JP2563273B2 - Picture tube device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a picture tube device configured to obtain high resolution over the entire area of a phosphor screen surface.

2. Description of the Related Art The resolution characteristics of a picture tube device largely depend on the size and shape of the beam spot. That is, unless the beam spot, which is a bright spot generated on the phosphor screen surface by the electron beam bombardment, has a small diameter and is close to a perfect circle, high resolution cannot be obtained.

However, since the electron beam trajectory from the electron gun to the phosphor screen surface becomes longer as the deflection angle of the electron beam increases, a small diameter and perfect circular beam spot can be obtained at the center of the phosphor screen surface. If the optimum focus voltage is maintained, the peripheral portion of the phosphor screen surface becomes overfocused, and a good beam spot and resolution cannot be obtained in the peripheral portion.

Therefore, a so-called dynamic focus system is adopted in which the focus voltage is increased and the electric field of the main lens is weakened as the deflection angle of the electron beam is increased. The so-called dynamic focus system is used to drive an in-line type color picture tube as described below. Not suitable for. That is, in an in-line type color picture tube in which three electron beam emitting parts are arranged in a straight line, the horizontal deflection magnetic field distribution is pincushion-shaped and the vertical deflection magnetic field distribution is barrel-shaped in order to obtain a self-convergence effect. Since they are respectively distorted, the cross-sectional shape of the electron beam passing therethrough is distorted into a non-circular shape, and the beam spot generated especially in the peripheral portion of the phosphor screen surface is also distorted into a non-circular shape. Since the phosphor screen surface is usually in the shape of a horizontally long rectangle, the distortion in the peripheral portion in the horizontal direction becomes particularly large.

As shown in FIG. 5, 3
The electron beams 1, 2, 3 of the book are deflected in the direction shown by the arrow 5 by being incident on the horizontal deflection magnetic field 4 having a pincushion distribution. That is, the horizontal deflection magnetic field 4 having a pincushion-like distribution is composed of a dipole magnetic field component 6 as shown in FIG. 6 (a) and a quadrupole magnetic field component 7 as shown in FIG. 6 (b). It can be considered that the bipolar magnetic field component 6 gives the electron beam 9 a deflection action in the direction indicated by the arrow 8. The quadrupole magnetic field component 7 gives a self-convergence action to the three electron beams. Looking at one electron beam 9, a divergence action is given in the horizontal direction and a focusing action is given in the vertical direction. Therefore, the cross-sectional shape has a horizontally long flat shape.

By the way, since the diverging action acts in a direction to cancel the overfocus of the beam spot due to the lengthening of the electron beam trajectory as the beam deflection angle increases, in the in-line color picture tube, the horizontal direction of the beam spot is , The optimum focus state is maintained during the deflection period. However, in the vertical direction, the degree of overfocus is significantly increased by the addition of the focusing effect. As a result, the beam spot generated in the central portion of the phosphor screen surface has a circular shape as shown in FIG. 7A, while the beam spot generated in the horizontal peripheral portion is shown in FIG. As shown in (b), the high brightness core part
Distortion into a non-circular shape consisting of 10 and haze portion 11 in the low-brightness portion, and particularly a large vertical extension of haze portion 11 adversely affects the focus characteristics.

If the conventional dynamic focus method is applied in such a case, this method weakens the lens action of the main lens evenly regardless of the horizontal and vertical directions.
Even if the haze portion 11 can be removed in the vertical direction, the horizontal direction, which is already in the optimum focus, becomes an underfocus state, and the horizontal diameter increases. As a result, the beam spot becomes remarkably long and horizontal resolution is reduced. Japanese Patent Application Laid-Open No. 61-99249 discloses a picture tube device capable of solving such problems and obtaining high resolution over the entire phosphor screen surface. In this case, at least the accelerating electrode, the first focusing electrode and the second focusing electrode are sequentially arranged between the control electrode and the final accelerating electrode, and the vertically elongated electron beam is formed on the end face of the first focusing electrode on the second focusing electrode side. Through the through hole and the first of the second focusing electrodes
An in-line type color picture tube is provided which has laterally long electron beam passage holes on the end surface on the side of the focusing electrode. Then, a constant first focus voltage is applied to the first focusing electrode, a constant high voltage is applied to the final accelerating electrode, and a value higher than the first focus voltage is applied to the second focusing electrode as the deflection angle of the electron beam increases. Voltage applying means for applying the respective dynamic voltages.

According to this structure, at the time when the horizontal deflection becomes zero, that is, when both the first and second focusing electrodes have the same potential, even if the electron beam passage holes of both electrodes are vertically long or horizontally long, these shapes Has almost no effect on the electron beam. Then, a potential difference is generated between the second focusing electrode and the final accelerating electrode, three main lenses are generated there, and the three electron beams are focused to the optimum focus at the central portion of the phosphor screen surface. As the horizontal deflection angle increases, the potential of the second focusing electrode becomes higher than that of the first focusing electrode, and a quadrupole lens electric field is generated between the two electrodes by the vertically long electron beam passage hole and the horizontally long electron beam passage hole. To be done.
Moreover, since the potential difference between the second focusing electrode and the final accelerating electrode is reduced, the lens action of the main lens is weakened.

FIGS. 8 and 9 are for explaining the influence of the electric field of the quadrupole lens on the electron beam, and FIG. 8 shows one vertical electron beam passage hole for the sake of simplicity. A case is shown in which a plate electrode 13 having 12 and a plate electrode 15 having one laterally long electron beam passage hole 14 are arranged so as to face each other and a potential of V ₁ or V ₂ is applied to each. The quadrupole lens electric field generated between both electrodes under the voltage condition of V ₁ <V ₂ has a positive potential on the upper and lower sides with respect to the central portion and has a negative potential on the left and right sides as shown in FIG. Therefore, the lines of electric force are generated in the direction indicated by the arrow 16, and the electron beam 17 receives the attractive force and the repulsive force in the direction indicated by the arrow 18 to have a vertically long cross-sectional shape.
This is contrary to the case where the electron beam passing through the deflection magnetic field has a horizontally long cross-sectional shape due to the quadrupole magnetic field component shown in FIG. 6 (b), and the cancellation of the two prevents the horizontally flattening of the electron beam. be able to.

Further, as the deflection angle increases, the focusing action in the main lens becomes weaker as described above, so that overfocusing due to deflection of the beam spot can be prevented at the same time.
It is possible to reduce the diameter of the peripheral portion of the phosphor screen surface and generate a beam spot close to a perfect circle.

Problems to be Solved by the Invention However, in the picture tube device configured as described above,
Since the first focusing electrode has a vertically long electron beam passage hole and the second focusing electrode has a horizontally long electron beam passage hole, the electron beam passage holes of both focusing electrodes have a circular cross section of the electron gun assembly jig. Even if a metal rod for axis alignment is inserted, accurate axis alignment cannot be achieved, and therefore it becomes very difficult to assemble both focusing electrodes in predetermined relational positions without axis misalignment, which is not suitable for mass production. It was If an axis shift occurs between the two focusing electrodes, the electric field of the quadrupole lens is distorted, and the intended purpose cannot be achieved satisfactorily.

In the picture tube device of the present invention, at least an accelerating electrode, a first focusing electrode and a second focusing electrode are sequentially arranged between a control electrode and a final accelerating electrode, and the first focusing electrode is provided. The end face of the electrode on the side of the second focusing electrode has three square electron beam passage holes, and vertical wing portions for generating an electric field protruding from a region sandwiching the electron beam passage holes from the horizontal direction, and An in-line type having three square electron beam passage holes on the end face of the focusing electrode on the side of the first focusing electrode, and a horizontal blade for electric field generation protruding from a region narrowing the electron beam passage holes from the vertical direction. A color cathode ray tube, a deflection yoke attached to the in-line type color cathode ray tube to distort a horizontal deflection magnetic field into a pincushion shape and a vertical deflection magnetic field into a barrel shape, respectively, and a fixed focus on the first focusing electrode. Voltage applying means for applying a constant high voltage to the final accelerating electrode and a dynamic voltage changing to a value higher than the focus voltage as the deflection angle of the electron beam increases to the second focusing electrode. It is equipped with and.

Action With this configuration, the quadrupole lens electric field is generated by the vertical wing and the horizontal wing, and the electron beam passage hole formed in the end faces of the first and second focusing electrodes facing each other can be formed into a square. Therefore, it is possible to efficiently manufacture an in-line type electron gun without axis misalignment, and to obtain a color picture tube device that exhibits high resolution characteristics over the entire phosphor screen surface.

EXAMPLES Next, the present invention will be described with reference to the examples shown in the drawings.

As shown in FIG. 1, the three cathodes 19, 20, 21 arranged in a horizontal straight line are composed of a control electrode 22, an accelerating electrode 23, a first focusing electrode 24, a second focusing electrode 25 and a final accelerating electrode 26. Together with this, it constitutes an in-line color picture tube electron gun. Then, the first focusing electrode 24 is attached to the end surface on the second focusing electrode 25 side by 3
4 square electric field generating vertical wings 30, 31, 3 which have electron beam passage holes 27, 28, 29 each having a square shape and which protrude from a region sandwiching the electron beam passage hole from the horizontal direction and which are parallel to each other.
It has 2,33. The second focusing electrode 25 has three square electron beam passage holes 34, 3 on the end face on the first focusing electrode 24 side.
5, 36, and two parallel electric field generating horizontal wings 37, 38 projecting from the region sandwiching the electron beam passage hole from the vertical direction, and 3 on the end surface on the final acceleration electrode 26 side.
It has circular electron beam passage holes 39, 40 and 41. Then, on the end surface of the final acceleration electrode 26 on the second focusing electrode 25 side,
Three circular electron beam passage holes 42, 43 and 44 are formed so that three main lenses are formed between the second focusing electrode 25 and the final accelerating electrode 26.

The control electrode 22 and the accelerating electrode 23 have three electron beam passage holes 45, 46, 47, 48, 49 and 50, respectively, and three electron beam passing holes 45 are provided on the end surface of the first focusing electrode 24 on the accelerating electrode 23 side. Circular electron beam passage holes 51, 52, 53 are formed. Further, in FIG. 1, the first focusing electrode 24 and the second focusing electrode 25 are depicted in a considerably separated manner for ease of illustration, but in reality,
As shown in FIG. 3 and the view of FIG. 3 and the III-III cross section thereof, they are assembled in the related positions close to each other.

Typical DC potentials applied to each electrode during operation are cathode: 50 to 150 V, control electrode: OV, acceleration electrode: 300 to 5
00V, 1st focusing electrode …… 6KV (Vfc), final accelerating electrode …… 2
The dynamic voltage of 5 KV (Va) is applied to the second focusing electrode as shown in FIG. 1, which changes in synchronization with the horizontal deflection of the electron beam. The peak value of this voltage waveform is Vf
c + about 500V is suitable. The interval between the two time points showing the peak value corresponds to one horizontal period 1H, and the first and second focusing electrodes
At the time when both 24 and 25 become Vfc, that is, when the horizontal deflection becomes zero, the vertical wings 30 to 33 and the horizontal wings 3 of both electrodes are
7,38 has almost no effect on the electron beam. Then, between the second focusing electrode 25 and the final acceleration electrode 26, Va-Vfc
Potential difference occurs, three main lenses are generated here,
The three electron beams are focused to the optimum focus at the center of the phosphor screen surface.

As the horizontal deflection angle of the electron beam increases, the potential of the second focusing electrode 25 becomes higher than the potential Vfc of the first focusing electrode 24. A quadrupole lens electric field as shown in FIG. 4 is generated in the space surrounded by the horizontal wings 37 and 38 of the focusing electrode 25, and the potential difference between the second focusing electrode 25 and the final acceleration electrode 26 is reduced. Then, the beam focusing effect of the main lens becomes weak.

FIG. 4 shows one central electron beam for the sake of simplicity. Since the horizontal wings 37 and 38 have a higher potential than the vertical wings 31 and 32, the electric lines of force of the quadrupole lens electric field are generated in the direction indicated by the arrow 54, and the electron beam 55 is generated by the arrow.
It receives an attractive force and a repulsive force in the direction indicated by 56 and becomes a vertically long sectional shape. This is because the electron beam passing through the deflection magnetic field is the sixth
Contrary to the distortion of the laterally long cross-sectional shape due to the quadrupole magnetic field component shown in (b) of the figure, the lateral oblong flattening of the electron beam is prevented by the cancellation of both. Further, as the deflection angle increases, the beam focusing action in the main lens becomes weaker as described above, so that the degree of overfocus of the electron beam with the increased deflection angle on the phosphor screen surface is reduced, and the phosphor It is possible to reduce the diameter not only in the central portion of the screen surface but also in the peripheral portion and to generate a beam spot close to a perfect circle. Also, the first and second focusing electrodes 2
Since the electron beam passage holes on the opposite end faces of 4,25 are made square, a metal rod for axial alignment having a circular cross section of the jig is used for the electron beam passage holes of both focusing electrodes 24, 25 when assembling the electron gun. It is possible to insert it and perform accurate axis alignment. Further, in the above-mentioned embodiment, the dynamic voltage synchronized only with the horizontal deflection is applied to the second focusing electrode, but if a more complete improvement is desired, the dynamic voltage synchronized with the vertical deflection is superimposed on the second focusing electrode. It can be applied to the electrodes.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to obtain not only a color picture tube device exhibiting high resolution characteristics over the entire area of the phosphor screen surface, but also especially the end surfaces of the first and second focusing electrodes facing each other. Since a square electron beam passage hole can be formed in each of them, the focusing electrodes can be accurately and easily aligned to assemble an in-line type electron gun, which greatly contributes to improvement in manufacturing yield and quality. The effect is great. Moreover, according to the present invention, by making the electron beam passage hole square, the quadrupole lens electric field generated by the electric field generating vertical / horizontal wings sufficiently penetrates into the corner portion of the electron beam passage hole. , The electron beam shape can be corrected efficiently. Therefore,
The shape of the vertical / horizontal blades for generating an electric field, particularly the length in the axial direction of the picture tube, can be shortened, the distance between the first and second focusing electrodes can be increased, and the second focusing electrode It is possible to widen the design latitude of the picture tube and its electron gun such that the dynamic voltage to be applied can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of an electron gun of a picture tube device embodying the present invention, FIG. 2 is a side sectional view of a quadrupole lens electric field generating portion of the electron gun, and FIG. 3 is a III-III sectional view of FIG. 4 and 5 are sectional views showing the relationship between the quadrupole lens electric field and the electron beam, FIG. 5 is a view showing the relationship between the horizontal deflection magnetic field of the pincushion distribution and the electron beam, and FIG. 6 is the horizontal deflection magnetic field. FIG. 7 is a diagram showing the relationship between the two components and the electron beam, FIG. 7 is a diagram showing the shapes of beam spots formed in the central portion and the peripheral portion in the horizontal direction of the phosphor screen surface, and FIGS. 8 and 9 are quadrupoles. It is a figure for demonstrating the influence which a lens electric field gives to an electron beam. 22 ... Control electrode, 23 ... Accelerating electrode, 24 ... First focusing electrode, 25 ... Second focusing electrode, 26 ... Final accelerating electrode, 30 to 33
...... Vertical wings, 37,38 …… Horizontal wings.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Chisato Kurisu 1006 Kadoma, Kadoma City, Matsushita Electronics Industrial Co., Ltd. (56) References JP 61-250933 (JP, A) JP 62-237642 (JP) , A) JP 61-39347 (JP, A) JP 61-99249 (JP, A) JP 54-150962 (JP, A) JP 61-74246 (JP, A) JP 62-237643 (JP, A) JP-A-62-237641 (JP, A) JP-A-58-198832 (JP, A) JP-A-58-192252 (JP, A) JP-B-60-7345 (JP, A) B2)

Claims (1)

(57) [Claims] 1. At least an accelerating electrode, a first focusing electrode and a second focusing electrode are sequentially arranged between a control electrode and a final accelerating electrode, and an end face of the first focusing electrode on the side of the second focusing electrode, An end surface on the side of the first focusing electrode of the second focusing electrode, which has three square electron beam passing holes and vertical wing portions for generating an electric field protruding from a region sandwiching the electron beam passing holes from the horizontal direction. The in-line color picture tube having three square electron beam passage holes and the horizontal wing portions for electric field generation protruding from the region sandwiching the electron beam passage holes from the vertical direction, and the in-line color picture tube. A deflection yoke attached to distort the horizontal deflection magnetic field into a pincushion shape and the vertical deflection magnetic field into a barrel shape,
A dynamic that changes a constant focus voltage to the first focusing electrode, a constant high voltage to the final accelerating electrode, and a higher voltage to the second focusing electrode as the deflection angle of the electron beam increases. A picture tube device, comprising: voltage applying means for applying a voltage, respectively.