JP2002008558A - Electron gun for color cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy in assembling of electrode forming a main lens, and to form a good beam spot on a luminous surface of a color cathode ray tube, and to reproduce a picture with higher resolution. SOLUTION: For the color cathode ray tube electron gun with a main lens formed between a focusing electrode 40b and an anode 50a, at least either the focusing electrode 40b or the anode 50a is a platy electrode with unevenness, and connected to a cylinder-shaped shield electrode 40c or 50b as another member, at the side opposing to the side where another electrode of pairing locates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for a color cathode ray tube used for a television, a computer display, and the like, and more particularly to a method for assembling an in-line electron gun.

[0002]

2. Description of the Related Art In general, a color cathode ray tube has an electron gun disposed inside a vacuum envelope made of glass, corresponds to three colors of red, green and blue, and has a luminance signal of an image receiving circuit. The three electron beams to be modulated are generated. As this electron gun, a so-called in-line electron gun in which three electron beams are arranged in a horizontal line is frequently used.

There are various types of in-line type electron guns depending on the application.
As shown in FIG. 1, the one including the cathodes 10a, 10b, 10c, the control electrode 20, the acceleration electrode 30, the first focusing electrode 40a, the second focusing electrode 40b, and the anode 50 is the most basic one. Among these electrodes, the control electrode 20, the focusing electrodes 40a and 40b, and the anode 50 have a cup shape.

There are two types of methods for manufacturing these electrodes. One is a method called “transfer press”, which is used for manufacturing a cup-shaped electrode such as the focusing electrode 40. This method is a method in which a circular small metal piece called a surface patch is cut out from a hoop material (rolled metal sheet) and formed by drawing and pressing. In this method, although deep drawing can be performed, there is a disadvantage in that processing takes time. Another method is a method called “progressive pressing” and is used for manufacturing a plate-like electrode such as the accelerating electrode 30. In this method, a hoop material is sequentially processed, and parts are cut one by one in a final step of pressing. Although this method cannot perform deep drawing,
An advantage is that many parts can be manufactured per unit time.

[0005]

The molding by the transfer press has disadvantages in the production of the electrode parts as described below, as compared with the molding by the progressive press. That is, in the case of molding by transfer press, first, a hoop material of a metal material is cut off to form a material patch, which is sequentially processed with a punch and a die to increase the cup-shaped depth. Since the stroke between the punch and the die is larger than that of the progressive press, the number of shots per unit time is reduced, and the productivity is low. in addition,
As the pressing is performed, the metal material undergoes work hardening, and it becomes difficult to maintain the accuracy of the electrode shape, and the material may be broken.

In the electron gun structure shown in FIG.
If the component accuracy of the anode 50 and the component accuracy of the anode 50 fluctuate, the image reproduced by the cathode ray tube will be deteriorated as described below. Between the second focusing electrode 40b and the anode 50, as shown in the electron lens model of FIG.
0 is formed. The electron beam 70 emitted from the equivalent electron source 65 is focused by the main lens 60, and a beam spot 80 is formed on the fluorescent screen 75 of the color cathode ray tube. At this time, the cup-shaped second focusing electrode 4 as in the related art is used.
In the configuration using the anode 0b and the anode 50, poor accuracy occurs near the electron beam passing holes 5a, 5b, 5c, and 6a, 6b, 6c provided to the respective electrodes, and the beam spot 80 shown in FIG. So-called haze 85
And the image is degraded.

An object of the present invention is to improve the productivity and accuracy of electrode parts used in an electron gun, and to realize an in-line electron gun that realizes a good color image on a fluorescent screen of a cathode ray tube.

[0008]

According to the present invention, a focusing electrode and an anode are provided adjacent to each other in pairs, and a main lens is formed between the focusing electrode and the anode. In the electron gun for a color cathode ray tube to be performed, at least one of the focusing electrode and the anode is a substantially plate-shaped electrode having irregularities, and is a separate member on a side opposite to a side of the other paired electrode. It is connected to a shield electrode of a shape (claim 1).

According to this configuration, the assembling accuracy of the portion where the second focusing electrode on which the main lens is formed and the anode face each other is improved.

[0010] The substantially plate-shaped electrode is formed with the irregularities by drawing.

According to this configuration, since the conventional deep drawing is not used, work hardening of the material and breakage of the material can be prevented. In addition, the number of shots per unit time can be increased as compared with deep drawing, and the productivity of drawing can be increased.

A gap is provided between the substantially plate-shaped electrode and the shielding electrode, and the substantially plate-shaped electrode and the shielding electrode are electrically connected by a conductive member. 3).

According to this configuration, the connection between the substantially plate-shaped electrode and the shielding electrode can be easily performed.

Further, the focusing electrode is the substantially plate-shaped electrode, the focusing electrode and the shielding electrode are connected by the conducting member, and further, an end of the shielding electrode on a side opposite to the focusing electrode. A focusing electrode different from the focusing electrode is provided, a gap is provided between the another focusing electrode and the shielding electrode, and the conducting member electrically connects the another focusing electrode and the shielding electrode. (Claim 4).

According to this configuration, the assembling accuracy of the first focusing electrode can be improved.

[0016]

FIG. 1 is a sectional view of an in-line surface of an electron gun for a color cathode ray tube according to the present invention. As shown in FIG. 1, a cup-shaped control electrode 20 containing cathodes 10a, 10b, and 10c, a plate-shaped acceleration electrode 30,
The focusing electrode assembly 40 and the anode assembly 50 are sequentially arranged, and a main lens (not shown) is formed between the focusing electrode assembly 40 and the anode assembly 50.

The focusing electrode assembly 40 includes a first focusing electrode (another focusing electrode) 4 facing the acceleration electrode 30.
0a and a second focusing electrode (“focusing electrode” in the claims) 40b facing the anode structure 50, and these have gaps 12a and 12b between the cylindrical shielding electrode 40c, respectively. Conducting members 14a and 14b made of metal pieces, 1
They are electrically connected by 4c and 14d. The anode assembly 50 includes an anode 50a facing the second focusing electrode 40b, and a cylindrical shielding electrode 50b. Anode 5
Oa and the shield electrode 50b are electrically connected to each other by conductive members 16a and 16b made of metal pieces with the gap 15 interposed therebetween.

The first focusing electrode 40a is a plate-like electrode having three electron beam passage holes 19a, 19b, 19c.

The second focusing electrode 40b has three electron beam passage holes 17a, 1a and 1b through which three electron beams respectively pass.
7b and 17c, and each of the electron beam passage holes has a cylindrical portion protruding in a direction to recede with respect to the pair of anodes 50a. In addition, the peripheral portion of the second focusing electrode 40b also has a flat portion extending in a direction of receding with respect to the anode 50a and parallel to the tube axis, and these have irregularities. These irregularities are formed by drawing. In addition,
Although the drawings show the concavities and convexities in an enlarged manner, the actual second focusing electrode 40b has a plate thickness of about 0.2 to 0.5 [mm] and a maximum thickness (from the anode 50a side end face to the shielding electrode 40c side end face). Is about 2 [mm], and is a substantially flat plate having fine irregularities in appearance. The maximum thickness is 1-2 times the length of the tubular part.

The anode 50a has the same shape as the second focusing electrode 40b. It has three electron beam passage holes 18a, 18b, 18c through which the three electron beams respectively pass, and each of the electron beam passage holes moves in a direction to recede with respect to the pair of second focusing electrodes 40b. It has a protruding cylindrical portion. Further, the peripheral portion of the anode 50a is also the second focusing electrode 40b.
And a flat portion extending in a direction of receding with respect to the tube axis and parallel to the tube axis, and these form irregularities. These irregularities are formed by drawing.

The gaps 12a, 12b, between the first focusing electrode 40a and the shielding electrode 40c, between the shielding electrode 40c and the second focusing electrode 40b, and between the substantially plate-shaped electrode 50a and the shielding electrode 50b, respectively. The size of 15 is determined so that the influence of the electric field outside the electron gun does not reach the inside of the electron gun, and is selected from a value in a range of approximately 0.1 [mm] to 1.0 [mm].

As the conductive members 14a, 14c, 16a, etc., a metal ribbon made of the same material as the electrodes is used. The number and mounting position are arbitrary.

FIG. 2 shows a control electrode 20, an acceleration electrode 30, a first focusing electrode 40a, a second focusing electrode 40b, and a shielding electrode 40.
c shows a front view of the anode 50a and the shielding electrode 50b. Each electron beam passage hole is not limited to a perfect circle.

Next, a brief description will be given of a manufacturing process of the electron gun of the present invention.

First, a focusing electrode and an anode, at least one of which is a substantially plate-like electrode, at least one shielding electrode, a control electrode, an acceleration electrode, and the like are arranged in a predetermined order and position. Next, each electrode is fixed to a glass rod. Thereafter, the substantially plate-shaped electrode and the shield electrode are connected by a conductive member. As described above, by fixing the electrodes forming the main lens to the glass rod while keeping the positional relationship accurately, and then electrically connecting the electrodes, the assembling accuracy can be improved.

In the above embodiment, the focus electrode structure 40 is divided into three parts and the anode structure 50 is divided into two parts. However, at least one of the second focus electrode 40b and the anode 50a constituting the main lens or Both are preferably substantially plate-shaped electrodes.

Although the inline type electron gun has been described as an example, the present invention can be applied to a delta type electron gun.

[0028]

As described above, according to the present invention,
The accuracy of assembling the electrodes forming the main lens can be improved, a good beam spot can be formed on the phosphor screen of the color cathode ray tube, and an image with higher resolution can be reproduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electron gun for a cathode ray tube according to the present invention.

FIG. 2 is a front view of each electrode.

FIG. 3 is a sectional view of a conventional electron gun for a cathode ray tube.

FIG. 4 is a diagram illustrating an electron lens model.

[Explanation of symbols]

12a, 12b, 15 Air gaps 14a, 14b, 14c, 14d, 16a, 16b Metal pieces 17a, 17b, 17c, 18a, 18b, 18c, 1
9a, 19b, 19c Electron beam passage hole 40 Focusing electrode structure 40a First focusing electrode 40b Second focusing electrode 40c Shielding electrode 50 Anode assembly 50a Anode 50b Shielding electrode

Claims (4)

[Claims] 1. An electron gun for a color cathode ray tube, wherein a focusing electrode and an anode are provided adjacently as a pair and a main lens is formed between the focusing electrode and the anode, wherein the focusing electrode and the anode are provided. Is a substantially plate-shaped electrode having irregularities, and is connected to a cylindrical shielding electrode, which is another member, on a side opposite to a side of the other electrode that forms a pair. Electron gun for cathode ray tube. 2. An electron gun for a color cathode ray tube according to claim 1, wherein said substantially plate-shaped electrode has said irregularities formed by drawing. 3. A gap is provided between the substantially plate-shaped electrode and the shielding electrode, and the substantially plate-shaped electrode and the shielding electrode are electrically connected by a conductive member. 2. The electron gun for a color cathode ray tube according to 1. 4. The focusing electrode is the substantially plate-shaped electrode, the focusing electrode and the shielding electrode are connected by the conductive member, and further, an end of the shielding electrode on a side opposite to the focusing electrode. A focusing electrode different from the focusing electrode is provided, a gap is provided between the another focusing electrode and the shielding electrode, and the conducting member electrically connects the another focusing electrode and the shielding electrode. 4. The connection of claim 3,
3. The electron gun for a color cathode ray tube according to claim 1.