JPS6343245A - Electron gun - Google Patents

Abstract

PURPOSE:To improve a focusing property and to make quality control easy, by defining three electron beam passing apertures of a prescribed shape with a converging electrode and with each of plates confronting each other of an anode in an inline state. CONSTITUTION:Three apertures 9-11 are defined to a converging electrode 3 in an inline state in confrontation with an anode 4. The aperture 10 is formed at the center to an oval shape having a short axis (a) in an inline direction. Each of the aperture 9, 11 at the opposite sides has an outside edge portion formed to a shape surrounded by a straight line (d) orthogonal to a direction shown by an arrow A, two circular arcs (e) contiguous to the straight line and an oval arc (f). The apertures 9, 11 are longer in a longitudinal direction and has a longer axis (b) which is longer than the longer axis of the aperture 10. Further, apertures 12-14, which are the same as those of the converging electrode 3, are defined to a plates 22 of an anode 4, the plates 22 confronting the electrode 3. Since the apertures 9-13 of the electrode 3 and the anode 4 are defined in a longitudinally longer shape, they can be made larger in size without increasing distances between the respective apertures 9-14, whereby a focusing property can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an electron gun for a color cathode ray tube, and more particularly to an in-line type electron gun in which three beam passing holes through which the electron beam passes are arranged in a straight line. It is.

[Prior Art] Generally, the size of an image point on a fluorescent screen in a cathode ray tube, that is, the focusing performance, influences the sharpness of an image. For this reason, there are electron guns that improve focusing performance by increasing the effective diameter of the focusing lens to reduce the spherical aberration of the focusing lens (for example,
211743), which is shown in FIG.

In Fig. 3, in front of the three cathodes (5) arranged in line, there are a control electrode (1), an acceleration electrode (2),
A focusing electrode (3) and an anode (4) are arranged in this order. Small electron beam passage holes (6) and (7) through which the electron beam B passes are provided in-line in the control electrode (1) and the acceleration electrode (2), respectively. In addition, the control electrode (2) in the focusing electrode (3)
and an oval plate (20) facing the anode (4),
(21) and the oval plate (2) of the anode (4).
2) have three electron beam passing holes (hereinafter simply referred to as passing holes) (8), (9), (1
0), (11) and (12), (13).

(14) is provided inline. The focusing electrode (3) and anode (4) forming the focusing lens have an elliptical through hole (lo) (13) in the center as shown in FIG. On the other hand, the passage holes (9) on both sides, m
), (12), and (14) are the central passage holes (10) and (13) side parts (9a) and (ll
a) , (+2a).

(+4a) is a semi-ellipse, the outer part (9b).

(Ilb), (12b), and (14b) are formed in a semicircular shape. The above passage hole (8)...(14)
) is parallel to the inline array.

In the above conventional technology, the long axis is provided in the vertical direction, and the passage hole (9
)...By making (14) vertically long, the passage hole (9
)...The aperture area of (14) is increased to increase the effective diameter of the focusing lens. In addition, each passage hole (9)...
- By keeping the distance between (14) small, it is possible to prevent the condensation error from increasing at each point on the phosphor screen, or from deteriorating the withstand voltage characteristics due to the electron gun being close to the inner wall of the bulb neck. are doing.

[Problem to be solved by the invention] By the way, the center (10) of the center passage (10), (13)
0c), from (13c), through holes (9) on both sides
, (11).

(12), center for inspection in (14) (!
3c).

The distance S between the centers of (llc), (12c), and (14c) needs to be processed to a set value. For this reason, conventionally, the inspection jig is connected to each of the passage holes (6)...
- Each electron gun is inspected by inserting it into (14), and more precise sampling inspections are also conducted. In this sampling inspection, for example, a light source is installed in front of the anode (4), the shape of the anode (4) is enlarged on a screen, and the shape of the passage holes (12)...(14) is determined by the projected shadow. The position is measured. However, as mentioned above, the passage hole (12
)...If the (eye) is not circular, its center (12
c)...(14c) is not easy to determine, therefore,
Not only does the sampling inspection become complicated, but also the accuracy of the inspection decreases. In other words, 1. Quality control is not easy.

In addition, the focusing electrode (3) and anode (4) in Fig. 3 are connected to the passage holes (9), (11), (12) on both sides.
.

An assembly jig called a mandrel having a cross section slightly smaller than (14) is inserted through the poles (3) and (4) to assemble them. However, the passage holes on both sides (9
), (u), (12), and (14) are formed by continuous curves in the circumferential direction, so that the mandrel is rotatably fitted to the poles (3)' and (4). will be combined. Therefore, assembly accuracy is reduced, which causes a reduction in focus performance.

This invention has been made in view of the above-mentioned conventional problems, and aims to provide an electron gun with improved focusing performance and easy quality control.

[Means for Solving the Problems] In order to achieve the above object, the present invention first provides three electron beam passing holes provided in-line in each of the mutually opposing plates of the focusing electrode and the anode. The passage hole of at least one pole is formed in an elliptical shape with the central passage hole having a short axis in the inline direction. In addition, the passing hole of one pole has a straight line extending in a direction perpendicular to the inline direction at the outer edge of the passing hole, two arcs connected to both ends of this straight line, and two circular arcs connected to both ends of the straight line. It is connected to the two circular arcs on the side closer to the central passage hole than the straight line, and is surrounded by an elliptical arc having a long axis parallel to the straight line. The passage holes on both sides have longer lengths in the longitudinal direction than the central passage hole.

[Function] According to the present invention, the central passage hole has a short axis in the inline direction, and the passage holes on both sides have long axes parallel to a straight line extending in a direction perpendicular to the inline direction. Since the three passage holes are formed vertically, the area of each passage hole can be increased without increasing the distance between each passage hole. Since the passage holes on both sides have straight portions extending perpendicularly to the inline direction, the centers for inspection of the passage holes on both sides can be easily determined based on the straight portions. In addition, since the straight line connecting the two circular arcs forms a large discontinuity, the straight line of the passage hole on both sides and the straight line of the mandrel come into contact with each other, and the mandrel fits into the passage hole on both sides without rotating. Assembly accuracy is improved.

On the other hand, since straight portions are provided in both passage holes where electric field changes are larger than those in the central passage hole, electric field changes in the straight portions become even larger. In other words, the focal length becomes shorter. On the other hand, by making the length of the passage holes on both sides in the major axis direction longer than that of the center hole, the length of the straight line relative to the length of the circular arc of the passage holes on both sides can be shortened. Therefore, the linear length is sufficient for the inspection and assembly, and the electric field change can be made small, so that the focal length can be corrected. Therefore, the deviation in beam balance caused by providing the straight line is reduced.

[Example] Embodiments of this invention will be described below with reference to the drawings.

In Figure 1, there are two oblong plates (2G).

(21) and a cylindrical part (23), the focusing electrode (3) has three passage holes (9)...(11) in an oval plate (21) facing the anode (4) in Fig. 2. is provided inline. The central passage hole (10) among the passage holes (8)...(11) is formed in an elliptical shape with its minor axis a in the inline direction (direction of arrow A), as shown in Fig. 1. There is.

On the other hand, among the three passage holes (9)...(11), the passage holes (9) and (11) on both sides are
), (11), a straight line id extending in a direction perpendicular to the arrow A direction (arrow C direction), and this straight line d
It is formed in a shape surrounded by two circular arcs e and an elliptical arc f that are continuous at both ends. This elliptical arc f is connected to two circular arcs e on the central passage hole (lO) side of the straight line d, and has a long axis parallel to the straight line d.

That is, the passage holes (9) and (11) on both sides are formed vertically, and the length in the longitudinal direction is larger than the length in the longitudinal direction of the central passage hole (10).

5. Note that the oval plate (22) facing the focusing electrode (3) in the anode (4) in FIG.
) similar passage holes (12), (13), (14
), and other configurations of the electron gun are:
This is the same as the conventional example, and detailed explanation thereof will be omitted."In the above structure, the present invention has a structure in which the passage holes (9)...(14) of the focusing electrode (3) and the anode (4) are formed vertically. Therefore, the area of each passing hole (8)...(14) can be increased without increasing the distance between each passing hole (8)...(14).Therefore, the effective diameter of the focusing lens can be increased. focus performance is improved.

By the way, the passage holes (9) and (11) on both sides of Fig.
) is irregularly formed. Here, in the present invention, the passage holes (9) and (11) on both sides have straight portions (9d) and (lid) parallel to the long axis. For this reason,
By enlarging and projecting the oval plate (21) on the screen, the center for inspection can be easily and accurately determined from the shadows of the straight line parts (9d) and (lid), which serve as references. Therefore, each passage hole (9), (1
Since the distance between the centers for inspection in 0) and (11) can be easily and accurately measured, sampling inspection is easy;
In addition, since the accuracy of inspection is improved, quality control of the electron gun becomes easier.

In addition, the focusing electrode (3) and anode (4) in FIG. 2 are connected to the mandrel (
30) and (31).

These mandrels (30), (31) have passage holes (9), (11), (12), (
14), and has a cross section corresponding to the above two poles (3),
(4) is fitted. Here, this invention
Two circular arc parts (9e), (lie).

Straight line section (9d) connected to (12e) and (14e)
, (tta).

(12d) and (14d) form a large discontinuity, so the passage holes on both sides (9), (11),
(12), (14) straight line part (9d), (lid
), (12d), (14d) and the straight part (31a) of the mandrel (31), (30), (
30a) come into contact with the passage holes (9) on both sides.
(11), (12), (14) are mandrel (
31) and (30) are fitted together so as not to rotate.

Therefore, the accuracy of assembling the poles (3) and (4) is improved, and the focusing performance is improved.

By the way, the passage holes (9) and (II
) has a large electric field change compared to the central passage hole (lO),
Furthermore, since the straight portions (9d) and (hd) are provided, the electric field change in the portion where the straight portions (9d) and (lid) are provided becomes even larger. In other words, the fishing distance in this area becomes shorter and the beam balance is disrupted.

On the other hand, the present invention provides passage holes (9) on both sides,
(11) is longer in the direction of arrow C than the central passage hole (10), so the passage holes (9) on both sides have a large electric field change.
, (11) are corrected to a small value, and the linear portion (9
d).

Since the length of (lid) can be made small, the straight portions (9d) and (lid) are provided with sufficient length for the above inspection and assembly, and the electric field change due to the straight portions (9d) and (lid) is minimized. It is possible. Therefore, the fish collection distance is corrected, and the beam balance can be reduced.

In addition, the three passage holes (9)...(11) or (1) of either the focusing electrode (3) or the anode (0) in FIG.
2)...(14) may be a circular hole.

[Effects of the Invention] As described above, according to the present invention, since straight portions are provided in the passage holes on both sides, the focusing performance of the electron gun is improved and quality control becomes easy. Further, the distortion of the beam balance due to the provision of the straight portion can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a focusing electrode showing an embodiment of the present invention;
FIG. 2 is an exploded perspective view showing the general structure of an electron gun, FIG. 3 is an exploded perspective view showing the general structure of a conventional electron gun, and FIG. 4 is a longitudinal sectional view of an anode and a focusing electrode. (1)...control electrode, (2)...acceleration electrode, (3)
... Focusing electrode, (4) ... Anode, (5) ... Cathode, (9), (11). (12), (14)... Passing holes on both sides, (10
), (13)...Central passage hole, (21),
(22)...Plate, a...short axis, b...long axis. d...straight line, e...circular arc, f...elliptical arc. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) In front of three cathodes arranged in-line,
The electron gun is provided with at least a control electrode, an accelerating electrode, a focusing electrode, and an anode, and at least three electron beam passing holes are provided in-line in each of the mutually opposing plates of the focusing electrode and the anode. The passage hole of one pole is formed into an elliptical shape with the central passage hole having a short axis in the inline direction, and the passage holes on both sides extend in a direction perpendicular to the inline direction at the outer edge of the passage hole. A straight line, two circular arcs connected to both ends of this straight line, and connected to the two circular arcs on the central passage hole side of the straight line,
The electron gun is formed in a shape surrounded by an elliptical arc having a major axis parallel to the straight line, and the length of the passage holes on both sides in the major axis direction is larger than the length of the central passage hole in the major axis direction.