JPH03110739A - Color image picture tube device - Google Patents

Abstract

PURPOSE:To reduce deflection abberation so as to better picture image performance of a color picture tube by constituting a main lens portion of at least three electron lenses consisting of a first lens for intensifying focusing strength in the vertical direction as the amount of deflection of an electron beam is increased, and a second lens for dispersing the electron beam in the vertical direction. CONSTITUTION:The main lens portion of an electron gun 22 comprises at least three electron lenses having a first lens G3 to G5 for intensifying focusing strength in the vertical direction as the amount of deflection of an electron beam is increased and a second lens G5 to G7 for dispersing the electron beam in the vertical direction as the amount of deflection is increased, and a third lens G7, G8. An electron beam is thereby correctly focused on a phosphor screen 6 regardless of deflection of the electron beam, and also when the electron beam passes through a deflected magnetic field the radius of the electron beam in its vertical direction is decreased as the amount of deflection is increased. Thus deflection abberation is decreased and the shape of a beam spot in the periphery of the screen is bettered.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Field of Industrial Application) This invention relates to a color picture tube device, and is particularly applicable to a wide deflection angle color picture tube or a high-quality color picture tube forming a horizontally long screen. The present invention relates to a color picture tube device that provides good resolution over the entire screen.

(Prior Art) In general, a color picture tube device, as shown in FIG. 9, has three electron beams (4B), (4G), (4R)
This electron beam (4B), (4G)
, (4R) by horizontal and vertical deflection magnetic fields formed by a deflection device (5) mounted on the outside of the envelope (1) to scan the phosphor screen (8) horizontally and vertically. It is assembled into a structure that displays color images. Note that (8) is a shadow mask facing the phosphor screen (6).

In such a color picture tube device, in particular, the electron gun (3) is an in-line type electron gun that emits a center beam (4G) and a pair of side beams (4B) and (4R) passing on the same horizontal plane; As shown in Figure (a), the horizontal deflection magnetic field (9) of the deflection device is made into a binction shape, and as shown in Figure (b), the vertical deflection magnetic field (10) is made into a non-uniform magnetic field distorted into a barrel shape. As a result, self-convergence type in-line color picture tube devices that self-converge three electron beams have become the mainstream color picture tube device for general use because they can easily reduce power consumption and improve picture tube quality and performance. ing.

However, this self-convergence type in-line color picture tube device has three electron beams (4B) as described above.
, (4G), (4R) by a nonuniform magnetic field, each electron beam (4B), (4G),
The cross-sectional shape of (4R) becomes distorted as the amount of deflection increases,
As shown in FIG. 11, even if the beam spot (12a) at the center of the screen (11) is adjusted to be almost a perfect circle,
The beam spot (12b) at the periphery of the screen is aligned horizontally (X
The shape has an elliptical high-brightness part (13) with a long sleeve in the axial direction) and a low-brightness part (14) long in the vertical direction (Y-axis direction), which significantly deteriorates the resolution of the peripheral part of the screen.

This distortion of the beam spot (12b) is caused by the binction-like horizontal deflection magnetic field and barrel-like vertical deflection magnetic field of the deflection device, which weakens the focus of the electron beam in the horizontal direction and conversely in the vertical direction within the asymmetric magnetic field. is caused by being strengthened.

By the way, as a method of reducing the deterioration in resolution due to this deflection distortion, there is a method of reducing the diameter of the electron beam passing through the main lens of the electron gun and the magnetic field of the deflection device.

This method is carried out by strongly focusing the electron beam with a prefocus lens of an electron gun inside the shell, but this method increases the crossover diameter and the beam spot diameter at the center of the screen. , resolution deteriorates.

Alternatively, the deflection distortion can be reduced by using an asymmetric prefocus lens and underfocusing the electron beam at the center of the screen. However, in this case, the beam spot at the center of the screen has an elliptical shape with a long sleeve in the vertical direction, so the resolution at the center of the screen deteriorates as in the above method.

Still another method is to improve the beam spot diameter at the periphery of the screen by changing the intensity of the electron lens in synchronization with the deflection of the electron beam, that is, by using a dynamic φ focusing method.

This dynamic focusing method includes a method of dynamically changing the vertical divergence angle with respect to the electron beam in a prefocus lens or sublens;
There is a method of dynamically changing the vertical focusing power of the main lens.

However, in both of these methods, the vertical diameter of the electron beam becomes larger when it is deflected toward the periphery of the screen than when it is deflected toward the center of the screen within the deflection magnetic field. There is a problem in that areas where the amount of light is large are subject to larger deflection aberrations, and the beam spot improvement effect becomes smaller. In addition, the deflection aberration experienced by this electron beam is larger in the horizontal deflection magnetic field than in the vertical deflection magnetic field, so it becomes a problem especially when scanning a horizontally long screen like a high-definition television at a wide deflection angle. At the outermost edge in the diagonal direction of the screen, the beam spot deteriorates and the resolution deteriorates.

The area in which the dynamic focus is not effective varies depending on the method and dimension of the electron gun and deflection device, and becomes a problem when the deflection angle is 90'' or more. In other words, as shown in Fig. 12(a) As shown in area (15), 110@ deflection, screen aspect ratio is 4:3
In the case of 110@polarization and the screen aspect ratio is IB:9, the total phosphor is about 10% of the screen (6), but as shown in area (15) in (b), the total phosphor is It accounts for about 20% of the screen (6), and becomes a big problem especially in color picture tube devices for high-definition televisions with an aspect ratio of 16:9, which requires high resolution up to the periphery of the screen.

(Problems to be Solved by the Invention) As described above, in the self-convergence type in-line color picture tube device that emits three electron beams passing on the same horizontal plane, each of the three electron beams is deflected by a non-uniform magnetic field. The cross-sectional shape of the electron beam is distorted as the amount of deflection increases, and the beam spot at the periphery of the screen has an elliptical high-brightness area that is long in the horizontal direction and a low-brightness area that is long in the vertical direction. There is a problem in that the resolution in the peripheral areas is significantly degraded. Conventionally, as a means to reduce this deterioration of resolution at the periphery of the screen, methods have been used to strongly focus the electron beam using a brifocal lens in the electron gun, or to use a brifocal lens as an asymmetric lens to reduce the magnetic field of the electron gun's main lens and deflection device. There are ways to reduce the diameter of the electron beam that passes through it, but none of them yield good results. Another method is to use a dynamic focus method to change the intensity of the electron lens in synchronization with the deflection of the electron beam. becomes large when it is deflected toward the periphery of the screen, so areas where the amount of electron beam deflection is large suffer from large deflection aberrations, making it difficult to obtain good results. In addition, the deflection aberration that this electron beam receives is larger in the horizontal deflection magnetic field than in the vertical deflection magnetic field, which becomes a problem when scanning a horizontally long screen like a high-definition television with a wide deflection angle. There is a problem that the beam spot deteriorates at the outermost part in the diagonal direction, and the resolution deteriorates.

This invention was made in view of the above problems, and
An object of the present invention is to configure a color picture tube device that has high resolution from the center of the screen to the outermost edge of the screen even when scanning a horizontally long screen at a wide deflection angle, such as in a high-definition television.

[Structure of the Invention] (Means for Solving the Problems) A cathode, a plurality of grids that control electron emission from the cathode to form an electron beam, and a plurality of grids constituting a main lens portion that focuses the electron beam. In a color picture tube device that has an electron gun consisting of a grid of The main lens portion includes at least a first lens that strengthens the focusing power in the vertical direction as the amount of deflection of the electron beam increases, and a second lens that diverges the electron beam in the vertical direction as the amount of deflection increases. It was composed of three electronic lenses.

(Function) By configuring the main lens part that focuses the electron beam as described above, it is possible to correctly focus the electron beam on the phosphor screen regardless of whether or not the electron beam is deflected, and the electron beam can be deflected by the deflection magnetic field. As the beam passes through the beam, its vertical diameter can be reduced as the amount of deflection increases, thereby reducing deflection aberrations and improving the shape of the beam spot at the periphery of the screen.

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

FIG. 1 shows a color picture tube device which is one embodiment of the present invention.

This color picture tube device has an envelope consisting of a panel (20) and a funnel (21).
) A shadow mask (not shown) having a large number of electron beam passage holes formed inside is attached, and facing the shadow mask, a panel (20) has three panels emitting light in blue, green, and red on its inner surface.
A phosphor screen (6) consisting of a color phosphor layer is formed. In addition, three electron beams arranged in rows are emitted into the neck (2) of the funnel (21), consisting of a center beam (4G) and a pair of side beams (4B) and (4R) passing on the same horizontal plane. Electron gun (22)
is installed. Furthermore, an electron beam (
4B), (4G), and (4R) in the horizontal direction and a barrel-shaped vertical deflection magnetic field that deflects in the vertical direction, a phosphor screen (6) is formed. A deflection device (5) is installed for horizontal and vertical scanning.

The electron gun (22) has three independent cathodes (K) arranged in a row in the horizontal direction, and a first integrated structure arranged in sequence from the cathodes (K) in the direction of the phosphor screen (6).
to eighth cruds (Gl) to (G8), which are fixed together by a pair of insulating supports (not shown).

Each of the above three cathodes (K) is equipped with a heater (
H) is interpolated, and heating of this heater (H) causes electron emission. 1st and 2nd crits (Gl),
(G2) consists of a plate-shaped electrode in which relatively small electron beam passing holes are formed corresponding to the three cathodes (K) arranged in the above-mentioned row. 3rd to 8th crits (G
3) to (G8) each consist of a cylindrical electrode, and on the second crid (G2) side of the third crid (G3),
As shown in FIG. 2, three relatively large electron beam passage holes (24) are formed corresponding to the three cathodes (K). Also, the 4th of this 3rd crid (G3)
As shown in Fig. 3, three electronic beams are installed on the clitoris (G4) side, the 6th clitoris (G6) side of the 4th clitoris (G4), the 5th clitoris (G5), and the 7th clitoris (G7). An electron beam passing hole (25) is formed in which the common horizontal diameter is about five times longer than the vertical diameter. In addition, on the sixth crid (G6) side, as shown in Fig. 4, three non-circular electron beam passing holes (2B) are formed whose vertical diameter is longer than the horizontal diameter. There is. Further, inside the seventh hand (G7), as shown in FIG. 5, a plate-shaped electrode (28) in which three non-circular electron beam passage holes (27) are formed is provided. ing.

The following voltages are applied to each electrode of this electron gun (22). For example, a video signal is superimposed on the cathode (K) with a cut-off voltage of about 150V, and the first cathode (K) is
G1) to ground potential, 500V to the second clip (G2)
1 kV, 5 to 1 OkV to the 3rd clip (G3), 2 to 1 OkV to the 4th clip (G4), 5 to 1 OkV to the 5th clip (G5)
5 to 1 OkV, 6th crid (GO) t: 2 to 10
kV, 7th crit (G7)! , : 5 to 10 kV, 8th clid (G8) i: l: An anode voltage of 25 to 30 kV is applied. Also, especially the 4th and 6th grid (
G4) and (GO) are applied with a dynamic voltage VD that changes in synchronization with the deflection of the electron beam, as shown by curve (30) in FIG. 6, with the above voltage as a reference.

The anode voltage of this eighth crid (G8) is the funnel (
An inner conductive film (31) formed on the inner surface of the funnel (21) from an anode terminal (not shown) provided on the side wall of the funnel (21)
and a valve spacer (3) welded to the side surface of the tip of the eighth crid (G8) and in pressure contact with the inner conductive film (31).
2), but the voltages of other grids (G1) to (G7) other than the heater (H), cathode (K) and eighth grid (G8) are applied through the sealing neck (2) end. A stem pin (3) that airtightly penetrates the stem portion (33)
4). In this case, the grids to which voltages of the same potential are applied, that is, the third, fifth, and seventh grids (G3), (G5), (G7), and the fourth and sixth grids (G4), (06) about,
It is preferable to connect them at the same potential within the pipe as shown in FIG. Further, the voltage applied to each of the above electrodes is controlled by a resistor placed in the neck (2) and connected to the eighth grid (G8) by this resistor.
The anode voltage applied to the electrode may be divided by resistance and applied.

By applying the above voltage, the cathode (K) and the first and second grids (al) and (G2) control electron emission from the cathode (K), resulting in electron beams (4B) and (4G).
, (4R). In addition, the above electron beams (48), (4G), (4R) are generated by the second and third grids (G2) and (G3).
A brifocal lens is formed that focuses the . Also,
3rd, 4th, 5th grid (G3), (G4),
(G5) constitutes a unipotential lens, but this unipotential lens has electron beam (4B), (
4G) and (4R) in the vertical direction, but not in the horizontal direction, forming a so-called parallel plate lens. Also, the 5th, 6th, and 7th grids (G5), (G8)
, (07) constitutes a unipotential lens, and this unipotential lens has electron beams (4B), (4G), (4R) from the shape of the electron beam passage hole shown in FIGS. 3 and 4. It forms a so-called quadrupole lens that diverges in the vertical direction but converges in the horizontal direction. Furthermore, the seventh and eighth grids (07), (0
8) constitutes a large-diameter lens that focuses and concentrates the three electron beams onto the phosphor screen (6). Especially a pair of side beams (4B), (4R)
The concentration of is regulated by an electrode (28) placed inside the seventh grid (G7).

Therefore, when the electron gun (22) is configured as described above, the electrons emitted from the cathode (K) form a crossover between the first and second grids (Gl) and (G2), and The electron beam (4B), (4G), (4
R) and enters the third grid (G3) while diverging. This electron beam (4B), (4G), (4
R) then the third, fourth and fifth grids (G3),
(G4), (G5), a unipotential type parallel plate lens (first lens) Ll, and further the fifth, sixth, and seventh grids (G5) (G13), (
07), and then receives the action of the unipotential quadrupole lens (second lens) L2 formed by the seventh
, the eighth grid (G7), and (08) are focused and concentrated onto the phosphor screen (6) by a large-diameter lens (third lens) L3.

The focusing and concentration effect of the electron gun (22) is shown in FIG. 7 using an equivalent optical model. The electron beam (4
B), (4G), (4R) are not deflected, the vertical direction is coaxial) as shown in the figure, the cathode (K
) is emitted from the electron beam (
4B), (4G), and (4R) are the dynamic voltages VD applied to the fourth grid (G4) constituting the parallel plate lens L1 and the sixth grid (G6) constituting the quadrupole lens L2 (see Fig. 6). ) weakens the strength of the parallel plate lens LL and the quadrupole lens L2, so that the light enters the large-diameter lens L3 on a trajectory that is not much different from the trajectory when entering the third grid (G3), and this large-diameter lens L3 causes focused on a phosphor screen (B) and a pair of side beams (4B), (4
R) is subjected to a concentration effect and a good beam spot can be obtained.

On the other hand, the electron beam (4B) is
, (4G), and (4R), in the vertical direction, as shown in FIG.
) and the sixth grid (G
6) The intensity of the parallel plate lens L1 and the quadrupole lens L2 is strengthened by the dynamic voltage VD applied to the electron beams (4B) and (4G), which are weakly focused by the brifocus lens P1 and enter the third grid (G3).
, (4R) is once focused by the parallel plate lens L1, then diverged by the quadrupole lens L2, and enters the large-diameter lens L3. Therefore, the virtual object point position by this large-diameter lens L3 moves toward the phosphor screen (6) side, and is focused only by the central part of the lens, which has a relatively weak concentration, so that the electron beam (4B)
, (4G), and (4R) are more underfocused than when not deflecting. However, in reality the deflection device (
Due to 5), the force in the overfocus direction is received.
On the phosphor screen (6) an optimally focused and good beam spot is obtained. Furthermore, in the case of this deflection, the vertical diameters of the electron beams (4B), (4G), and (4R) within the deflection magnetic field are smaller than in the case of no deflection, so even if the amount of deflection increases, the electron beam (4B).

The deflection aberration experienced by (4G) and (4R) becomes smaller.

Therefore, even when deflecting at a fairly large deflection angle,
Optimally focused on the phosphor screen (6), a good beam spot is obtained.

On the other hand, in the horizontal direction, the electron beam (4B).

When (4G) and (4R) are not deflected, the electron beam (4B
>.

(4G) and (4R) are the fourth grid constituting the parallel plate lens L1 and the sixth grid constituting the quadrupole lens L2.
The dynamic voltage VB applied to the grid significantly weakens the strength of the parallel plate lens Ll and the quadrupole lens L2, thereby causing the large-diameter lens L3 to enter the third grid (G3) on almost the same trajectory as it enters the third grid (G3). incident.

Also, electron beam (4B), <4G), (4R
), as shown in FIG. strength is weakened,
On the other hand, the intensity of the quadrupole lens L2 is slightly strengthened, so that the electron beam (4B) is weakly focused by the prefocus lens P1 and enters the third grid (G3).
(4G) and (4R) enter the quadrupole lens L2 without being affected by the parallel plate lens Ll,
This quadrupole lens L2 focuses the large-diameter lens L.
3. In this case, the electron beam (4B), (
4G), (4R) are focused near the center of the large-diameter lens L3, where the focusing power is relatively weak, and the virtual object point in the large-diameter lens L3 becomes the electron beam (4B), (4R).
G), (4R) than when not deflecting the cathode (
K) side, resulting in slightly overfocus compared to the case without deflection.

However, electron beams (4B), (4G), (4
R) is subjected to a force in the direction of underfocus to some extent by the deflection magnetic field, so that a good beam spot with slightly overfocus is obtained on the phosphor screen (6) from the optimum focusing.

Therefore, if the electron gun (22) is configured as described above, three electron beams (4B), (4G), (4R)
Even when deflecting at a fairly large deflection angle, a good beam spot can be obtained and the entire screen can be brought into optimal focus.

In the above embodiment, voltages synchronized with the deflection of the electron beam were applied to the fourth and sixth grids separately, but since the fourth and sixth grids can also be used at the same potential, the dynamic voltage can be applied with one terminal.

In addition, the waveform of the dynamic voltage applied to the fourth and sixth grids is such that the polarity of the quadrupole lens constituted by the fifth, sixth, and seventh grids is reversed, as shown by the curve (31) in Figure 8. As shown, it may be a parabolic waveform that rises as the amount of deflection increases.

[Effect of the invention] The main lens of the electron gun that focuses the electron beam is divided into a first lens that strengthens the focusing power in the vertical direction as the amount of deflection of the electron beam increases, and a first lens that increases the focusing power in the vertical direction as the amount of deflection of the electron beam increases. By using at least three electron lenses including a second lens that diverges the electron beam, the electron beam can be properly focused on the phosphor screen regardless of whether or not the electron beam is deflected, and the electron beam can be focused on the phosphor screen without deflecting the deflection magnetic field. When passing through the beam, its vertical diameter can be reduced as the amount of deflection increases, thereby reducing deflection aberrations and improving the beam spot shape at the periphery of the screen even when deflecting at a fairly large deflection angle. Therefore, a color picture tube device with good image performance can be obtained.

[Brief explanation of drawings]

Figures 1 to 8 are detailed explanatory diagrams of this invention.
The figure is a cross-sectional view showing the main part configuration of a color picture tube device, which is one embodiment of the system, and FIG.
Figure 3 shows the shape of the electron beam passing hole on the grid side. Figure 3 also shows the shape of the electron beam passing hole on the fourth grid side of the third grid, the fourth grid, the fifth grid, and the sixth grid side of the seventh grid. , Figure 4 is also the same as Figure 6.
A diagram showing the shape of the electron beam passing hole in the grid, FIG. 5 is a diagram showing the shape of the electron beam passing hole in the electrode provided inside the seventh grid, and FIG. 6 is a diagram showing the shape of the electron beam passing hole in the electrode provided inside the seventh grid. Dynamic voltage waveform diagram, Figure 7 (a
) to d) are equivalent optical model diagrams for explaining the action of the electron gun, respectively, FIG. 8 is a waveform diagram of different dynamic voltages applied to the fourth and sixth grids, and FIG.
The figure shows the configuration of a conventional color picture tube device. Figures 1.theta. (a) and (b) are diagrams for explaining the influence of the deflection magnetic field of the conventional color picture tube device on the beam spot, respectively. The figure shows the distortion of the beam spot on the screen, and Figures 12(a) and 12(b) show the areas where the dynamic focus effect is small on the phosphor screen with aspect ratios of 4=3 and IB=9, respectively. FIG. 4B, 4R...Pair of side beams 4G...Center beam 5...Deflection device 6...
Phosphor screen 22...electron gun

Claims (1)

[Scope of Claims] An electron gun includes a cathode, a plurality of grids that control electron emission from the cathode to form an electron beam, and a plurality of grids constituting a main lens that focuses the electron beam. In a color picture tube device that scans the phosphor screen horizontally and vertically by deflecting the electron beam emitted from the electron gun by a deflection magnetic field formed by a deflection device, the main lens of the electron gun is configured to deflect the electron beam. Consisting of at least three electron lenses, including a first lens that strengthens the focusing power in the vertical direction as the amount of deflection increases, and a second lens that diverges the electron beam in the vertical direction as the amount of deflection increases. A color picture tube device characterized by: