JP2960498B2 - Color picture tube equipment - Google Patents

Description

The present invention relates to a color picture tube device, and more particularly to a color picture tube device in which distortion of an electron beam due to deflection is improved.

(Prior Art) Generally, as shown in FIG. 11, a color picture tube has an envelope composed of a panel (1) and a funnel (2) integrally joined to the panel (1). (1)
A phosphor screen (3) formed of a three-color phosphor layer emitting blue, green, and red colors is formed on the inner surface, and a large number of electron beam passage holes are formed inside the phosphor screen (3) so as to face the phosphor screen (3). The formed shadow mask (4) is mounted. An electron gun (7) for emitting three electron beams (6B), (6G) and (6R) into the neck (5) of the funnel (2).
And deflects the electron beams (6B), (6G), and (6R) emitted from the electron gun (7) by a magnetic field formed by a deflecting device (8) mounted outside the funnel (2). The phosphor screen (3) is horizontally and vertically scanned to display a color image.

In such a color picture tube, in particular, an electron gun (7)
In a row consisting of a center beam (6G) passing through the same horizontal plane and a pair of side beams (6B) and (6R)
An in-line type electron gun that emits electron beams (6B), (6G), and (6R). On the other hand, the magnetic field generated by the deflecting device (8) is an asymmetrical one consisting of a pincushion-type horizontal deflection magnetic field and a barrel-type vertical deflection magnetic field. A self-convergence type in-line color picture tube for self-concentrating the three electron beams (6B), (6G), and (6R) arranged in a line as a magnetic field is widely used.

In general, a color picture tube requires three electron beams (6) to improve the image drawn on the phosphor screen (3).
It is necessary to properly focus and concentrate B), (6G), and (6R) on the phosphor screen (3). The focusing of these three electron beams (6B), (6G), (6R), The concentration is the same for the self-convergence type in-line type color picture tube.

Regarding the concentration of the three electron beams (6B), (6G), and (6R), U.S. Pat. No. 2,957,106 discloses a means for preliminarily inclining and focusing the three electron beams emitted from the electron gun. U.S. Pat. No. 3,772,554 shows a means for eccentrically setting the side beam aperture of one grid constituting the electron gun slightly outside the side beam aperture of an adjacent grid.

However, even if the color picture tube is configured as described above, as the size and quality of the tube increase, (a) the beam spot diameter on the phosphor screen (b) the periphery of the phosphor screen due to the deflection magnetic field (C) New problems such as the concentration of three electron beams over the entire screen have been highlighted.

That is, for example, when the tube becomes large, the distance from the electron gun to the phosphor screen increases, the electron optical magnification of the electron lens increases, the beam spot diameter on the phosphor screen increases, and the resolution deteriorates. . In order to reduce the beam spot diameter on the phosphor screen, the lens performance of the electron gun must be improved. In order to improve the concentration over the entire screen, 3
It is good to make the interval of the electron beam small, and the present inventors have
We have developed and applied for an electron gun that solves these problems.

However, even in such an electron gun, when the amount of deflection increases, for example, as the size of the tube increases, the electron beam receives a larger deflection aberration, thereby distorting the beam spot around the phosphor screen and causing the deflection aberration. The problem cannot be solved sufficiently.

Normally, even if the magnetic field of the deflecting device is close to uniform, a slight pincushion-type magnetic field component or a barrel-type magnetic field component causes, for example, as shown in FIG. Beam (6B), (6G),
(6R) exerts the force indicated by the arrow (11). The force acting on the electron beams (6B), (6G), and (6R) increases as the tube becomes larger or wide-angle deflected. In particular, the vertical direction (Y-axis direction) becomes over-focused, As shown in Fig. 13, the electron beam (6B), (6G), and (6R) beam spots on the phosphor screen are composed of a high-brightness core (12) whose major axis is in the horizontal direction (X-axis direction). A halo (13) is generated in the vertical direction.

Conventionally, as a means for solving such a beam spot distortion based on the deflection aberration, there is a method in which a quadrupole lens is used to diverge the electron beam in the vertical direction according to the amount of deflection. However, when the quadrupole lens increases the vertical divergence, the horizontal focusing also increases.
When a polar lens is used, there is a problem that a means for canceling overfocusing in the horizontal direction is required.

As another means for solving the above-mentioned deflection aberration, a substantially horizontally elongated opening through which three electron beams pass in common is formed on the facing surface of at least two adjacent grids facing each other, and between the grids. There is a means for forming a so-called parallel plate lens that focuses each electron beam only in the vertical direction by giving a potential difference, and changing the convergence by the parallel plate lens according to the amount of deflection to solve the deflection aberration. However, it is difficult to cause the parallel plate lens to have a converging function only in the vertical direction, and a converging function also works in the horizontal direction, so that the interval between a pair of side beams among the three electron beams changes. That is, if the convergence effect of the parallel plate lens is made variable in accordance with the amount of deflection, there is a problem that the concentration state of the three electron beams changes in the central portion and the peripheral portion of the screen.

(Problems to be Solved by the Invention) As described above, the electron gun 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 the three electron beams are pincushioned horizontally. 2. Description of the Related Art A self-convergence type in-line type color picture tube in which three electron beams are self-concentrated by being deflected by a non-uniform magnetic field including a deflection magnetic field and a barrel type vertical deflection magnetic field is widely used. However, in the self-convergence type in-line type color picture tube, the beam spot is distorted due to the deflection aberration based on the non-uniform magnetic field, and the distortion of the beam spot leads to an increase in the size and quality of the tube. This poses a problem.

As a means for resolving distortion in the beam spot caused by this deflection aberration, a substantially horizontally elongated opening through which three electron beams pass in common is formed on the opposing surfaces of at least two adjacent grids. There is a method of forming a parallel plate lens that focuses each electron beam only in the vertical direction by giving a potential difference between the grids. However, the parallel plate lens focuses the electron beam not only in the vertical direction but also in the horizontal direction, and particularly, the interval between the pair of side beams changes. Therefore, if the focusing action of the parallel plate lens is made variable in accordance with the amount of deflection, there is a problem that the concentration of the three electron beams changes at the central portion and the peripheral portion of the screen.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. In an in-line type electron gun, the focusing action of a parallel plate lens in the arrangement direction of three electron beams (for example, in the horizontal direction) is changed to the arrangement direction of three electron beams. Even if the focusing action in the orthogonal direction (for example, vertical direction) is made weaker and the focusing action of the parallel plate lens is made variable in accordance with the amount of deflection, there is no change in the interval between the pair of side beams, and the three electron beams are spread over the entire screen. It is an object of the present invention to provide a color picture tube apparatus that appropriately focuses and concentrates, reduces distortion of a beam spot based on deflection aberration, and displays a good image.

[Means for Solving the Problems] Electron beam formation for controlling electron emission from a cathode and accelerating and converging the emitted electrons to form three electron beams arranged in a line passing on the same plane. And an electron gun having an electron lens unit composed of a plurality of grids for focusing and concentrating the three electron beams emitted from the electron beam forming unit on the phosphor screen. In a color picture tube device for deflecting an electron beam by a deflecting device to scan a phosphor screen horizontally and vertically, the electron lens portion is elongated in the arrangement direction of the three electron beams and arranged in the central portion in the arrangement direction of the three electron beams. At least two adjacent cylindrical electrodes each having an opening common to the three electron beams, the diameter of which in the direction perpendicular to the direction is smaller than the diameter in the same direction at both ends. Be more formed by a potential difference applied between these cylindrical electrodes, it showed a strong focusing action in the direction orthogonal to the arrangement direction of the three electron beams, and by a potential difference applied in synchronism with the deflection of the deflection device,
An electron lens for focusing the three electron beams was provided over the entire area of the phosphor screen.

In addition, at least two adjacent cylindrical electrodes are common to the three electron beams which are elongated in the arrangement direction of the three electron beams and whose diameter in the direction orthogonal to the arrangement direction of the three electron beams is smaller than the diameter in the same direction at both ends. An electric field control piece folded inside the electrode was provided on both sides of the central portion of the opening in the direction orthogonal to the arrangement direction of the three electron beams.

(Function) As described above, the three electron beams are elongated and arranged in the arrangement direction of the three electron beams so that the three electron beams arranged in a line pass in common to the electron lens portion which focuses and concentrates the three electron beams on the phosphor screen. A diameter in a direction perpendicular to the arrangement direction is smaller than a diameter in the same direction at both ends. The electron beam is formed by at least two cylindrical electrodes having openings common to three electron beams. When an electron lens which exhibits a strong focusing action in a direction orthogonal to the arrangement direction of the three electron beams and focuses the three electron beams over the entire area of the phosphor screen by a potential difference applied in synchronization with the deflection of the deflection device is provided, The electric field penetrating the inside of each electrode has a small curvature of the equipotential surface in a direction orthogonal to the arrangement direction of the three electron beams, penetrates deeply into each electrode, and The focusing action in the direction orthogonal to the arrangement direction of the arms can be enhanced. On the other hand, in the arrangement direction of the three electron beams, since the diameter in the direction orthogonal to the arrangement direction of the three electron beams at both ends of the opening is larger than the diameter in the same direction at the center, the electric field and the like penetrating into both ends are different. Since the curvature of the potential surface becomes large and does not penetrate deeply into each electrode, the focusing action of the three electron beams in the arrangement direction can be weakened. Therefore, the three electron beams can be strongly focused by the at least two adjacent electrodes in a direction orthogonal to the arrangement direction and hardly focused in the arrangement direction, and change the interval between the pair of side beams. The three electron beams can be focused without focusing, and the three electron beams can be properly focused and concentrated, and the distortion of the beam spot caused by the deflection aberration can be easily reduced over the entire phosphor screen. it can.

In particular, at least two adjacent cylindrical electrodes are elongated in the direction in which the three electron beams are arranged, and the diameter in the direction orthogonal to the direction in which the three electron beams are arranged in the center is smaller than the diameter in the same direction at both ends. By providing electric field control pieces folded inside the electrode at both sides of the center of the aperture in the direction orthogonal to the arrangement direction of the three electron beams, the aperture shape and the electric field control pieces penetrate inside each grid. The generated electric field has a smaller curvature of the equipotential surface in a direction orthogonal to the arrangement direction of the three electron beams, penetrates deep into each electrode, and further enhances the focusing action in the direction orthogonal to the arrangement direction of the three electron beams. Can be. On the other hand, in the arrangement direction of the three electron beams, the diameter in the direction perpendicular to the arrangement direction of the three electron beams at both ends of the opening is larger than the diameter in the same direction at the center, and there are no electric field control pieces at both ends. Therefore, the curvature of the equipotential surface of the electric field penetrating into both ends becomes large, and the electric field does not penetrate deeply into each electrode, so that the focusing action of the three electron beams in the arrangement direction can be weakened. Therefore, the three electron beams can be strongly focused by the at least two adjacent grids in a direction orthogonal to the arrangement direction and hardly focused in the arrangement direction,
The three electron beams can be focused without changing the distance between the pair of side beams, so that the three electron beams can be appropriately focused and concentrated, and the distortion of the beam spot caused by the deflection aberration can be more easily achieved. Can be reduced over the entire phosphor screen.

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

FIG. 3 shows a color picture tube device according to one embodiment. This color picture tube device has an envelope composed of a panel (1) and a funnel-like funnel (2) integrally joined to the panel (1), and the inside of the panel (1) has blue and green colors. A phosphor screen (3) made of a three-color phosphor phase striped in the vertical direction and emitting red light is formed, and a large number of slit-like electrons are provided inside the phosphor screen (3) in opposition to the phosphor screen (3). A shadow mask (4) having a beam passage hole is mounted. An inner conductive film (20) is applied and formed on the inner surface of the funnel (2), and a center beam (21G) and a pair of side beams (21G) passing on the same horizontal plane are formed in a neck (5) of the funnel (2). 3 in a single row consisting of 21B) and (21R)
An in-line type electron gun (22) for emitting electron beams (21B), (21G), and (21R) is provided. Furthermore,
A pincushion-type horizontal deflection magnetic field and a barrel-type vertical deflection for horizontally and vertically deflecting the three electron beams (21B), (21G), and (21R) emitted from the electron gun (21) outside the funnel (2). Deflection device for generating magnetic field (8)
Is installed.

As shown in FIGS. 1 and 2, the electron gun (22) has three cathodes () arranged in a row in the horizontal direction on the side of the stem (24) for sealing the end of the neck (5). K), three heaters (H) interposed in the cathode (K), and first to eighth grids (G1) which are sequentially arranged in the direction of the phosphor screen (3) adjacent to the cathode (K). )
To (G8), which are integrally fixed by a pair of insulating supports (25), and the convergence cup (C) is attached to the phosphor screen (3) side of the eighth grid (G8). The structure is formed. Then, a plurality of stem pins (26) which are airtightly penetrated through the system part (24) and a plurality of pressure-contacted inner conductive films (20) which are welded to the side walls of the convergence cup (C) and applied and formed on the inner surface of the funnel (2). The valve spacer (27) supports the inside of the neck (5).

The first and second grids (G1) and (G2) adjacent to the cathode (K) are composed of relatively thin plate-like electrodes having an integral structure, and these grids (G1) and (G2) are arranged in a single line. Three relatively small apertures are formed in one row corresponding to the three cathodes (K). The third grid (G3) is composed of a combination of a plate-shaped electrode having a relatively large thickness and a cup-shaped electrode, and the cup-shaped electrode on the second grid (G2) side has the first and second grids. (G1),
Three apertures larger than the aperture of (G2) are formed.
In addition, the plate-like electrode located on the fourth grid (G4) side includes:
As shown in FIG. 4, three openings (29) larger than the openings of the cup-shaped electrode are formed. The fourth grid (G4) is composed of a relatively thick plate-like electrode in which three similar openings are formed. The fifth grid (G5)
It consists of a combination of a relatively thick plate-like electrode and a cylindrical electrode consisting of a combination of a cup-like electrode. The plate-like electrode on the fourth grid (G4) side has three similar openings. Are formed. On the other hand, the cup-shaped electrode (30) on the sixth grid (G6) side has the structure shown in FIG.

That is, in the cup-shaped electrode (30) on the sixth grid (G6) side, an opening (31) common to the three electron beams that is elongated in the horizontal direction (the arrangement direction of the three electron beams) is formed.
The diameter in the vertical direction (the direction orthogonal to the arrangement direction of the three electron beams) of the central portion through which the three electron beams pass is smaller than the diameter in the vertical direction of both ends. Further, in the opening (31) of the cup-shaped electrode (30), the sides on both sides of the central portion in the vertical direction perpendicular to the arrangement direction of the three electron beams are folded substantially parallel to the inside of the electrode (30). An electric field control piece (32) is provided.

The sixth grid (G6) is the fifth grid (G
The combination of the cylindrical electrode of 5) and a cylindrical electrode composed of a combination of cup-shaped electrodes having the same structure, the cup-shaped electrode on the fifth grid (G5) side and the seventh grid (G7)
The side cup-shaped electrode is formed with a horizontally elongated opening like the opening (31) of the cup-shaped electrode (30). The seventh grid (G7) is composed of a combination of a cylindrical electrode made of a combination of cup-shaped electrodes and a thick plate-shaped voltage. The cup-shaped electrode on the sixth grid (G6) side is made of Like the five-grid (G5) cup-shaped electrode (30), it is formed in a structure having a horizontally elongated hole. As shown in FIG. 6, three elliptical apertures (33) that are long in the vertical direction are formed in a row in the plate-like electrode on the eighth grid (G8) side. The eighth grid (G8) is composed of a plate-like electrode, and has three elliptical openings that are long in the vertical direction, similar to the plate-like electrode of the seventh grid (G7). However, out of the three openings arranged in a row in the eighth grid (G8), the openings on both sides are eccentric to the outside in the horizontal direction with respect to the openings on both sides of the plate electrode of the seventh grid (G7). I have.

The following voltages are applied to this electron gun. That is, a cutoff voltage of about 150 V and a video signal are applied to the cathode (K), the first grid (G1) is set to the ground potential, the second grid (G2) is set to 500 V to 1 kV, and the third grid ( G3) 5-10kV, 4th grid (G4) 500V-1k
V, an anode voltage of 5 to 10 kV is applied to the fifth and seventh grids (G5) and (G7), an anode voltage of 15 to 20 kV to the sixth grid (G6), and an anode voltage of 25 to 35 kV to the eighth grid (G8). further,
The sixth grid (G6) is applied with a dynamic voltage VD that changes according to the deflection of the electron beam as shown by a curve (35) in FIG. 7 using the above voltage as a reference voltage.

Of the voltages applied to the electrodes of the electron gun, the anode voltage of the eighth grid (G8) was applied and formed from an anode terminal (not shown) provided on the side wall of the funnel (2). The voltage is applied via the valve spacer (27) and the convergence cup (C) attached to the inner conductive film (20) and the convergence cup (C) and pressed against the inner conductive film (20), and the other cathode (K ) And the first to seventh grids (G1) to (G7) are applied through a plurality of stem pins (26) which hermetically penetrate the stem portion (24).

By applying the voltage, the cathode (K) and the first,
The second grids (G1) and (G2) form an electron beam forming unit that controls electron emission from the cathode (K) and accelerates and focuses the emitted electrons to form an electron beam. And the third, fourth and fifth grids (G3), (G4),
(G5) forms a unipotential type sub lens, and the fifth, sixth, and seventh grids (G5), (G6), and (G7)
Is formed with a unipotential electron lens whose lens intensity changes with the dynamic voltage VD applied to the sixth grid (G6).

In particular, the fifth, sixth and seventh grids (G5), (G6),
The electron lens formed by (G7) forms a so-called parallel plate lens based on the aperture shape of each of the grids (G5), (G6), and (G7) which are elongated in the horizontal direction. Depending on the shape and the electric field control piece (32), the electric field penetration state differs between the horizontal direction and the vertical direction. That is, as shown in FIG. 8 (a), the hole diameter is smaller in the vertical direction than in the horizontal direction, and the hole diameter (3
Since the electric field control pieces (32) whose side edges are folded into the electrode are provided on both sides in the vertical direction of 1), the vertical electric field penetrating into the electrode has a curvature of the equipotential surface (36a). small,
Therefore, a strong focusing action is exerted on the electron beam. On the other hand, as shown in FIG.
The vertical electric field at both ends of the electrode is larger than that at the center, and the electric field control pieces (32) are not provided at both ends. 36
b) has a large curvature and therefore has a weak focusing effect on the electron beam. That is, the fifth, sixth, seventh
The parallel plate lenses formed by the grids (G5), (G6) and (G7) are electron lenses that focus three electron beams only in the vertical direction.

Further, between the seventh and eighth grids (G7) and (G8), the grids (G7) and (G8) each have a vertically long opening (33), so that the horizontal focusing is achieved. A main lens consisting of a so-called astig lens is formed, whose action is stronger than the focusing action in the vertical direction. In addition, since the apertures on both sides of the eighth grid (G8) are eccentric to the outside in the horizontal direction with respect to the apertures on both sides of the seventh grid (G7), the main lens has a pair of apertures passing through the apertures on both sides. The side beam is deflected in the direction near the center beam passing through the central aperture,
It is an electron lens that focuses three electron beams at the same time as focusing.

Therefore, in the above-described electron gun, electrons emitted from the cathode (K) in accordance with the video signal are converted to the cathode (K).
A crossover is formed by the first and second grids (G1) and (G2) to form an electron beam, which is slightly focused by the prefocus lens formed by the second and third grids (G2) and (G3). Into the third grid (G3) while diverging. This electron beam is then applied to the sub-lens formed by the third to fifth grids (G3) and (G5), the parallel plate lens formed by the fifth to seventh grids (G5) to (G7), and the seventh lens. , The eighth grid (G
7) Focused and concentrated by the main lens formed by (G8) and focused on the phosphor screen (3),
concentrate.

The color picture tube deflects the electron beam by the magnetic field of the deflecting device and projects a color image by scanning the phosphor screen (3) horizontally and vertically. In this case, when deflecting to the center of the phosphor screen (3), a crossover (38) is formed by the first and second grids as shown in the center beam (21G) in FIG. The center beam (21G) slightly focused by the pre-focus lens formed by the second and third grids and entering the third grid is the third to fifth center beams.
The light is slightly focused in the horizontal and vertical directions by the unipotential type sub lens LS formed by the grid, and then focused only in the vertical direction by the parallel plate lens LP formed by the fifth to seventh grids. The main lens LM formed by the eighth and eighth grids converges and concentrates in the horizontal and vertical directions.

On the other hand, when deflecting to the periphery of the phosphor screen (3), the dynamic voltage VD applied to the sixth grid is increased according to the amount of deflection of the center beam (21G) to focus the parallel flat lens LP. By weakening the action, the object point moves from (39a) to (39b) on the phosphor screen (3) side as shown by the dashed line in FIG. The beam spot is in an insufficient focusing state. However, the deflection aberration of the deflecting magnetic field composed of the non-uniform magnetic field causes the electron beam to be in an over-focusing state as described above, so that the deflecting magnetic field cancels out this deficient focusing, and as shown in FIG. 9 (b), The center beam (21G) can be optimally focused on the phosphor screen (3).

Although the center beam (21G) is shown in FIG. 9, the operation of each lens of the electron gun is the same for a pair of side beams.

Therefore, with the above configuration, it is possible to optimally focus and concentrate the three electron beams arranged in a line over the entire area of the screen, to reduce the distortion of the beam spot on the phosphor screen (3), A color picture tube device for displaying an image can be provided.

In the above embodiment, the electric field control piece is provided on the fifth, sixth, and seventh grids forming the parallel plate lenses, the cup electrodes having the horizontally elongated openings formed therein, as shown in FIG. The fifth, sixth,
The cup-shaped electrode of the seventh grid, as shown in FIG.
A parallel flat plate that is elongated in the horizontal direction and has only the opening (31) whose vertical diameter at the center is smaller than the diameter in the same direction at both ends and has no electric field control piece. A lens can be formed.

In the above embodiment, the parallel plate lens is constituted by a unipotential lens.
A high unipotential lens or a bipotential lens may be used.

Further, the present invention can be applied to all electron guns including a parallel plate lens that strongly focuses an electron beam in one of the horizontal and vertical directions and extremely weakens the other.

[Effects of the Invention] An electron lens portion which converges and concentrates three electron beams arranged in a line on the same plane on the phosphor screen is elongated in the arrangement direction of the three electron beams and arranged in the central portion with the arrangement direction of the three electron beams. At least two adjacent cylindrical electrodes having holes common to three electron beams whose diameters in the direction perpendicular to each other are smaller than the diameters in the same direction at both ends are formed by the potential difference given between these cylindrical electrodes. An electron lens that exhibits a strong focusing action in a direction orthogonal to the arrangement direction of the electron beams and that focuses the three electron beams on the entire surface of the phosphor screen by a potential difference given in synchronization with the deflection of the deflection device, The electric field penetrating into the inside of each electrode has a small curvature of the equipotential surface in a direction orthogonal to the arrangement direction of the three electron beams, and penetrates deeply into each electrode.
The focusing action in the direction orthogonal to the direction in which the electron beams are arranged can be enhanced. On the other hand, in the arrangement direction of the three electron beams, since the diameter in the direction orthogonal to the arrangement direction of the three electron beams at both ends of the opening is larger than the diameter in the same direction at the center, the electric field and the like penetrating into both ends are different. Since the curvature of the potential surface becomes large and does not penetrate deeply into each electrode, the focusing action of the three electron beams in the arrangement direction can be weakened.
Therefore, the three electron beams can be strongly focused by the at least two adjacent electrodes in a direction orthogonal to the arrangement direction and hardly focused in the arrangement direction, and change the interval between the pair of side beams. The three electron beams can be focused without focusing, and the three electron beams can be properly focused and concentrated, and the distortion of the beam spot caused by the deflection aberration can be easily reduced over the entire phosphor screen. it can.

In particular, at least two adjacent cylindrical electrodes are elongated in the direction in which the three electron beams are arranged, and the diameter in the direction orthogonal to the direction in which the three electron beams are arranged in the center is smaller than the diameter in the same direction at both ends. By providing electric field control pieces folded inside the electrode at both sides of the center of the aperture in the direction orthogonal to the arrangement direction of the three electron beams, the aperture shape and the electric field control pieces penetrate inside each grid. The electric field generated has a smaller curvature of the equipotential surface in a direction orthogonal to the arrangement direction of the three electron beams, penetrates deeply into each electrode, and further strengthens the focusing action in the direction orthogonal to the arrangement direction of the three electron beams. Can be. On the other hand, in the arrangement direction of the three electron beams, the diameter in the direction perpendicular to the arrangement direction of the three electron beams at both ends of the opening is larger than the diameter in the same direction at the center, and there are no electric field control pieces at both ends. Therefore, the curvature of the equipotential surface of the electric field penetrating into both ends becomes large, and the electric field does not penetrate deeply into each electrode, so that the focusing action of the three electron beams in the arrangement direction can be weakened. Therefore, the three electron beams can be strongly focused by the at least two adjacent grids in a direction orthogonal to the arrangement direction and hardly focused in the arrangement direction,
The three electron beams can be focused without changing the distance between the pair of side beams, so that the three electron beams can be appropriately focused and concentrated, and the distortion of the beam spot caused by the deflection aberration can be more easily achieved. Can be reduced over the entire phosphor screen.

In addition, in such a color picture tube device, unlike the case of using a quadrupole lens as the electron lens for correcting the deflection aberration of the deflection magnetic field, there is no need to correct the convergence of the three electron beams in the arrangement direction. There is an advantage that the design is easy and easy to use.

[Brief description of the drawings]

1 to 10 are explanatory views of an embodiment of the present invention. FIG. 1 is an XZ sectional view showing a configuration and an arrangement of an electron gun according to the embodiment, and FIG. FIG. 3 is a view showing the structure of a color picture tube apparatus as an embodiment of the present invention, and FIG. 4 is a view showing the aperture shape of a relatively thick plate-like electrode of a third grid. FIG. 5 is a perspective view showing the structure of the cup-shaped electrode of the fifth grid, FIG. 6 is a plan view showing the aperture shape of the thick plate-shaped electrode of the seventh grid, and FIG. FIGS. 8 (a) and (b) show the horizontal and vertical electric field distributions of the parallel plate lens, respectively, and FIGS. 9 (a) and 9 (b) show the dynamic voltage waveforms applied to the six grids. FIG. 10 is an equivalent optical model diagram for explaining the operation of the electron gun, and FIG. FIG. 11 is a perspective view showing a different structure of a top electrode, FIG. 11 is a view showing a configuration of a conventional color picture tube, and FIG.
FIG. 12 is a view for explaining the action of the pincushion-type magnetic field on the electron beam, and FIG. 13 is a view showing the shape of a beam spot distorted by the pincushion-type magnetic field. 3 ... Phosphor screen, 8 ... Deflecting device, 21B, 21R ... A pair of side beams, 21G ... Center beam, 22 ... Electron gun, 26 ... Stem pin, 27 ... Valve spacer, 29 ... Open Hole, 30: Cup-shaped electrode of fifth grid, 31: Opening, 32: Electric field control piece, 33: Opening, K: Cathode, G1: First grid, G2: Second grid G3: third grid, G4: fourth grid, G5: fifth grid, G6: sixth grid, G7: seventh grid, G8: eighth grid, H: heater.

Continuation of the front page (72) Inventor Jiro Shimokawabe 1-9-2 Hara-cho, Fukaya-shi, Saitama Prefecture Inside the Toshiba Fukaya CRT factory (56) References JP-A-3-20937 (JP, A) JP-A Heihei 3-110739 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 29/46-29/68

Claims (2)

(57) [Claims] An electron beam forming unit for controlling electron emission from a cathode and accelerating and converging emitted electrons to form three electron beams arranged in a line in a line on the same plane, and from the electron beam forming unit. An electron gun having an electron lens unit composed of a plurality of grids for focusing and concentrating the three electron beams emitted on the phosphor screen is provided. The three electron beams emitted from the electron gun are deflected by a deflecting device. In the color picture tube device for horizontally and vertically scanning the phosphor screen, the electron lens portion is elongated in a direction in which the three electron beams are arranged and has a diameter in a direction perpendicular to the direction in which the three electron beams are arranged in a central portion at both ends. Formed by at least two adjacent cylindrical electrodes having openings common to the three electron beams smaller than the diameter in the same direction in the portion. Due to the potential difference given between the poles, a strong focusing action is provided in the direction orthogonal to the arrangement direction of the three electron beams, and the three electron beams are spread over the entire phosphor screen by the potential difference given in synchronization with the deflection of the deflecting device. A color picture tube device comprising an electron lens for focusing light. 2. The method according to claim 1, wherein the at least two adjacent cylindrical electrodes are elongated in the direction in which the three electron beams are arranged, and the diameter of the central portion in the direction orthogonal to the direction of the arrangement of the three electron beams is smaller than the diameter in both ends at the same direction. 2. The color picture tube device according to claim 1, further comprising an electric field control piece folded inside the electrode on both sides of a central portion of the opening common to the three electron beams in a direction orthogonal to the arrangement direction of the three electron beams. .