JPH11185655A - Color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To structure a color picture tube with high resolution and reliability, by making a beam spot small throughout a picture screen without decreasing brightness. SOLUTION: In a picture tube equipped with an electron gun 16 which has a triode part GE consisting of plural electrodes G1-G5 including a cathode K and first and second electrodes G1, G2 arranged in order adjacent to the cathode in a direction for a target 12 and a main lens part ML formed by plural electrodes to focus electron beams generated in the triode part on the target, the triode part GE is structured so that plural fine apertures 21a, 21b in the second electrode G2 to one aperture 20G of the first electrode G1, an electron beams divided into plural pieces are generated from the fine apertures of the second electrode G2 and the electron beams are centered by focusing and integrating the electron beams on the target by the main lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color picture tube, and more particularly to a color picture tube having a high resolution.

[0002]

2. Description of the Related Art Generally, a color picture tube has an envelope composed of a panel and a funnel, and an inner surface of the panel has
Stripe or dot 3 emitting blue, green and red
A phosphor screen (target) made of a color phosphor layer is provided, and a shadow mask having a large number of apertures formed therein is arranged opposite to the phosphor screen. On the other hand, an electron gun that emits three electron beams is arranged in the neck of the funnel. Then, the three electron beams emitted from the electron gun are deflected by the horizontal and vertical deflection magnetic fields generated by the deflection yoke mounted outside the funnel, and the phosphor screen is horizontally and vertically scanned through a shadow mask. , And a structure for displaying a color image. The electron gun generally has a triode section for generating an electron beam composed of three cathodes and first and second electrodes arranged adjacent to the cathodes in the direction of the phosphor screen, and an electron generated by the triode section. A main lens portion formed by a plurality of electrodes for focusing the beam on the phosphor screen.

In such a color picture tube, in particular, the electron gun is an in-line type electron gun which emits three electron beams arranged in a line composed of a center beam and a pair of side beams passing on the same horizontal plane, and emitted from the electron gun. A self-convergence type in-line color picture tube, in which the horizontal deflection magnetic field of a deflection yoke that deflects three electron beams arranged in a single row is pin-cushion type and the vertical deflection magnetic field is a barrel type, and is concentrated without using a special concentrator. Has been

In such a color picture tube, it is necessary to appropriately focus and concentrate three electron beams emitted from an electron gun in order to improve image characteristics drawn on a phosphor screen. It is.

Regarding the concentration of the three electron beams, a method of emitting the three electron beams emitted from the electron gun at an inclined angle in advance and a method of three electron beam passage holes of the electrode forming the main lens portion are described. There is a method of concentrating a pair of side beam passage holes by decentering them slightly outside the side beam passage holes of the adjacent electrode on the triode side. Both have been widely put to practical use.

On the other hand, the three electron beams are focused by an asymmetric magnetic field having a horizontal deflection magnetic field of a pincushion type and a vertical deflection magnetic field of a barrel type, as in the self-convergence type in-line type color picture tube. The self-concentrating method suffers from astigmatism. That is,
Regarding the pincushion-type horizontal deflection magnetic field, as shown in FIG. 8A, the electron beam 1 receives forces in the directions of arrows 3H and 3V by the pincushion-type horizontal deflection magnetic field 2H, and as shown in FIG. Beam spot 4 on the periphery of the screen
Are significantly distorted due to deflection aberration. This deflection aberration occurs because the electron beam is over-focused in the vertical direction, and a large halo 5 occurs in the vertical direction.
Therefore, due to the deflection aberration received by the electron beam, the resolution is significantly deteriorated in the peripheral portion of the screen.

Japanese Patent Application Laid-Open No. 61-9924 discloses an electron gun which solves the deterioration of resolution at the periphery of the screen due to the deflection aberration.
No. 9 (U.S. Pat. No. 4,814,670) states that
As shown in FIG. 9, a cathode K, first to fifth electrodes G1 to G5 arranged adjacent to the cathode K in the direction of the phosphor screen, and a deflection yoke is generated at the fourth electrode G4. 1 shows a dynamic focus type electron gun that applies a dynamic voltage that changes in synchronization with a magnetic field.

In this electron gun, the triode portion GE, the third electrode GE and the third electrode G1 to G3 are connected by the cathode K and the first to third electrodes G1 to G3.
The fourth electrode G3 and G4 form a quadrupole lens QL, and the fourth and fifth electrodes G4 and G5 form a main lens ML. As shown in FIG. 10 (a), the quadrupole lens QL has three vertically long non-circular electron beam passage holes 7a, 7b, 7c in the third electrode G3, as shown in FIG.
Four horizontally elongated non-circular electron beam passage holes 8 are formed in the fourth electrode G4.
a, 8b and 8c.

The correction of the deflection aberration in the electron gun is performed as follows. That is, when the electron beam lands on the center of the screen without being deflected, the quadrupole lens QL is not formed, and the electron beam is appropriately focused on the center of the screen by the main lens ML. On the other hand, when the electron beam is deflected in the peripheral direction of the screen, 4
A pole lens QL is formed, and the quadrupole lens QL diverges the electron beam in the horizontal direction and focuses the electron beam in the vertical direction. At this time, the convergence of the main lens ML in both the horizontal and vertical directions is weakened. Therefore, the electron beam is insufficiently focused in the vertical direction, but is focused by a focusing action due to deflection aberration (astigmatism). On the other hand, in the horizontal direction, the overall focusing in the horizontal direction hardly changes due to a decrease in the focusing action of the quadrupole lens QL and the focusing action of the main lens ML, and is insufficiently focused due to the magnetic field generated by the deflection yoke. . However, the periphery of the screen where this electron beam lands is farther away from the electron gun than the center,
It is also focused in the horizontal direction.

However, in such a dynamic focus type electron gun, especially in the case of a large tube, it is necessary to increase the vertical divergence of the quadrupole lens QL required for correcting the deflection aberration. Lens QL
Has a greater horizontal focusing effect. Therefore, it is necessary to greatly reduce the focusing effect of the main lens ML.
As a result, the potential difference between the electrodes required to reduce the focusing action of the main lens ML increases, which causes an increase in the circuit load of the television set, and a problem in safety such as discharge and withstand voltage, reliability, and the like. Also, with this dynamic focus type electron gun, the deflection angle of the electron beam deflected to the periphery of the screen differs between the horizontal direction and the vertical direction.
The beam spot at the periphery of the screen has a horizontally long elliptical shape that is long in the horizontal direction, and the resolution at the periphery of the screen is significantly deteriorated. In addition, there is a problem that moire occurs due to interference with the arrangement pitch of the electron beam passage holes of the shadow mask, leading to deterioration of image quality.

As an electron gun for solving the above problem, Japanese Patent Laid-Open Publication No. 3-95835 discloses a second quadrupole lens between a cathode of the electron gun and a quadrupole lens (first quadrupole lens). Is added to the first quadrupole lens, which is located closer to the phosphor screen than the second quadrupole lens, so that the first quadrupole lens has a function opposite to the convergence and divergence functions. An electron gun is shown in which the convergence angle in the vertical direction is reduced and the imaging magnification in the horizontal and vertical directions is substantially equal.

However, in such a configuration, the divergence angle of the electron beam becomes large at the time of a large current, as described in Technical Report of the Institute of Television Engineers of Japan (IDY92-17). When the divergence is caused, there is a principle problem that the horizontal beam spot diameter on the screen does not decrease due to the influence of the horizontal spherical aberration of the main lens.

As described above, the problem of the beam spot diameter on the screen cannot be solved only by taking measures in the main lens portion. In order to solve the problem of the beam spot diameter, it is fundamentally necessary to reduce the diameter of the electron beam emitted from the electron gun. However, if the diameter of the electron beam emitted from the electron gun is reduced in this way, the brightness on the phosphor screen is reduced, so that it cannot be simply implemented.

In order to solve the above problem, Japanese Patent Application Laid-Open No. 5-34
Japanese Patent Publication No. 3002 discloses that an electron beam passage hole of a first electrode adjacent to a cathode is constituted by at least four openings which are arranged rotationally symmetrically with respect to one cathode, so that one cathode receives one electron beam. An electron gun is shown in which an electron beam is formed into a plurality of fine electron beams, and the plurality of fine electron beams are focused on a phosphor screen by a main lens unit, thereby reducing a beam spot diameter without lowering screen brightness. ing.

However, in this configuration of the electron gun, since the potential difference between the first electrode forming a plurality of fine electron beams and the adjacent second electrode is small, the strength of the electron lens formed between these electrodes is weak. In addition, the electron beam cannot be appropriately focused, and as a result, a sufficient effect of reducing the beam spot diameter on the phosphor screen cannot be obtained.

[0016]

As described above, a self-convergence type in-line type color picture tube which deflects three electron beams arranged in a row from an electron gun by a non-uniform magnetic field generated by a deflection yoke is provided with a non-uniform type. Due to the astigmatism caused by the uniform magnetic field, the beam spot at the periphery of the screen is distorted, and the resolution at the periphery of the screen is significantly deteriorated.

As a means for solving the deterioration of the resolution due to the deflection aberration, a dynamic focus type electron gun for forming a triode portion, a quadrupole lens and a main lens along the traveling direction of the electron beam from the cathode to the phosphor screen. There is. However, in this electron gun, it is necessary to increase the vertical diverging action of the quadrupole lens as the size of the tube increases, and accordingly the horizontal focusing action of the quadrupole lens increases. For this reason, the potential difference between the electrodes forming the main lens becomes large, which causes an increase in the circuit load of the television set, and causes problems in safety such as discharge and withstand voltage, reliability, and the like. Further, in this dynamic focus type electron gun, the beam spot at the periphery of the screen has a horizontally long elliptical shape which is long in the horizontal direction, causing a problem that the resolution of the periphery of the screen is deteriorated, and the image quality is deteriorated due to the occurrence of moire. .

As an electron gun for solving such a problem,
Between the cathode of the electron gun and the quadrupole lens, a second 4
An electron gun has been proposed in which a polar lens is added and the first quadrupole lens located closer to the phosphor screen than the second quadrupole lens has functions opposite to the focusing and diverging functions. However, in the electron gun having such a configuration, a problem has been pointed out that the beam spot diameter in the horizontal direction on the screen is not reduced in principle.

In order to fundamentally solve the above problems, it is necessary to fundamentally reduce the diameter of the electron beam emitted from the electron gun. If the diameter of the electron beam itself is reduced, the brightness on the phosphor screen decreases, so that it cannot be simply implemented.

Therefore, the electron beam passage hole of the first electrode adjacent to the cathode is constituted by at least four holes arranged rotationally symmetrically with respect to one cathode, and the electron beam from one cathode is formed. An electron gun has been proposed in which a beam is formed into a plurality of fine electron beams, and the plurality of fine electron beams are focused on a phosphor screen by a main lens unit, thereby reducing a beam spot diameter without lowering screen brightness. I have. However, in this configuration, since the potential difference between the first electrode forming a plurality of fine electron beams and the adjacent second electrode is small, the electron beam cannot be properly focused, and as a result, the There is a problem that a sufficient effect of reducing the beam spot diameter cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an object to provide a color picture tube having high resolution and high reliability by reducing a beam spot over the entire screen without lowering the luminance. With the goal.

[0022]

According to the present invention, there is provided a cathode and a first cathode disposed in the direction of a target adjacent to the cathode.
A color picture tube including an electron gun having a triode portion including a plurality of electrodes including a second electrode, and a main lens portion formed by a plurality of electrodes for focusing an electron beam generated by the triode portion on a target. In the method, the triode portion is provided with a plurality of fine holes in the second electrode with respect to one hole in the first electrode, and a plurality of electron beams are generated by the fine holes in the second electrode. ,
The plurality of electron beams were formed so as to be converged, combined and concentrated on the target by the main lens unit.

Further, a plurality of fine openings of the second electrode are formed rotationally symmetric with respect to a center axis passing through the center of the opening of the first electrode.

Further, a plurality of fine openings of the second electrode were formed in the same size.

Further, the total area of the plurality of fine openings of the second electrode was made substantially equal to the opening area of the first electrode.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a color picture tube which is one embodiment of the present invention. This color picture tube has a panel 10 and an envelope composed of a funnel 11 integrally joined to the panel 10, and a stripe-shaped three-color fluorescent light emitting blue, green and red is formed on the inner surface of the panel 10. A phosphor screen 12 (target) composed of a body layer is provided, and a shadow mask 13 having a large number of apertures is arranged inside the phosphor screen 12 at a predetermined distance from the phosphor screen 12. On the other hand, an electron gun 16 for emitting three electron beams 15B, 15G and 15R arranged in a row composed of a center beam 15G and a pair of side beams 15B and 15R passing on the same horizontal plane is arranged in the neck 14 of the funnel 11. I have. The three electron beams 15B, 15G, and 15R emitted from the electron gun 16 are applied to the funnel 11
Is deflected by horizontal and vertical deflection magnetic fields generated by a deflection yoke 18 mounted on the outer side of the screen and horizontally and vertically scans the phosphor screen 12 through the shadow mask 13 to form a structure for displaying a color image. ing.

The electron gun 16 has a BPF (Bi-Potential).
Focus) type electron gun, as shown in FIG. 1, three cathodes K (1) arranged in a row in the horizontal direction (H-axis direction).
, Three heaters H (only one is shown) for heating each of the cathodes K, and first to fifth electrodes G1 to G1 to G5 which are sequentially arranged at predetermined intervals from the cathode K in the direction of the phosphor screen. G5.

The first to third electrodes G1 to G3 are a plate-like electrode having an integral structure having a major axis in the horizontal direction, and a fourth electrode G4.
Is a cylindrical electrode of an integral structure having a major axis in the horizontal direction, and the fifth electrode G5 is a cup-shaped electrode of an integral structure having a major axis in the horizontal direction.

On the plate surface of the first electrode G1, three circular electron beam passage holes 20B, 20G, 20R are provided horizontally corresponding to the three cathodes K as shown in FIG. They are formed in a line in the direction. On the other hand, on the plate surface of the second electrode G2, two fine circular openings 21a, 2a corresponding to the three cathodes K as shown in FIG.
1b is a set of three electron beam passage holes 22B, 22
G and 22R are formed in one row in the horizontal direction. The pair of apertures 21a and 21b are formed to be rotationally symmetric about an axis passing through the center of each electron beam passage hole of the first electrode. In the illustrated example, each electron beam passage hole of the first electrode is shown. Are formed symmetrically in the horizontal direction with respect to an axis passing through the center. The openings 21a and 21b are formed to have the same size, and the sum of the areas of the openings 21a and 21b is equal to the size of the electron beam passage hole of the second electrode of the conventional electron gun. It is formed so as to have almost the same area as the electron beam passage hole of one electrode G1. On the plate surface of the third electrode G3, three circular electron beam passage holes larger than the electron beam passage holes of the first electrode G1 are formed in a row in the horizontal direction, corresponding to the three cathodes. . On the surface of the fourth electrode G4 facing the third electrode G3, three circular electron beam passage holes larger than the electron beam passage holes of the third electrode G3 are formed in a row in the horizontal direction. The surface of the fourth electrode G4 facing the fifth electrode G5 and the surface of the fifth electrode G5 facing the fourth electrode G4 are formed by the electron beam passage holes in the surface of the fourth electrode G4 facing the third electrode G3. Also, three larger circular electron beam passage holes are formed in a row in the horizontal direction.

In the electron gun 16, the fifth electrode G5
An anode voltage of 25 to 35 kV supplied to an anode terminal 24 (shown in FIG. 3) provided on the funnel 11 is applied via a conductive film 25 (shown in FIG. 3) provided on the inner surface of the funnel 11 and the like. Is done. The fourth electrode G4 has a focus voltage of about 20 to 35% of the anode voltage, and the third electrode G3 has a focus voltage of 50 to 9% of the voltage applied to the fourth electrode G4.
A voltage of about 0% is further applied to the second electrode G2,
A cut-off voltage of about 1000 V, the first electrode G1 is kept at the ground potential, and a voltage obtained by superimposing a video signal voltage on a voltage of about 100 V is applied to the cathode K to seal the end of the neck 14 of the funnel 11 respectively. Is supplied through a stem pin 27 that penetrates the stem 26.

By the application of the voltage, in the electron gun 16, the cathode K and the first to fourth electrodes G 1 to G 4 sequentially adjacent to the cathode K form a triode portion GE for generating an electron beam. The fifth lens G4, G5 forms a main lens ML that focuses the electron beam generated in the triode GE on the phosphor screen.

In the triode GE, the cathode K
When a voltage obtained by superimposing a video signal voltage on a voltage of about 100 V is applied to the
The electron beam is extracted from the cathode K by penetrating in the direction. This electron beam is applied to the second electrode G as shown in FIG.
A crossover 29 is formed in the vicinity of 2 and thereafter the light is incident on the third electrode G3 while diverging. In this case, the second electrode G
2 includes electron beam passage holes 20B, 20B of the first electrode G1.
Since a pair of fine apertures 21a and 21b are formed for G and 20R (only 20G is shown), two electron beams 15a and 15b having a small diameter are formed. 15b passes through the second electrode G2. The two electron beams 15 passing through the second electrode G2
a and 15b are the electron beam passage holes 20B of the first electrode G1.
, 20G, and 20R undergo a focusing action in the axial direction passing through the centers of the second electrode G2 and the third electrode G3.
Is larger than the pre-focus portion between the first and second electrodes G1 and G2, the two electron beams 15a
, 15b are focused and concentrated in the axial direction passing through the centers of the electron beam passage holes 20B, 20G, 20R of the first electrode G1. And the fourth and fifth electrodes G4
, G5 to be focused by the main lens ML.

Therefore, when the electron gun 16 is configured as described above, the diameter of the beam spot can be reduced without changing the intensity of the electron beam itself and without lowering the brightness on the screen, and the resolution is high and the reliability is high. It is possible to construct a color picture tube having high performance.

In the above-described embodiment, the electron beam passage hole of the second electrode is constituted by a set of two fine holes. However, the electron beam passage hole of the second electrode is constituted by a set of two holes. The holes are not limited to the holes. For example, as shown in FIG. 5, six fine circular holes provided rotationally symmetrically with respect to an axis passing through the centers of the three electron beam passage holes of the first electrode. 21
a to 21f.

As described above, the electron beam passage holes 22B, 22G, and 22R of the second electrode G2 are formed into the six openings 21a to 21f.
The size of each of the openings 21a to 21f is the same, and the total area (sum of the areas) of each of the openings 21a to 21f is the size of the electron beam passage hole of the second electrode of the conventional electron gun. That is, when the area of the electron beam passage hole of the first electrode is substantially the same, the diameter of the beam spot can be reduced without lowering the luminance on the screen, as in the above embodiment. Moreover, by making the total area of the six openings 21a to 21f constituting the electron beam passage holes of the second electrode G2 substantially equal to the area of the electron beam passage holes of the first electrode, each of the openings 21a to 21f can be formed. By making the diameter of the electron beam passing through smaller, the diameter of the beam spot on the screen can be further reduced.

In the above embodiment, the opening of the second electrode is circular. However, the shape of the opening is not limited to a circle, and the position of the opening is preferably rotationally symmetric. The formation position is not particularly limited.

In the above embodiment, the triode portion of the electron gun is constituted by the cathode and the first to fourth electrodes. However, as shown in FIG. 6, the triode portion GE is connected to the cathode K and the cathode K. The first to third electrodes G1 to G3 may be sequentially adjacent to each other.

Further, in the above embodiment, the second
Although only the electron beam passage hole of the electrode was constituted by a plurality of sets of fine openings, as shown in FIG.
2, G3 electron beam passage holes 22B, 22G, 22R,
31B, 31G, 31R (only 22G and 31G are shown)
May be constituted by the same number of fine apertures, each of which is one set.

In this case, the plurality of apertures may be shaped to form a multipole lens as well as a circle.

Further, in the above embodiment, a color picture tube provided with a BPF type electron gun has been described. However, the present invention relates to a UPF (Uni-Potential Focus) type electron gun and a QP type electron gun.
The present invention can also be applied to a color picture tube provided with another type of electron gun, such as an F (Quadra-Potential Focus) type electron gun. Also, the present invention can be applied to a color picture tube having a dynamic focus type electron gun.

[0042]

According to the present invention, a triode section including a cathode and a plurality of electrodes including a first electrode and a second electrode arranged adjacent to the cathode in the direction of a target, and an electron beam generated by the triode section is applied to the target. In a color picture tube provided with an electron gun having a main lens portion formed by a plurality of electrodes focused on a triode portion, a plurality of fine apertures are formed in the second electrode with respect to one aperture of the first electrode. Is formed into a configuration in which a plurality of electron beams are generated by the fine apertures of the second electrode, and the plurality of electron beams are focused on the target by the main lens unit and are united and concentrated. The plurality of fine openings of the second electrode are formed rotationally symmetrically with respect to a central axis passing through the center of the opening of the first electrode. When the total area of the plurality of fine apertures of the second electrode is substantially equal to the aperture area of the first electrode, the intensity of the electron beam itself is not changed and the brightness on the screen is reduced. Therefore, the diameter of the beam spot can be reduced, and a color picture tube with high resolution and high reliability can be constructed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an electron gun of a color picture tube which is an embodiment of the present invention.

FIG. 2A is a diagram illustrating a configuration of a first electrode of the electron gun, and FIG. 2B is a diagram illustrating a configuration of a second electrode.

FIG. 3 is a diagram showing a configuration of a color picture tube which is an embodiment of the present invention.

FIG. 4 is a diagram for explaining the operation of the electron gun shown in FIG.

FIG. 5 is a diagram showing a configuration of a second electrode different from the second electrode of the electron gun shown in FIG. 2 (b).

FIG. 6 is a view for explaining an electron gun having a configuration different from that of the electron gun shown in FIG. 1 and its operation.

FIG. 7 is a view for explaining an electron gun having a configuration further different from that of the electron gun shown in FIG. 6 and its operation.

8A is a diagram for explaining the action of a pincushion-type horizontal deflection magnetic field on an electron beam, and FIG.
(B) is a diagram for explaining the shape of the beam spot.

FIG. 9 is a view showing a configuration of a conventional electron gun of a color picture tube.

FIG. 10A is a diagram illustrating a configuration of a third electrode of the conventional electron gun, and FIG. 10B is a diagram illustrating a configuration of a fourth electrode.

[Explanation of symbols]

 15a, 15b: fine electron beam 15B: center beam 15G, 15R: pair of side beams 16: electron gun 20B, 20G, 20R: electron beam passage holes 21a, 21b of first electrode 21a, 21b: apertures 22B, 22G, 22R: first Electrode beam passage holes of two electrodes 31B, 31G, 31R ... electron beam passage holes of third electrode G1 ... first electrode G2 ... second electrode G3 ... third electrode G4 ... fourth electrode G5 ... fifth electrode GE ... triode portion K: cathode ML: main lens

Claims (4)

[Claims] 1. A triode portion comprising a cathode and a plurality of electrodes including a first electrode and a second electrode which are arranged adjacent to the cathode in the direction of a target, and an electron beam generated in the triode portion is supplied to the target. In a color picture tube provided with an electron gun having a main lens portion formed by a plurality of electrodes converging thereon, the triode portion has a plurality of holes on the second electrode with respect to one opening of the first electrode. A fine opening is provided, and this second
A plurality of electron beams are generated by the fine apertures of the electrodes, and the plurality of electron beams are formed to be focused and united and concentrated on the target by the main lens unit. Color picture tube. 2. The color picture tube according to claim 1, wherein the plurality of fine apertures of the second electrode are formed rotationally symmetric with respect to a central axis passing through the center of the aperture of the first electrode. . 3. The color picture tube according to claim 1, wherein the plurality of fine openings of the second electrode are formed in the same size. 4. The color picture tube according to claim 1, wherein the total area of the plurality of fine apertures of the second electrode is substantially equal to the aperture area of the first electrode.