JPH0524609B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides an in-line type color picture tube;
The present invention relates to a color picture tube device comprising a drive means for the color picture tube device.

Conventional configuration and its problems In an in-line color picture tube in which three electron beam emitters are arranged horizontally in a straight line, a saddle-type or toroidal-type deflection yoke is used as the beam deflection means. Therefore, the horizontal deflection magnetic field distribution is distorted into a pink tension shape, and the vertical deflection magnetic field distribution is distorted into a parallel shape. In this way, a self-convergence effect can be obtained, so that the configuration of the convergence system can be significantly simplified.

However, on the other hand, as shown in FIG. 1, the bright spots or beam spots 2 that appear particularly in the peripheral area of the phosphor screen surface 1 are distorted into a non-circular shape due to deflection distortion. Resolution decreases. The beam spot 2 consists of a high-brightness core part 3 in the shape of an oblong bar and a low-brightness haze part 4 attached thereto.

This reduction in resolution due to deflection distortion can be alleviated by reducing the diameter of the electron beam that passes through the main lens of the electron gun and the deflection magnetic field, but to do so, the distance between the cathode of the electron gun and the main lens can be reduced. If the distance is narrowed or the beam is simply narrowed down strongly using a prefocus lens, the lens magnification will become excessive, leading to an undesirable result in which the beam spot appearing in the center of the phosphor screen becomes larger in diameter.

As shown in Figure 2, the optimal focus voltage when considering the horizontal diameter of the beam spot remains unchanged at any position on the phosphor screen surface, whereas the optimal focus voltage when considering the vertical diameter of the beam spot The optimum focus voltage in this case becomes higher toward the periphery of the phosphor screen surface (especially in the E and NE directions). Therefore, if the beam spot is driven at the optimum focus voltage (6KV in Figure 2) that takes into account only the horizontal diameter of the beam spot, the beam spot that appears at the periphery of the phosphor screen becomes overfocused in the vertical direction. This results in vertical haze as described above.

Therefore, as shown in Figure 3, if the vertical focus voltage at the center of the phosphor screen is lower than the horizontal optimum focus voltage, the resolution at the center of the phosphor screen will decrease slightly, but It is possible to increase the resolution in the area.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an image of the entire area of the phosphor screen surface without resorting to the above-mentioned compromises, i.e. without sacrificing the resolution in the central part of the phosphor screen surface. An object of the present invention is to provide a color picture tube device that can obtain high resolution.

Structure of the Invention According to the color picture tube device of the present invention, a first electrode for generating a quadrupole lens in the form of a plate having three vertically long electron beam passing holes arranged in parallel in the horizontal direction; A plate-shaped quadrupole lens generating second electrode formed by horizontally arranging three electron beam passing holes is arranged between a plurality of focusing electrodes to which a constant focusing voltage Vfoc is applied. A constant high voltage Va is applied to the final accelerating electrode adjacent to the focusing electrode located at the final stage of the plurality of electrodes, and the voltage applied to at least one of the first and second electrodes is adjusted depending on the deflection angle of the electron beam. This will be explained in detail below with reference to embodiments shown in the drawings.

Description of Examples In FIG. 4, 5 is a control electrode, 6 is an acceleration electrode to which an acceleration voltage of V _g2 is applied, 7 is a first focusing electrode, 8 is a first electrode for generating a quadrupole lens electric field, and 9 is a first electrode. 2 focusing electrodes, 10 a second electrode for generating a quadrupole lens electric field, 11 a third focusing electrode, and 12 a final accelerating electrode to which a high voltage V _a is applied. However, the first, second, and third focusing electrodes 7, 9, and 11 are commonly connected within the tube, and a focusing voltage Vfoc is applied thereto. The quadrupole lens electric field generation first electrode 8 is a plate having three vertically long electric beam passing holes 13, 14, and 15 arranged horizontally in parallel, as shown in the plan view shown in FIG. 5a. A voltage of several hundred volts called _V1 is applied to this. In addition, a second electrode 10 for generating a quadrupole lens electric field
is a plate-shaped one having three horizontally long electron beam passing holes 16, 17, and 18 arranged in parallel in the horizontal direction as shown in the plan view in _FIG . A voltage of several hundred volts is applied.

When V ₁ and V ₂ are maintained at a constant voltage lower than Vfoc, the quadrupole lens electric field generation first electrode 8
Three front-stage four-stage lens electric fields are generated near the three electron beam passing holes 13, 14, and 15, and
Three subsequent quadrupole lens electric fields are generated near the three electron beam passage holes 16, 17, and 18 of the second pole lens electric field generation electrode 10. The four-pole lens electric field is as shown in Figure 6, and the four poles in the previous stage are
The electron beam that has passed through the polar lens electric field is subjected to a focusing effect in the horizontal direction with respect to its cross-sectional shape, and a diverging effect in the vertical direction. Furthermore, the electron beam that has passed through the electric field of the quadrupole lens in the latter stage is subjected to a diverging effect in the horizontal direction with respect to its cross-sectional shape, and is subjected to a converging effect in the vertical direction. Therefore, the lens effects received by the electron beam from both lens electric fields after passing through the front and rear quadrupole lens electric fields are completely canceled out, resulting in an electron beam that passes through a normal axisymmetric multi-stage lens electric field. is equivalent to The conditions for such a countervailing effect are to increase both V ₁ and V ₂ and reduce Vfoc.
It does not change even in the process of approaching . However, since the electric fields of both the front and rear quadrupole lenses become weak, the electron beam reaching the phosphor screen surface is underfocused in the horizontal and vertical directions with respect to its cross-sectional shape. And from this state of underfocus
When V ₁ is lowered, only the electric field of the quadrupole lens in the front stage becomes stronger, and the electron beam that reaches the phosphor screen has a focusing effect in the horizontal direction and a diverging effect in the vertical direction with respect to its cross-sectional shape. This results in optimal focus in the horizontal direction. Furthermore, the degree of underfocus increases in the vertical direction.

On the other hand, in a color picture tube device equipped with an in-line type color picture tube deflection yoke, the degree of convergence of the electron beam in the vertical direction increases as the beam deflection angle increases due to the cross-sectional shape of the electron beam, as described above. If, as the deflection angle increases, only V ₁ is gradually lowered from a few hundred volts similar to V ₂ , the cross-sectional shape of the electron beam reaching the phosphor screen surface can be changed both horizontally and vertically. This allows an optimum focus state to be achieved, and it is possible to obtain a beam spot with a small diameter and close to a perfect circle over the entire area of the phosphor screen surface.

In addition, by appropriately selecting the shape and installation position of the second electrode 10 that contributes to the generation of the quadrupole lens electric field in the latter stage, it is possible to maintain V ₁ at a low voltage and increase the beam deflection angle. Accordingly, the same effect as described above can be obtained by gradually increasing V ₂ from a low voltage or by relatively changing V ₁ and V ₂ .

FIG. 7 shows another embodiment of the present invention. Here, the first and second electrodes 8 and 10 for generating a quadrupole lens electric field are arranged between the first focusing electrode 7 and the second focusing electrode 9, and each of V ₁ and V ₂ is The values are changed in the same way as before.

Effects of the Invention Since the present invention is configured as described above, it is possible to maintain the first and second electrodes at a relatively low voltage of several hundred volts or less, and to maintain the phosphor screen without affecting the main lens. It is possible to generate a beam spot with a small diameter and close to a perfect circle over the entire area of the surface, and particularly when applied to an apparatus that requires a high-definition reproduction screen, excellent effects can be obtained.

[Brief explanation of the drawing]

Figure 1 is a diagram to explain the shape distortion of the beam spot of an in-line color picture tube, Figure 2 is a characteristic diagram showing the relationship between the position of the shape distortion and the optimum focus voltage, and Figure 3 is a diagram for vertical focus. A focus voltage characteristic diagram when deflection distortion is reduced by lowering the voltage below its optimum value. FIG. 4 is a side view of an electron gun of a color picture tube device implementing the present invention.
FIGS. 5a and 5b are plan views of the first and second electrodes for generating the quadrupole lens electric field of the electron gun, FIG. 6 is a diagram showing the quadrupole lens electric field, and FIG. 7 is another embodiment of the present invention. FIG. 2 is a side view of an example electron gun. 7...First focusing electrode, 8...First electrode for generating a quadrupole lens electric field, 9... Second focusing electrode, 10...4
A second electrode for generating a polar lens electric field, 11... a third focusing electrode.

Claims (1)

[Claims] 1 A first electrode for generating a quadrupole lens in the form of a plate with three vertically long electron beam passing holes arranged in parallel in the horizontal direction; A plate-shaped quadrupole lens generating second electrode is arranged between a plurality of focusing electrodes to which a constant focusing voltage Vfoc is applied, and a focusing electrode located at the final stage of the plurality of focusing electrodes is While applying a constant high voltage Va to the adjacent final accelerating electrode,
A color picture tube device characterized in that a voltage applied to at least one of the first and second electrodes is changed in accordance with a change in a deflection angle of an electron beam.