patent Publication No. 55-22
A technique as shown in Japanese Patent No. 906 has been proposed.

That is, in FIG.
11, second grid electrode G12, third grid electrode G13, first
By setting an auxiliary grid electrode G128 in a cathode ray tube equipped with an electron gun consisting of one grid electrode G1/l and distributing a predetermined voltage, the electron beam in the electron gun of the cathode ray tube reached the vicinity of the auxiliary grid electrode G123. At this time, the electron beam is rapidly decelerated and focused very strongly by the electric field of the third grid electrode G13, and as a result, the diffusion angle of the electron beam incident on the main focusing lens becomes very small, suppressing the beam spot diameter at the time of large current and focusing. It improves the characteristics.

(Problem to be solved by the invention) In the above-mentioned cathode ray tube, the applied voltage distribution of the electron gun and the distance between the electrodes are closely related, and in order to improve the focusing characteristics, the voltage distribution and the distance between the electrodes must be adjusted to extremely high precision. Must be configured. Since an auxiliary grid electrode is added, one stem pin, which is an external connection terminal, must be added.

However, this increase in voltage resistance of the stem pin is extremely disadvantageous in terms of voltage resistance, and it is necessary to perform voltage resistance treatment, which causes problems in terms of process and cost.

An object of the present invention is to form a predetermined electrostatic lens between electrodes constituting an electron gun to obtain a desired electron beam.

[Structure of the invention]

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and is directed to a cathode ray tube equipped with an electron gun having at least a cathode and a plurality of electrodes each having an electron beam passage hole. The potential is partially adjusted by forming a resistive layer near the electron beam passage hole of at least some of the plurality of electrodes, and a predetermined static voltage is created between the resistive layer forming electrode and the adjacent electrode. It forms an electron lens to obtain the desired electron beam.

(Function) The present invention forms an electrostatic lens between adjacent electrodes by forming a predetermined resistance layer near the electron beam passage hole of the electron gun electrode of a cathode ray tube. By applying a predetermined voltage to each electrode, the resistive layer is negatively charged and the potential of the resistive layer forming portion changes, forming a desired electrostatic lens and making it possible to obtain the desired electron beam. It is something.

(Example) The first example of the present invention will be described below, for example, in Japanese Patent Application Laid-Open No. 54-726.
This will be explained by applying it to the multiple beam electron gun shown in Publication No. 67@. FIG. 1 is a schematic sectional view of an electron gun to which the present invention is applied.

In Figure 1, the electron gun ■ is attached to an insulating support rod (not shown).
Heater (2B) implanted through the f1 step.

(2G), (2R), cathode (3B), (3G),
(3R), 1st grid (G1), 2nd grid (G2)
), 3rd grid (G3), 4th grid (G4),
Consists of a fifth grid (G5), a sixth grid (G6), and a convergence electrode 0, each consisting of a cathode (3B),
(3G), (31i1) gun shaft (4B), (4G)
The opening for electron beam passage is located at the position corresponding to (4R), and the first grid (G1) and the second grid (G1) are located on the right.
G2), the fourth grid (G4) has a plate shape, the fourth grid (G4) is connected to the second grid (G2) by a conductor and kept at a low potential, and the third grid (G3) and the fifth grid (G5) are each formed of a cylinder with a bottom, connected by a conductor and given a potential of about 7 KV, and the sixth grid (G6) has a bottom for passing the electron beam. It consists of a bottomed cylindrical body with an opening, and a potential of about 25 KV is applied via a convergence electrode 0.

In the above-mentioned electron gun, the third grid of the second grid (G2)
A resistive layer 0 is formed in an annular shape in each of three portions near the electron beam passage hole on the electrode surface on the grid (G3) side.

Next, this resistance layer will be explained in detail.

Figure 2 shows the second grid (G2) and the third grid (G3).
It is a front view seen from the side.

In FIG. 2, (G2) is the second grid, and ▪ is the resistance layer.

Here, for example, crystalline lead borate glass is used as the material of the resistor B0. As shown in FIG. 2, this lead borate glass layer is formed in an annular shape in the vicinity of the electron beam passage hole (2) on the surface of the second grid (G2) on the third grid (G3) side. The formation method is, for example, by dissolving crystalline lead borate glass containing 30% of 5nOz and having an electrical conductivity of approximately 10-7Ω-1m-1 in a butyl acetate alcohol solution containing several percent of nitrocellulose. The molten lead borate glass is applied using a mask spray method. After coating such a layer, it is passed through a furnace with a maximum temperature of about 440'C and a holding time of 35 minutes or more, so that a crystalline lead borate glass layer, ie, a resistance layer 0, can be formed on the electrode surface.

A second grid (
When a predetermined voltage is applied to G2), a negative charge is charged in the vicinity of the resistance layer 0 at a constant ω. This negative charge and the negative charge of the electron beam repel each other, and as a result, it becomes possible to suppress the radial divergence component of the electron beam, substantially reduce the beam spot diameter, and improve focus characteristics.

The resistive layer thus formed can suppress the spot shape of the electron beam and provide desired focus characteristics.

According to this embodiment, it is possible to improve the liquid-scum characteristics (of the electron beam) by forming a resistance layer on the conventional electron gun configuration electrode, and there is no need to change the design of the electron gun configuration. Therefore, it is possible to easily obtain a cathode ray tube with improved focus characteristics. Further, there is no need to use means for adding an auxiliary electrode as shown in Japanese Patent Publication No. 55-22906 to improve the focus characteristics.

Next, a second embodiment of the present invention will be described.

FIG. 3 is a front view of the fifth grid (G5) seen from the sixth grid (G6) side corresponding to FIG. 2.

In FIG. 3, (G5) is the fifth grid or resistance layer,
■ is through the side beam passage hole.

Here, a resistance layer 0 is formed in a semicircular arc shape in a portion far from the tube axis near the side beam passage hole opening in the same manner as in the first embodiment, and when a predetermined voltage is applied to each electrode, the resistance layer forming electrode An asymmetrical electrostatic lens as shown in FIG. 4 is formed between the grid and the adjacent sixth grid (G6). Fourth
The figure is a schematic diagram of the main part of FIG. 1 showing equipotential lines between the fifth grid (G5) and the sixth grid (G6).

The side beam is deflected toward the tube axis by the asymmetric electrostatic lens formed in this way.

As a means of deflecting the side beam toward the tube axis,
As shown in Japanese Patent No. 2-32714, there is a means for decentering the side beam passing holes of opposing electrodes to form the main lens, but it requires a sophisticated process to decenter only the side beam passing holes and assembling them with high precision. Requires management.

According to this embodiment, it is possible to improve the convergence characteristics of the electron beam by forming a resistive layer on the conventional electron gun #4, and there is no need to change the design.
Desired convergence characteristics can be obtained simply by changing the shape of the resistive layer. Further, when assembling the electron gun, the electron beam passage hole can be set with the simplest coaxial setting, so there is no need for complicated assembly jigs and process control.

Next, a third embodiment of the present invention will be described.

Figure 5 corresponds to Figure 3, and the 5th grid and others are the 3rd grid.
It is similar to the figure. Here, in the vicinity of the center beam passage hole, a resistance layer is formed in an annular manner in the same manner as in the first embodiment.
form. As shown in the diagram, near the side beam passage hole 1, a semi-ellipse is formed so as to surround the electron beam passage hole and increase the area in the direction away from the tube axis, as in the first embodiment. A resistive layer 0 is formed in the same manner as in the first embodiment.

According to this embodiment, the same effect as in the first embodiment can be obtained by 1q
At the same time, the side beams shown in the second embodiment can also be deflected. . In other words, the present invention can improve not only focus characteristics but also convergence characteristics at the same time.

Furthermore, the shape of the resistive layer (2) is not limited to the above embodiment, but can be selected depending on the electron gun to which it is applied, and the desired characteristics can be imparted to the electron gun, and there is no need to change the design of the electrode configuration. .

In this example, the resistance layer was formed on the second grid (G2) and the fifth grid (G5), but the resistance layer was formed on the second grid (G2).
The same effect can be obtained no matter which electrode is formed, without being limited to the fifth grid (G5). In addition, a lead borate glass with 5nOz was used as the resistance layer, but
It is not limited to this.

(Effects of the Invention) According to the present invention, by forming a resistance layer on the electron gun electrode of a cathode ray tube and selecting the shape of the resistance layer, convergence characteristics and focus characteristics can be improved without changing the design of the electrode configuration. can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an electron gun section showing a first embodiment of the present invention, FIG. 2 is a front view of an electrode of a main part constituting the electron gun of FIG. 1, and FIG. A front view of an electron gun electrode showing a second embodiment, FIG. 4 is a schematic diagram of a main part of an electron gun electrode for explaining an asymmetric electrostatic lens, and FIG. 5 shows a third embodiment of the present invention. Electron gun section (*Front view, Figure 6 is color receiver @
A schematic cross-sectional view of the tube, and FIG. 7 is a schematic diagram showing the electrode configuration of a conventional electron gun. (G2)...Second grid (G5)...Fifth grid (6)...Resistance layer ■...Side beam passage hole (8)...Center beam passage hole Agent Patent attorney Nori Chika Yudo Ken Norio Ogo No. 1 Figure fg2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Procedural correction power (spontaneous) ``06''V, 4. date of change

Claims (1)

[Scope of Claims] 1) In a cathode ray tube equipped with an electron gun having a plurality of electrodes each having at least a cathode and an electron beam passage hole, at least a portion of at least some of the plurality of electrodes is located near the electron beam passage hole. A cathode ray tube characterized in that a resistance layer is formed on the cathode ray tube. 2) The cathode ray tube according to claim 1, wherein the resistance layer is formed in an annular shape along the electron beam passage hole. 3) The electron beam of the electron gun is composed of a plurality of electron beams, and the resistive layer is formed in a portion far from the tube axis near the electron beam passage hole. cathode ray tube.