JP2825264B2 - Color picture tube equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a three-electron beam type color picture tube device.

(Prior Art) Generally, a color picture tube is mainly called a three-electron gun system. Among them, an in-line type electron gun in which three electron guns are arranged in a line is used, the horizontal deflection magnetic field is set to a pincushion shape as shown in FIG.
The three electron beams are self-concentrated (self-convergence) by using asymmetric magnetic fields each distorted in a barrel shape as shown in FIG. Since such a self-concentrated color picture tube can reduce power consumption,
It greatly contributes to improving the quality and performance of color picture tubes, and is currently the mainstream color picture tubes.

On the other hand, the inhomogeneity of the deflecting magnetic field as described above has a disadvantage that the resolution at the peripheral portion of the screen of the color picture tube is reduced. That is, the cross-sectional shape of the electron beam is distorted in accordance with the deflection angle of the electron beam, and as shown in FIG. The spot (5) has a shape including a low-luminance halo section (7) that is long in the vertical direction in addition to an elliptical high-luminance core section (6) that is long in the horizontal direction, and the resolution around the screen is significantly reduced.

The distortion of the electron beam spot as described above is caused by the fact that the deflection yoke in the self-concentration method gives an asymmetric magnetic field to three electron beams as shown in FIGS. 7 (a) and 7 (b). This is because the electron beam in the magnetic field is less concentrated in the horizontal direction and conversely stronger in the vertical direction.

Such reduction in resolution due to deflection distortion can be reduced by reducing the diameter of the electron beam passing through the main lens and the deflection magnetic field. For this purpose, generally, a method of strongly narrowing the electron beam with a prefocus lens is used. However, in this case, there is a disadvantage that the crossover diameter increases and the electron beam spot diameter at the center of the screen increases.

Alternatively, deflection distortion can also be reduced by making the prefocus lens an asymmetric lens and setting the vertical direction of the electron beam in an underfocus state at the center of the screen.

In this case, the electron beam spot at the center of the screen generally has an elliptical shape having a major axis in the vertical direction, and the resolution of the center of the screen is also reduced.

Alternatively, the diameter of the electron beam spot at the periphery of the screen can be improved by a method of changing the intensity of the electron lens in synchronization with the deflection, that is, a so-called dynamic focus method.

Such a dynamic focus method includes a method in which a divergence angle of a vertical electron beam is dynamically changed in a prefocus lens or a sub lens, and a method in which a vertical focusing power of a main lens is dynamically changed. In either case, the vertical diameter of the electron beam in the deflecting magnetic field is larger at the time of deflection at the periphery of the screen than at the time of deflection at the center of the screen. As a result, there is a disadvantage that the effect of improving the beam spot diameter is reduced.

Since the deflection aberration of the electron beam is greater due to the horizontal deflection magnetic field than the vertical deflection magnetic field, such a drawback becomes a problem especially when scanning at a wide deflection angle of a horizontally long screen such as a high definition television, The beam spot diameter is deteriorated at the outermost part in the horizontal direction of the screen and at the outermost part of the screen diagonally, and the resolution is reduced.

As described above, the region where the effect of the dynamic focus is small is slightly different depending on the method, dimensions, and the like of the electron gun and the deflection yoke. However, there is a problem when the horizontal deflection angle is about 90 ° or more. This is shown in FIG.
12 As shown in Figure (b), the screen aspect ratio is 4: 3, 100
゜ About 10% of the whole screen in the case of deflection (shaded area in FIG. 12 (a)), aspect ratio 16: 9, 110 ゜ About 20% of the whole screen in the case of deflection (FIG. 12 (b) (Hatched area).

Therefore, this is a problem particularly when the aspect ratio is 16: 9, and becomes a serious problem in a high-definition television CRT requiring a high resolution up to the periphery of the screen.

(Problems to be Solved by the Invention) As described above, the conventional technique has a problem that the beam spot diameter is deteriorated at the outermost position in the horizontal direction and the outermost position in the diagonal direction of the screen at the time of wide-angle deflection.

An object of the present invention is to provide a color picture tube device having a high resolution from the center of the screen to the outermost part of the screen even when the deflection angle is large or in a horizontally long screen such as a high-definition television.

[Configuration of the invention]

(Means for Solving the Problems) The electron gun section of the color picture tube device according to the present invention has at least first and second two electron lenses, and is used in a first deflection area having a small deflection amount. Corrects the beam spot distortion due to the deflecting magnetic field by changing the strength of the second electron lens, and changes the strength of the first electron lens in the second deflecting area where the deflection amount is large, thereby changing the beam spot due to the deflecting magnetic field. This is to correct the distortion.

Particularly, in a region where the deflection amount is large, the beam spot diameter in the deflection magnetic field is reduced so that even when the deflection amount is large, the deflection aberration can be reduced.
A good beam spot is obtained.

(Operation) The vertical focusing state of the electron beam by the electron gun of the color picture tube device of the present invention is shown by an equivalent optical model in FIGS. 2, 3 and 4. 2 shows a case where the electron beam is not deflected, FIG. 3 shows a case where the deflection amount is small, and FIG. 4 shows a case where the deflection amount is large.

In the case where the electron beam is not deflected, the electron beam generated at the cathode K as shown in FIG.
After the PL, the first lens L ₁ , and the second lens L ₂ are also focused to some extent, they are focused by the third lens L ₃ to form a just focus on the screen.

In the case the amount of deflection is small, the second lens L ₂ is weakened as shown in Figure 3. Therefore, the electron beam generated by the cathode K is focused by the pre-focus lens PL, a third lens L ₃ is hardly focused in the second lens L ₂ after being focused by the first lens L _1. For this reason, if there is no deflecting magnetic field, underfocusing occurs on the screen, but the deflecting magnetic field receives a force in the overfocus direction to achieve just focus.

When the amount of deflection is large, the first lens is strengthened and the second lens remains weak as shown in FIG.
Therefore, after the electron beam generated at the cathode K, which is focused by the pre-focus lens PL, which focuses largely by the first lens L _1, the cross-over point between the first lens L ₁ and the third lens L ₃ Is generated.

The second lens L ₂ most electron beam is converged by the third lens L ₃ without being focused. Therefore, the third lens L ₃
The position of the virtual object point is largely moved to the screen side, so that there is no defocus on the screen when there is no deflection magnetic field. Actually, just-focus is obtained by receiving a force in the overfocus direction by the deflection magnetic field. Further, in this case, the vertical diameter D ₃ of the electron beam in the deflection magnetic field, it becomes significantly smaller than the diameter in the case of not deflected (Fig. 2 D _1), the electron beam is subjected in the case deflection amount is large Deflection aberrations are reduced, and just-focusing can be easily performed on the screen even at a considerably large deflection angle.

Regarding the focusing of the electron beam in the horizontal direction, since the deterioration of the spot diameter due to the deflection magnetic field is small, the focusing state of the electron beam does not change even if the intensity of the first lens L ₁ and the second lens L ₂ is changed. I have to do it. For this reason, the first lens L ₁ and the second lens L ₂ are lenses acting only in the vertical direction, for example, with the electrodes in the state shown in FIG. 10 facing each other.

(Embodiment) FIG. 1 is a cross-sectional view of a part of a screen portion taken along the XZ plane near a neck portion of a color picture tube device embodying the present invention.

In FIG. 1, an electron gun portion (100) arranged in a neck (5) includes a cathode (cathode) K, a first grid G ₁ ,
Second grid G ₂ , third grid G ₃ , fourth grid G ₄ , fifth
A grid G ₅ , a sixth grid G ₆ , a seventh grid G ₇ , an eighth grid G ₈ , an insulating support BG supporting these grids and a valve spacer (112), and the electron gun (100) has a stem pin ( 113).

The cathode K is has a respective internal heaters, three electron beams B _R, B _G, generates the B _B.

The first grid G ₁ and the second grid G ₂ have three relatively small beam passage holes corresponding to the three cathodes K, and control and accelerate the electron beam from the cathode K in these portions. , A so-called electron beam forming unit GE.
Next, the third grid G ₃ (the side facing G ₂ ) is also 3
There are three relatively large circular beam passage holes as shown in FIG.

The fourth grid side electrode of the third grid G _3, fourth grid G _4, the fifth grid G _5, sixth grid G _6, and 7
Beam through holes of the sixth grid side electrode of the grid G ₇ is 10
As shown in the figure, the shape is such that the horizontal hole diameter is about 5 times or more the vertical hole diameter in common to the three electron beams. Therefore the third grid G _3, fourth grid G _4, unipotential lenses formed from the fifth grid G _5, and the fifth grid G _5, sixth grid G _6, Uni formed of seventh grid G ₇ The potential lens has almost no lens action in the horizontal direction and has a focusing action only in the vertical direction, that is, a so-called parallel plate lens.

Concentration of three electron beams are closer to the eighth grid G ₈ side of the middle of the seventh grid G _7, as the correction means of Focusing, electrodes having three non-circular circular opening as shown in FIG. 11 (G ₇ D).

The eighth grid G ₈ partially overlaps the seventh grid G _7, a substantially cylindrical electrode which includes a seventh grid G ₇ is cylindrical electrodes, large circular beam through holes of the seventh grid G ₇ (G ₇ T) to form a substantially large-diameter circular lens.

The outer periphery of the tip end of the eighth grid G _8, valve spacer (112) to have a, in contact with the funnel (4) neck from the inner wall (5) conductive film that is applied to the inner wall (10), the funnel An anode high voltage is supplied from the provided anode terminal. The distal end of the eighth grid G _8, can be placed a magnetic field modifying element with respect to the magnetic field by the deflection yoke. More cathodes K, first from the grid G ₁ 8
It is fixedly supported by insulating support BG to grid G _8.

A deflection yoke (7) is attached from the neck (5) to the funnel (4).
Of electron beams B _R, B _G, and B _B horizontally, consisting of a horizontal deflection coil and a vertical deflection coil for deflecting vertically. Further, a multipole magnet (51) for adjusting the trajectory of the beam is provided.

In the above electrode configuration, for example, the cathode K is about 15
The cutoff voltage is 0 V, and the video signal is added to the cutoff voltage.
Grid G ₁ is the ground potential, the second grid G ₂ is 500V~1K
V, the third grid G ₃ are 5 to 10 kV, the fourth grid G ₄ are 2-10
KV, the fifth grid G ₅ is 5 to 10 kV, the sixth grid G ₆ 3 to 10
KV, the seventh grid G ₇ 5 to 10 kV, the eighth grid G ₈ applies a 25~35KV anode high voltage.

Further, voltages that change in synchronization with the deflection as shown in FIGS. 5 and 6 are applied to the fourth grid G ₄ and the sixth grid G ₆ , respectively.

That is, the voltage V _D2 applied to the fourth grid G ₄ shown in FIG. 5 is a substantially constant voltage of 5 to 10 KV when the horizontal deflection angle is about 90 ° or less and the deflection amount is relatively small, 1 when the horizontal deflection angle is about 90 ° or more and the deflection amount is relatively large.
The voltage is reduced by about 5 KV. The voltage V _D1 applied to the sixth grid G ₆ shown in FIG.
When the deflection amount of 0 ° or less is small, the parabolic shape increases between about 3 to 10 KV according to the increase of the deflection amount, and when the horizontal deflection angle is about 90 ° or more, the parabolic shape increases.
It becomes a constant voltage of 10KV.

With such a potential configuration, the beams generated from the respective cathodes form a first crossover by the first grid G ₁ and the second grid G _{2 and} are formed by the second grid G ₂ and the third grid G ₃ . go incident on third grid G ₃ is focused by the pre-focus lens.

The third grid G _3, fourth grid G _4, the fifth grid G ₅ unipotential lenses formed from (referred to as the first parallel plate lens) and the fifth grid G _5, sixth grid G _6, 7
For unipotential lenses formed from grid G ₇ (referred to as a second parallel plate lens) is a lens that acts only in the vertical direction as described above, in the horizontal direction of the beam without being affected by these lenses By the large-diameter lens formed by the sixth grid G ₆ and the seventh grid G ₇ , the beams on both sides are focused and concentrated on the screen under the focusing action.

Next, the vertical focusing of the beam will be described. When no deflection occurs, the first parallel plate lens exhibits a weak focusing effect, and the second parallel plate lens exhibits a strong focusing effect.

Accordingly beam incident on third grid G ₃ are seventh grid after being focused respectively in the first, second parallel plate lens
G _7, according to the eighth grid G ₈ is focused by a large diameter lens to just focus on the screen.

In a region where the horizontal deflection angle is about 90 ° or less and the deflection amount is relatively small, the sixth grid potential becomes high and the potential difference between the fifth and seventh grid potentials becomes small, so that the second parallel flat lens is weakened, The divergence angle of the beam incident on the aperture lens increases, and changes in the underfocus direction as compared with the case without deflection. Since this electron beam receives a force in the overfocus direction due to the deflection magnetic field, the electron beam is just focused on the screen.

In a region where the horizontal deflection angle is about 90 ° or more and the amount of deflection is relatively large, the fourth grid potential becomes low, so that the first parallel plate lens is strengthened, and the distance between the first parallel plate lens and the large aperture lens is increased. A second crossover is formed, diverges again, and enters the large-diameter lens. Therefore, the beam largely changes in the underfocus direction as compared with the case where there is no deflection. Since this electron beam changes in the overfocus direction due to the deflection magnetic field, it becomes just focus on the screen. However, the diameter in the vertical direction of the beam in the deflecting magnetic field is much smaller than in the case without deflection,
The amount of deflection aberration experienced by the beam is also reduced and good focusing is achieved even at fairly large deflection angles.

〔The invention's effect〕

As described above, according to the color picture tube device of the present invention, it is possible to obtain a good beam spot over the entire screen even with a considerably large deflection angle, and to obtain a color picture tube device with improved image performance. it can.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part of a color picture tube apparatus embodying the present invention, FIGS. 2 to 4 are optical equivalent views of a YZ cross section of an electron gun, and FIGS. FIGS. 7 and 8 are schematic diagrams showing beam distortion due to deflection aberration, FIGS. 9 to 11 are front views of electrodes showing electrode shapes in the embodiment, and FIGS. a) and FIG. 12 (b)
FIG. 3 is a schematic diagram of a screen for explaining a dynamic focus effect.

Continuation of the front page (72) Inventor Jiro Shimokawabe 1-9-2 Hara-cho, Fukaya-shi, Saitama Prefecture Inside the Toshiba Fukaya CRT plant (56) References ) Surveyed field (Int. Cl. ⁶ , DB name) H01J 29/48-29/51

Claims (1)

(57) [Claims] 1. A color picture tube device comprising an electron gun section, a deflecting section, and a screen section, wherein a deflection section scans an electron beam emitted from the electron gun section in a vertical direction and a horizontal direction. Is an electron beam forming unit that includes a cathode that generates, accelerates, and controls the electron beam, and focuses this electron beam.
A main electron lens portion for focusing; the main electron lens portion has a first electron lens, a second electron lens, and a large-diameter lens from a side close to the cathode; A first deflection area and a second deflection area having a large deflection amount, wherein the lens strength of the first electron lens changes in accordance with the deflection amount of the second deflection area; A color picture tube apparatus, wherein a crossover is formed between the first and second electron lenses, and a lens strength of the second electron lens changes according to a deflection amount of the first deflection area.