JPH03116638A - Color picture tube - Google Patents

Abstract

PURPOSE:To enhance focusing performance of a color picture tube by setting the magnetic intensity of each of the pairs of permanent magnets according to the space between a pair of vertical permanent magnets and a pair of horizontal permanent magnets in the direction of the tube axis. CONSTITUTION:A center beam G and a pair of side beams B, R are arranged in a position separate by predetermined distance from a pair of vertical permanent magnets 29a, 29b and a pair of horizontal permanent magnets 27a, 27b, so that the irregularity of ellipticity of the beam spot of the center beam G and the pair of side beams B, R can be corrected. The pair of side beams B, R are emitted with an inclination to an electron gun structure body 20 so that the side beams B, R concentrate on one point at the center of a phosphor screen 5. Thus the magnetetization intensity of each of the pairs of permanent magnets is set to proper strength according to the space between the pair of horizontal permanent magnets 27a, 27b in the direction of the tube axis. Therefore, the beam spot of three electron beams formed at the center of the phosphor screen can be corrected to almost a circle, which enhances focusing performance of a color picture tube.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a color picture tube and its deflection device that improves the deflection aberration caused by the deflection magnetic field of the deflection device and improves focus characteristics. Regarding.

(Prior Art) Generally, a color picture tube has an envelope (■) consisting of a panel and a funnel (■), as shown in FIG. A phosphor screen (2) consisting of a color phosphor layer is formed, and a shadow mask (2) is placed opposite to this phosphor screen (2). In addition, there are 3 electron beams (
B), (G).

An electron gun structure (■) that emits (R) is provided, and three electron beams (B) and (G) are emitted from this electron gun structure (■).

(R) is deflected horizontally and vertically by a deflection device (9) attached to the outside of the boundary between the cone portion (8) of the funnel ■ and the neck ■, and the phosphor screen ■ is deflected by the deflection device (9). As shown in FIG. 14, a pair of horizontal deflection coils (10) that deflect three electron beams in the horizontal direction;
It has a pair of vertical deflection coils (11) that deflect in the vertical direction.

In the color picture tube, in order to display a correct image on the phosphor screen (2), three electron beams (B), (G) are required to cover the entire surface of the phosphor screen (2).

It is necessary to concentrate (R) correctly. Therefore, in particular, the electron gun structure ■ is made up of a center beam (G) and a pair of side beams (B), (R), which are arranged in a row and consist of three electron beams (B), (G), (R).
), and by taking advantage of the characteristics of this inline electron gun structure and making the deflection magnetic field formed by the deflection device (9) a specific non-uniform magnetic field, the phosphor screen ( c) Three electron beams (
There is a self-convergence type in-line color picture tube that concentrates B), (G), and (R). The deflection magnetic field of this self-convergence type in-line color picture tube is, for example, - three electron beams (B), (G), arranged in a row passing on the same horizontal plane as in a fishing boat.
It is known that a color picture tube that emits (R) is composed of a pincushion-shaped horizontal deflection magnetic field and a barrel-shaped vertical deflection magnetic field. By creating such a magnetic field, three electron beams (B), (G), (R) arranged in a row passing on the same horizontal plane can be transferred to the phosphor screen (C).
You can concentrate on one point above.

However, even if the magnetic field is configured as described above, in-line color picture tubes still suffer from comatic aberration in which the convergence of the center beam (G) and the side beams (B) and (R) shifts at the periphery of the screen. .

In order to correct this coma aberration, a magnetic material that combines with the rear leakage magnetic field of the deflection device is arranged in the electron gun structure, as published in Japanese Patent Publication Nos. 51-26208 and 54-23208.
In addition, without using a magnetic material that couples with the rear leakage magnetic field of such a deflection device, a current synchronized with the deflection current flowing through the vertical deflection coil is applied to the electron gun assembly side of the deflection device. A model with an auxiliary coil that creates a strong pincushion-shaped magnetic field by flowing the current was developed in 1973.
It is disclosed in Japanese Patent No. 7-45748.

However, even if the color picture tube is constructed in this way, the spot of the electron beam on the phosphor screen will still be distorted according to its deflection. That is, as shown in FIG. 15, the spot (13) of the electron beam deflected by the uniform magnetic field becomes a nearly perfect circle over the entire surface of the screen (14). However, as shown in Figure 16, the spot (13) of the electron beam deflected by the non-uniform magnetic field is shaped like an oblong ellipse with its major axis in the horizontal axis direction at the horizontal axis (X-axis) end of the screen (14). distorted. That is, as shown in the 17th (A), the pincushion horizontal deflection magnetic field (15)
As a result, the upper half of each electron beam (B), (G), (R) is directed downward by the barrel-shaped vertical deflection magnetic field (16), as shown in Figure 17 (B) below, each electron beam CB),
The right halves of (G) and (R) receive the Lorentz force that presses them to the right and the left halves to the left, causing them to be distorted into oblong ellipses with their major axes in the horizontal axis direction. Especially a pair of side beams (B
), (R), the magnitude of the force received on the left and right sides of the beam is different, and the direction of the force received is opposite for the electron beam (B) on the left side of the screen and the electron beam (R) on the right side. Therefore, a pair of side beams (B
), (R) spots are shown in Figure 16 (13B),
As shown by (13R), they tilt in directions that intersect with each other. As a result, this horizontal or vertical deflection field (15), (1
6) Due to the deformation and inclination of the beam spot, one screen (
14) The focus characteristics in the peripheral area are extremely poor. Moreover,
The deterioration of the focusing characteristics is a major cause of hindering the improvement of the performance of the electron gun assembly.

Therefore, in order to improve the focus at the periphery of the screen (14), a compromise is made that emphasizes the uniformity of the focus at the center and the periphery of the screen (14) at the expense of the focus at the center of the screen (14). This has forced us to create a new design.

Furthermore, since the auxiliary coil disclosed in Japanese Utility Model Publication No. 57-45748 utilizes a current synchronized with the deflection current flowing through the vertical deflection coil, the problem described above occurs. In other words, when an electron beam is deflected in the vertical axis direction, the electron beam is excessively deflected in the vertical axis direction on the electron gun assembly side of the deflection device due to the magnetic field generated in the horizontal direction on the horizontal axis, causing the neck of the funnel to They tend to collide with the inner walls, creating so-called neck shadows on the screen where the electron beams do not reach (areas where no light is emitted).

In addition, since this auxiliary coil has a structure in which a coil is wound around a magnetic material and a current is passed through the coil, it becomes expensive as a correction element and is difficult to reduce in price.Furthermore, the deflection device varies depending on the receiver of each set manufacturer. They are often used with different impedances, and the current flowing through the deflection coils varies depending on the difference in impedance. therefore,
In order to make the effect of the auxiliary coil appropriate for such a deflection device, it is necessary to change the specifications of the auxiliary coil in accordance with the impedance of the deflection coil, which is not suitable for mass production.

(Problems to be Solved by the Invention) As described above, conventionally, the in-line electron gun structure has an in-line type electron gun structure that emits three electron beams arranged in a row passing on the same horizontal plane, and the three electron beams are deflected by a pincushion horizontal deflection magnetic field. and a deflection device that forms a barrel-shaped vertical deflection magnetic field.
There is a self-converging in-line color picture tube that concentrates the light onto a phosphor screen. However, in this color picture tube, coma aberration occurs in which the convergence of the center beam and a pair of side beams deviates at the periphery of the screen. In order to correct this coma aberration, conventional methods have been to place a magnetic material in the electron gun body that combines with the leakage magnetic field at the rear of the deflection device, or to provide an auxiliary current that is synchronized with the vertical deflection current to the electron gun body side of the deflection device. Some devices have coils arranged, but even with this configuration, the spot of the electron beam on the phosphor screen is a horizontally long ellipse with the long axis in the horizontal direction at the horizontal and vertical ends of one screen. In particular, at the end of the vertical axis, the spots of the pair of side beams are tilted in a direction that intersects with each other, significantly deteriorating the focusing characteristics at the periphery of the screen. This deterioration of the focus characteristics becomes a major factor that hinders the improvement of the performance of the electron gun assembly, and poses problems such as hindering improvement of the focus characteristics over the entire screen.

This invention was made to solve the above problem, and reduces the distortion of the electron beam spot, that is, the deflection aberration, caused by the deflection magnetic field of the deflection device, and thereby prevents the deterioration of focus characteristics at the periphery of the screen. It is an object of the present invention to provide a color picture tube and its deflection device that prevent the above problems and have good focus characteristics over the entire screen.

[Structure of the invention]

(Means for Solving the Problems) The present invention has an in-line electron gun structure that emits three electron beams arranged in a row, each consisting of a center beam and a pair of side beams, passing on the same plane. A first deflection coil that mainly forms a pincushion-shaped deflection magnetic field that deflects the emitted three electron beams in the direction in which they are arranged, and a mainly barrel-shaped deflection magnetic field that deflects the three electron beams in a direction perpendicular to the direction in which they are arranged. Second to do
In a color picture tube equipped with a deflection device having a deflection coil and its deflection device, on the path of the three electron beams between the deflection device and an electron lens part of an electron gun assembly that focuses the three electron beams onto a phosphor screen. , a pair of permanent magnets axially symmetrical with respect to the central axis of the deflection device and with opposite polarities in the same direction as the arrangement direction of the three electron beams and in a direction perpendicular to the arrangement direction of the child beams; A pair of permanent magnets in a direction perpendicular to the direction in which the electron beams are arranged are arranged at a predetermined distance from the pair of permanent magnets in the same direction as the direction in which the three electron beams are arranged, and a second deflection coil is formed. This is a color picture tube in which the strength and position of the magnetic field generated by each permanent magnet are set so as to generate a pincushion-shaped magnetic field that compensates for the deflection aberration caused by the deflection magnetic field.

(Function) As described above, a pincushion magnetic field is provided on the path of the three electron beams between the deflection device and the electron lens section of the electron gun assembly to compensate for the deflection aberration caused by the deflection magnetic field formed by the second deflection coil. a pair of permanent magnets are arranged in the same direction as the direction in which the three electron beams are arranged and in a direction perpendicular to the direction in which the three electron beams are arranged, respectively, with opposite polarities and axially symmetrical with respect to the central axis of the deflection device so as to generate the beam. When the pair of permanent magnets in the direction orthogonal to the arrangement direction of the three electron beams are placed at a predetermined distance from the pair of permanent magnets in the same direction as the arrangement direction of the three electron beams toward the electron gun assembly, the Opposite to the pincushion magnetic field formed by a pair of permanent magnets arranged in a direction perpendicular to the arrangement direction and the Lorentz force of the barrel-shaped deflection magnetic field of the second deflection coil that is exerted on a pair of side beams between the magnetic poles of adjacent permanent magnets. A magnetic field is formed that exerts a Lorentz force of In addition, it is possible to correct the non-uniformity of the spot shapes, that is, the ellipticities of the electron beams between the center beam and the pair of side beams at the center of the phosphor screen.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

Embodiment 1 FIG. 1 shows an embodiment of a self-convergence type in-line color picture tube. This color picture tube has an envelope ■ consisting of a panel ■ and a funnel ■. ■A phosphor screen (■) consisting of three-color phosphor layers that emit light in blue, green, and red is formed on the inner surface. In addition, an in-line electron gun assembly (20), which will be described later, is arranged in the neck 0 of the funnel ■, which emits three electron beams (B), (G), and (R) arranged in a line that pass on the same horizontal plane. . moreover.

Three electron beams (B), (G), (R) emitted from the electron gun structure (20) are applied to the outside of the boundary between the cone (8) of the funnel (2) and the neck 0 in horizontal and vertical directions. A deflection device (9) is installed to scan the phosphor screen 0 by deflecting the light.

The deflection device (2) generates three electron beams (B
), CG), and (R) are concentrated on the phosphor screen 0. As shown in Figure 2, it is wound in a saddle shape, and is placed vertically inside the separator (22). A pair of horizontal deflection coils (23) mounted symmetrically (in the Y-axis direction) (see Figure 1),
For example, it is wound around the core (24) and the separator (22
) and a pair of vertical deflection coils (25) mounted on the outside. A pair of horizontal deflection coils (23) of this deflection device (!g) mainly have a pincushion-shaped deflection magnetic field that deflects the three electron beams emitted from the electron gun assembly (2o) in the horizontal direction (X-axis direction). A pair of vertical deflection coils (25) mainly form a barrel-shaped deflection magnetic field that deflects the three electron beams in the vertical direction (Y-axis direction) perpendicular to the arrangement direction of the three electron beams. Note that the term "mainly pincushion-shaped deflection magnetic field" and "mainly barrel-type deflection magnetic field" as used herein means that they are collectively a pincushion-type deflection magnetic field and a barrel-type deflection magnetic field, respectively.

In the color picture tube of this example, as shown in FIG. 2, the deflection device (
A pair of permanent magnets (27a) in the left and right direction so that they are axially symmetrical with respect to the central axis (Z) of 9) and have opposite polarities, (
27b) are arranged. Furthermore, a pair of permanent magnets (29a) and (29b) in the vertical direction are placed at a position (28) that is spaced a predetermined distance from the left and right pair of permanent magnets (27a) and (27b) toward the electron gun assembly. Axis (Z
) are arranged axially symmetrically and with opposite polarities. This arrangement has the following effects.

That is, as shown in FIG. 3, a pair of permanent magnets (29a) and (29b) arranged in the vertical direction have a strong pincushion shape corresponding to the barrel-shaped deflection magnetic field (30) formed by the vertical deflection coil. A magnetic field f(31) is generated on the electron beam path and exerts a Lorentz force that distorts the electron beam spot into an elliptical shape with the long axis in the vertical direction, contrary to the Lorentz force that the electron beam receives from the barrel-shaped vertical deflection magnetic field. At the same time, the phenomenon in which the spots of the pair of side beams are tilted is corrected. On the other hand, a pair of vertical permanent magnets (29a),
A pair of permanent magnets (27a) and (27b) arranged in the left-right direction at a predetermined distance from (29b) toward the fluorescent screen side.
generates a pincushion-shaped magnetic field (33) in the same direction as the pincushion-shaped horizontal deflection magnetic field (32), as shown in FIG. At the same time, a pair of permanent magnets in the vertical and horizontal directions (
29a), (29b).

(27a) and (27b) are arranged so that their polarities are opposite, so as shown in FIG. A magnetic field (34) is generated between the magnetic poles (29a) and (29b) through a predetermined interval in the tube axis direction. This magnetic field (34) is generated by a pair of side beams (B), (R
) applies a Lorentz force opposite to the direction in which the spot is tilted by the barrel-shaped vertical deflection magnetic field to the pair of side beams, and the pair of side beams (B) due to the barrel-shaped deflection magnetic field,
The inclination of the spot at the vertical edge of the (R) phosphor screen is significantly corrected.

Here, a pair of permanent magnets (29a) in the vertical and horizontal directions are provided.
, (29b), (27a), and (27b) are all arranged on the same plane, each pair of permanent magnets (29a
), (29b), (27a), (27b) and the effects that the pincushion magnetic fields (31) and (33) have on the beam spot at the center of the phosphor screen will be described. That is, as shown in FIG. 6, a pair of vertical permanent magnets (29a).

The pincushion-shaped magnetic field (31) generated by (29b) applies Lorentz forces (36) and (37) to the beam, which distort the beam spot into an elliptical shape with the long axis in the vertical direction, as described above. As shown in , the pincushion magnetic field (33) generated by the left and right pair of permanent magnets (27a), (27b) causes the Lorentz force (38), (39) that distorts the beam spot into an elliptical shape with its long axis in the horizontal direction. ) is added. Therefore, a pair of vertical permanent magnets (29a)
.

(29b) and a pair of left and right permanent magnets (27a),
By setting the magnetization strength of (27b) to an appropriate strength, the beam spot of the three electron beams at the center of the phosphor screen can be made into a nearly perfect circle beam spot.

However, as shown in Figure 3, in an in-line electron gun structure in which a center beam and a pair of side beams are arranged in a line on the same plane, the center beam is located at the center of the tube axis, while the pair of side beams Since the center is off-axis from the tube axis center, two pincushion-shaped magnetic fields (31
), (33) The magnitude of the Lorentz force received by the center beam and the pair of side beams is different. As a result, as shown in Figure 8, each pair of permanent magnets in the vertical and horizontal directions (
29a), (29b), (27a), (27b)
When the magnetization strength is set, the beam spot of the center beam becomes an elliptical distorted beam spot with the long axis in the vertical direction. This vertical ellipticalization of the beam spot and the non-uniformity of the spot shape of the center beam and the pair of side beams, that is, the ellipticity, cause a deterioration of the tactility at the center of the phosphor screen, making the focus quality of the color picture tube undesirable. This will result in a loss.

However, as in this embodiment, a pair of vertical permanent magnets (2
9a) and (29b) as a pair of left and right permanent magnets (27
a) and (27b), by arranging the beam spot at a predetermined interval to correct the non-uniformity of the ellipticity of the beam spots of the center beam (G) and the pair of side beams (B) and (R). can do. That is, the electron beam is transmitted to the electron gun assembly (20) as shown in FIG.
After it is ejected, it diverges and hits the center of the fluorescent screen ■. Therefore, a pair of vertical permanent magnets (29a),
In the area where the pincushion magnetic field generated by (29b) acts, the electron beam diameter is still small, so the Lorentz force applied by the pincushion magnetic field to the electron beam is weak, and the beam spot of the center beam (G) in particular is aligned with the long axis in the vertical direction. It is possible to suppress distortion into a vertically oblong ellipse shape. In addition, as shown in FIG. 11, a pair of side beams (B),
(R) is emitted from the electron gun assembly (20) at an angle so that it is concentrated at one point at the center of the phosphor screen. In the region where the side beams act on the side beams, the pair of side beams (B) and (R) approach the center beam (G), that is, the tube axis (Z). Therefore, since the pair of side beams (B) and (R) pass through an area where the Lorentz force received from the pincushion magnetic field formed by the pair of left and right permanent magnets (27a) and (27b) is weak, the electron beam spot is horizontal. It is possible to suppress distortion into a horizontally oblong ellipse with the long axis in the direction.

Therefore, a pair of vertical permanent magnets (29a), (29
b), and a pair of left and right permanent magnets (27a), (27
By setting the magnetization strength of each pair of permanent magnets to an appropriate strength according to the distance in the tube axis direction made in b), the beam spot of the three electron beams at the center of the phosphor screen can be approximately adjusted as shown in Figure 9. It can be corrected to a perfect circle.

Example 2 In Example 1, a pair of permanent magnets (27a
), (27b) are arranged at the end of the electron gun structure side of the deflection device (9), but the present invention is not limited thereto. For example, as shown in FIG. (
24) may be placed in the vicinity of 〆/. In this case, there are pairs of permanent magnets (29a) in the vertical and horizontal directions.

(29b), (27a), and (27b) can be placed in a region where the electron beam is more divergent and has a larger beam diameter, that is, closer to the phosphor screen, which has the effect of correcting the distortion of the beam spot at the vertical end of the phosphor screen. is larger, which is even more desirable.

〔Effect of the invention〕

A pair of left and right deflectors are provided at the electron gun structure side end of a deflection device that forms a deflection magnetic field that deflects three electron beams arranged in a row passing through the same plane in the arrangement direction and a direction perpendicular to the arrangement direction, and one pair on the left and right at the electron gun structure side end. If a pair of upper and lower permanent magnets that generate a pincushion-shaped magnetic field are placed further toward the electron gun structure side at a predetermined interval, the pincushion-shaped magnetic field generated by these two pairs of permanent magnets will cause the vertical deflection coil to It corrects the distortion that the generated barrel-shaped magnetic field exerts on the electron beam spot to improve focusing performance at the end of the vertical axis of the phosphor screen, and also corrects the non-uniformity of the beam spots of the three electron beams at the center of the phosphor screen. Since the focus performance deterioration at the center of the phosphor screen can be improved, it is possible to provide a high-resolution, high-performance color picture tube with even better focus performance.

[Brief explanation of drawings]

1 to 11 are detailed explanations of the present invention, and FIG. 1 is a schematic cross-sectional view of a color picture tube according to a first embodiment;
Fig. 2 is a perspective view showing the deflection device attached to the color picture tube of Fig. 1 and two pairs of permanent magnets attached to this deflection device, and Fig. 3 is a pincushion type in which the two pairs of permanent magnets are generated. A diagram to explain the effect of a magnetic field on the electron beam spot. Figure 4 is a diagram to explain the pincushion magnetic field generated by a pair of left and right permanent magnets. Figure 5 is a diagram to explain the pincushion magnetic field generated by a pair of permanent magnets in the upper and lower and left and right directions A diagram to explain the pincushion-shaped magnetic field formed by the magnet. Figure 6 is a diagram to explain the effect that the pincushion-shaped magnetic field generated by a pair of upper and lower permanent magnets has on the electron beam spot. Figure 7 is a diagram to explain the effect on the electron beam spot. FIG. 8 is a diagram for explaining the effect of the pincushion magnetic field generated by a pair of permanent magnets on the electron beam spot, and is intended to supplement the explanation of FIG. 3, and is a diagram showing the shape of the electron beam spot. Fig. 9 is a diagram showing the electron beam spot shape for explaining the electron beam spot obtained by the action of the pincushion-shaped magnetic field generated by two pairs of permanent magnets according to the present invention, and Fig. 10 shows the electron beam diameter and the upper and lower pairs. FIG. 11 is a diagram for explaining the positional relationship between a pair of side beams and a pair of left and right permanent magnets, and FIG. 12 is a diagram for explaining the positional relationship between a pair of side beams and a pair of left and right permanent magnets. 13 is a schematic sectional view of a conventional color picture tube, FIG. 14 is a perspective view showing the configuration of a deflection device attached to the color picture tube of FIG. 13, and FIG. 15 is a schematic sectional view of a conventional color picture tube. FIG. 16 is an explanatory diagram of the shape of an electron beam spot deflected by a deflection device that generates a magnetic field. FIG. 16 is an explanatory diagram of the shape of an electron beam spot deflected by a deflection device that generates a non-uniform magnetic field. FIG. 17(B) is a diagram for explaining the influence of a pincushion-shaped horizontal deflection magnetic field and a barrel-shaped vertical deflection magnetic field on an electron beam, respectively. 5... Fluorescent screen, 9... Deflection device, 20...
. . . Electron gun structure, 24 . . 25 . . . Vertical deflection coil, 26 .
, 29b... A pair of vertical permanent magnets, 30... Barrel-shaped vertical deflection magnetic field; B, R... A pair of side beams, G... Center beam. A, Figure 1 Figure 2

Claims (1)

[Claims] An in-line electron beam forming unit that forms three electron beams consisting of a center beam and a pair of side beams, and an electron lens unit that focuses the three electron beams, and emits three electron beams arranged in a row that pass on the same plane. a gun assembly, a first deflection coil that mainly forms a pincushion-shaped deflection magnetic field that deflects the three electron beams in the direction in which they are arranged, and a mainly barrel-shaped deflection magnetic field that deflects the three electron beams in a direction perpendicular to the direction in which they are arranged. a deflection device including a second deflection coil, and a path of three electron beams between the deflection device and the electron lens portion of the electron gun assembly in accordance with the deflection magnetic fields formed by the first and second deflection coils. A pair of permanent magnets are arranged on the top, axially symmetrical with respect to the central axis of the deflection device, with opposite polarities, in the same direction as the three electron beam array direction, and in a direction perpendicular to the three electron beam array direction. , and a pair of permanent magnets perpendicular to the arrangement direction of the three electron beams are arranged at a predetermined interval toward the electron gun structure with respect to the permanent magnets in the same direction as the arrangement direction of the three electron beams, and the second deflection A color picture tube characterized in that the strength and position of the magnetic field generated by each permanent magnet are set so as to generate a pincushion-shaped magnetic field that compensates for deflection aberration due to the deflection magnetic field formed by the coil.