KR20020041484A - Color image receiving tube - Google Patents

Abstract

PURPOSE: A color cathode ray tube is provided to reduce an interval between effective beams on a deflection center in a center part and a peripheral part of screen according to deflection current by using two electron quad poles. CONSTITUTION: A panel(1) has a flat outer face and a curved inner face. An inline electron gun(9) is mounted in a neck(2). A funnel(3) is contacted with the panel(1). A maximum angle of deflection is 110 degrees. A stripe type phosphorus material is formed on a phosphor screen(4). A shadow mask(5) has a plurality of slots. The shadow mask(5) is supported by a support frame(6). The support frame(6) is installed on the panel(1) by using a spring(8). An inner magnetic shield(7) is mounted on the support frame(6). A deflection yoke(10) is adhered to a cone portion(33) of the funnel(3). The deflection yoke(10) is formed with a horizontal deflection coil(101), a separator(102), a vertical deflection coil(103), and a core(104). A magnet(11) is adhered to an upper portion and a lower portion of the horizontal deflection coil(101). A magnet assembly(12) controls convergence and purity of electron beam. A tension band(13) is used for preventing explosion of a bulb. The first electron fourfold pole coil(14) and the second electron fourfold pole coil(15) are installed between the deflection yoke(10) and the magnet assembly(12).

Description

COLOR IMAGE RECEIVING TUBE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to color CRTs, and more particularly to color CRTs which have improved distortion of the screen.

Background Art A color water tube having a flat outer surface has been developed from the viewability of the screen, prevention of external light from shining, and the like. As a means for realizing this, there is a method of giving the curvature to the inner surface of the panel while keeping the outer surface of the panel flat. This method has an advantage that the shadow mask can have a curved surface, thereby utilizing the manufacturing technology of the conventional shadow mask. On the other hand, with respect to the inner surface of the panel, it is necessary to have excessive curvature compared to the outer surface, and as a result, the glass thickness around the panel becomes excessive as compared to the glass thickness in the center of the panel. This causes problems such as a difference in brightness at the center of the fluorescent surface and the surroundings, and the influence of the curved surface on the inner surface of the panel impairs the flatness. Therefore, when the outer surface of the panel is flat, the curvature of the inner surface of the panel should be as small as possible.

On the other hand, the larger the curvature of the shadow mask is, the easier it is to create. As a method for solving this problem, a method of increasing the shadow mask curvature more than the panel inner curvature is proposed by effectively reducing the electron beam distance s dimension from the center of the screen around the screen. As a document describing this technique, a report of International Display Workshop (IDW) '98, pages 412-416.

The document describes the principle of effectively reducing the s dimension in the periphery by using two electron quadrupoles. The above document uses the first and second electron quadruple, but the second electron quadruple close to the fluorescent surface is in a deflection magnetic field. That is, the s dimension greatly changes in the deflection magnetic field. If the s dimension changes significantly in the deflection magnetic field, it becomes difficult to control convergence and color purity (purity).

1 is a cross-sectional view showing an outline of a color CRT tube of the present invention.

Figure 2 is a slot hole arrangement of the shadow mask.

3 is a detailed view defining the dimensions of the panel.

4 is an explanatory diagram of a prior art for effectively changing s dimensions.

5 is an explanatory diagram of the present invention.

6 is an explanatory diagram of a first embodiment of the present invention;

7 is an explanatory diagram of a first embodiment of the present invention;

8 is a detailed view of the main part of the present invention;

Fig. 9 is a detailed view of the electron quadrupole portion in the present invention.

Fig. 10 is a detailed view of the electron quadrupole portion in the present invention.

Fig. 11 is a detailed view of the electron quadrupole portion in the present invention.

12 is an explanatory diagram of a second embodiment of the present invention;

Figure 13 is an explanatory diagram of a second embodiment of the present invention.

14 is an explanatory diagram of a third embodiment of the present invention;

15 is an explanatory diagram of a third embodiment of the present invention;

16 is an explanatory diagram of an example of an electron gun;

17 is an explanatory diagram of an example of a main lens unit of an electron gun;

18 is an explanatory diagram of an example of a shadow mask used for a display tube.

<Description of the symbols for the main parts of the drawings>

1: Panel part

2: neck part

3 funnel section

4: fluorescent surface

5: shadow mask

101: horizontal deflection coil

102: separator

103: vertical deflection coil

11: bar type magnet

The first invention uses two electron quadrupoles to change the s dimensions at the center of the screen and the periphery of the screen in accordance with the deflection current. The two electron quadruple is provided on the cathode side of the electron gun rather than the horizontal deflection coil. As a result, the two electron quadrupoles are substantially provided outside the deflection magnetic field. Therefore, it is not necessary to greatly change the s dimension in the deflection magnetic field, and the control of convergence and purity becomes easy. According to the present invention, the practical s dimension for determining the curvature of the shadow mask can be greatly changed while maintaining the level of convergence and purity. Thereby, even if the outer surface is flat, a relatively large curvature can be given to a shadow mask, and a shadow mask can be maintained at practical intensity.

According to a second aspect of the present invention, when the electron beam scans the center of the screen, the first electron quadrupole lens has a function of moving the side electron beam farther than the center electron beam, and the second electron quadrupole lens has an action of making the side electron beam parallel to the center electron beam. Has With the increase in the deflection angle, the action of disengaging the side electron beam of the first electron quadrupole lens from the center beam is weakened, and the second electron quadrupole lens has the action of making the side electron beam parallel to the center electron beam. As a result, the substantial s dimension can be made smaller in the periphery of the screen than in the center of the screen, and the curvature of the shadow mask can be increased. In the second aspect of the invention, since the change in the s dimension can be reduced around the screen where convergence or purity cannot be controlled, the second electron quadrupole lens may be provided in the deflection magnetic field.

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

1 is a schematic diagram of a color CRT tube with an outer surface flat; The panel 1 has a flat outer surface and a curved inner surface. The inner surface of the panel has curvature in order to give the shadow mask 5 opposite the inner surface of the panel to have curvature. The neck 2 incorporates an electron gun 9 arranged inline, and is connected to the panel in the funnel portion 3. The intersection 32 between the reference line 31 and the tube axis is defined as the deflection center. The angle between the point where the electron beam 91 impinges on the fluorescent surface 4 and the line connecting the deflection center 32 and the tube axis is defined as a deflection angle. The reference line 32 is the basis of the design of the color water pipe, and is set on the panel side rather than the sealing portion of the neck and the funnel. Here, the maximum deflection angle means twice the angle formed between the diagonal axis end of the effective screen on the inner surface of the panel and the line connecting the deflection center 32 and the tube axis. The maximum deflection angle in this embodiment is about 110 degrees. On the fluorescent surface 4, a stripe-shaped phosphor is formed. The shadow mask 5 has a plurality of slot holes and is supported by the support frame 6. The support frame 6 is attached to the panel 1 by the spring 8. 2 shows an example of the slot hole arrangement of the shadow mask 5. Pm is the horizontal pitch of the slot 51. The internal magnetic shield 7 is attached to the support frame. A deflection yoke 10 for deflecting the electron beam is attached to the cone portion 33 of the funnel. The main portion of the deflection yoke 10 consists of a horizontal deflection coil 101, a separator 102, a vertical deflection coil 103, and a core 104. On the upper and lower sides of the horizontal deflection coil 101, rod-shaped magnets 11 for adjusting raster distortion and convergence are attached. The magnet assembly 12 adjusts the convergence or purity of the electron beam. The tension band 13 prevents the expansion of the valve. The first electron quadrupole coil 14 and the second electron quadrupole coil 15 are installed between the deflection yoke 10 and the magnet assembly 12.

The outer surface of the panel 1 is flat or has a very large radius of curvature. The curved surface of the panel is generally when Z is the amount of depression from the center of the panel,

Z = AlX ² + A2X ⁴ + A3Y ² + A4X ² Y ² + A5X ⁴ Y ² + A6Y ⁴ + A7X ² Y ⁴ + A8X ⁴ Y ⁴

Can be obtained by determining the coefficients A1 to A8. Table 1 and Table 2 are examples of the curved surface of the panel when the present invention is applied to a 36V type CPT.

Exterior: A1 0.1156035E-04 A5 -0.1309278E-19 A2 0.1545012E-14 A6 0.9600291E-14 A3 0.2125280E-04 A7 -0.3875353E-19 A4 -0.2866930E-10 A8 0.4856608E-25

Inside: A1 0.3839346E-04 A5 -0.5680002E-17 A2 0.5662136E-13 A6 0.3385039E-11 A3 0.1499420E-03 A7 -0.2802914E-16 A4 -0.4172959E-09 A8 0.6708166E-22

In such a panel, the curvature radius generally differs according to the place. As an evaluation of the flatness of the panel, an equivalent curvature radius by the amount of depression in the diagonal direction can be used as shown in FIG. In this case, as shown in Fig. 3, when half of the effective diameter in the diagonal direction is Dd and the amount of depression is Zd, the equivalent radius of curvature R in the diagonal direction can be expressed as Rd = (Dd ² + Zd ² ) / 2Zd. Even with the same radius of curvature, the effect on the flatness varies depending on the size of the screen. For this reason, as a representation method which standardized the flatness of the panel surface, Ro = 42.5V + 45.0mm for the outer surface and Ri = 40.0V + 40.0mm for the inner surface as a reference | standard (1R), and how many times this is There is a way to express flatness. Here, V is a numerical value representing the diagonal effective diameter in inches. If the outer curvature radius is 10R, it is known that the surface is almost planar. At 36V, the radius of curvature corresponding to 10R is 15750 mm. In addition, if it is 20R, it will be seen as a nearly perfect plane. The radius of curvature corresponding to this case is 31500 mm. The above panel outer surface is mostly equivalent thereto.

The panel has a larger curvature on the inner surface than the outer surface. In general, the shadow mask surface is approximately the same surface as the inner surface of the panel. The q dimension, the distance between the shadow mask and the inner surface of the panel, is represented by q = L × Pm / 3s. Where L is the distance from the deflection center to the shadow mask, Pm is the horizontal pitch of the mask, and s is the effective beam spacing on the deflection center. As can be seen from this equation, in order to increase the q dimension, the s dimension may be reduced. When the s dimension is reduced in the periphery of the screen, the q dimension is increased in the periphery of the screen, and the curvature of the shadow mask can be increased. Fig. 4 shows a conventional example using this principle. In Fig. 4, reference numeral 911 denotes an electron beam for scanning the center of the screen, and 912 denotes an electron beam for scanning the periphery of the screen. Each variable of q, L, and s denotes the value at the center of the screen as q0, L0, s0, and the values at the periphery of the screen as q1, L1, and s1. Fig. 4 uses two electronic quadrupole lenses to make the size s1 at the periphery of the screen smaller than the value s0 at the center of the screen, thereby increasing the q dimension at the periphery of the screen to give curvature to the shadow mask. The problem with this method is that in the deflection region of the electron beam including the deflection center, the actual s dimension is greatly changed, making it difficult to control convergence and purity on the screen. This is because both convergence and purity vary greatly with the value of the s dimension near the deflection center.

5 shows the present invention. Each code is the same as in FIG. In the present invention, the first electron quadrupole lens 14 and the second electron quadrupole lens 15 are provided on the cathode side of the electron gun rather than the horizontal deflection coil of the deflection yoke 10. As a result, when the electron beam enters the deflection region of the electron beam including the deflection center, the three electron beams are in a relationship substantially parallel to the CRT axis. Since three electron beams can be made substantially parallel in a sensitive area called a deflection area, control of convergence and purity is facilitated. 6 and 7 show schematic views in the vicinity of the deflection yoke of the present invention. 6 is a case where the electron beam is not deflected. No current flows through the pair of electron quadrupoles 14 and 15 and the electron beam goes straight. 7 shows a case where the electron beam is deflected, a current proportional to the deflection current flows through the first electron quadrupole coil 14 and the second electron quadrupole coil 15. 8 is a detailed view of the vicinity where the electron quadruple is attached. In this embodiment, an electron quadruple is attached to the shield cup of the electron gun. The electron quadrupole is preferably attached between the rear end of the horizontal deflection coil and the main lens of the electron gun. Since the electron quadrupole changes the s dimension, the effect after focusing through the main lens of the electron gun can be reduced. Fig. 9 shows a sectional view of the shield cup in this embodiment. Reference numerals 51 and 52 are pole pieces for forming the electron quadrupole. 10 and 11 are operation diagrams. FIG. 10 shows an operation in which the first electron quadrupole coil is attached near the cross section A-A in FIG. 9, and the s dimension of the electron beam is reduced. FIG. 11 shows an operation in which a second electron quadrupole coil is attached near the cross-section B-B in FIG. 9, and the electron beams on both sides are returned approximately parallel to the CRT axis. The pole pieces 51 and 52 are not essential, and in this case, the positions of the quadrupole coils 14 and 15 do not need to be in the vicinity of the shield cup 50. When the quadrupole coils 14 and 15 are integrated with the deflection yoke, adjustment is easy. In addition, the electromagnetic quadrupole coils 14 and 15 may be integrated with the magnet assembly 12. The first electron quadrupole coil may be integrated with the magnet assembly, and the second electron quadrupole lens may be integrated with the deflection yoke.

12 and 13 show a second embodiment of the present invention. In contrast to the first embodiment, this embodiment causes an electric quadruple coil to flow near the center of the screen to increase the s dimension. In this case, a current is generated through the first electron quadrupole coil 14 to generate a magnetic field which increases the s dimension, and a current is generated through the second electron quadrupole coil 15 to generate a magnetic field parallel to the CRT axis. Shed. As shown in Fig. 13, when the electron beam is deflected to the periphery of the screen, for example, at the screen diagonal end, no current flows to the electron quadrupole coil, and the s-dimension is left as it is. In this case, since the distance q between the shadow mask and the inner surface of the panel becomes small at the center, the curvature of the shadow mask can be large. This configuration is effective when an electron gun of a type having a small s dimension is used. This configuration also has the advantage that the q-dimension around the screen does not become extremely large, so that it is possible to reduce the harmful effects such as landing errors caused by geomagnetism around the screen. In this second embodiment, since the s-dimension does not change around the screen where convergence and purity cannot be controlled, the second electron quadrupole lens may be in a deflection magnetic field.

14 and 15 show a third embodiment of the present invention. In this embodiment, a current such as to effectively increase the s dimension in the center of the screen is passed through the electronic quadrupole coils 14 and 15, and the s dimension is effectively reduced in the periphery of the screen, for example, the screen diagonal end. An electric current similar to the above is applied to the electron quadrupole coils 14 and 15. An advantage of this embodiment is that the shadow mask can have a large curvature in the center of the screen and around the screen without having to change the size of the s dimension extremely. In the third embodiment, since the change in the s-dimension can be made small around the screen where convergence and purity cannot be controlled, the second electron quadrupole lens may be in a deflection magnetic field.

Fig. 16 is a longitudinal sectional view of an electron gun used in the present invention. In Fig. 16, reference numeral 40 is a cathode, and three are arranged at intervals of 55 mm in the direction perpendicular to the paper surface. From three cathodes a center electron beam and two side electron beams are emitted. Reference numeral 41 denotes a control electrode G1, and reference numeral 42 denotes an acceleration electrode G2. The front end lens is formed by the electrodes 43, 44 and 45. The static focus voltage Vfs is applied to the electrodes 43 and 45, and the same electrode as the acceleration electrode is applied to the electrode 44. These three electrodes form a so-called UPF lens. The electrodes 46, 47, and 48 are all focus electrodes, but are divided to form a lens having dynamic characteristics. A dynamic focus voltage at which the voltage increases with the deflection angle is applied to the electrodes 46 and 48, and a static focus voltage is applied to the electrodes 47. The hole formed at 451 is long horizontally, and the hole formed at 461 is vertically long. As a result, four electrostatic electrodes are formed together with the dynamic voltage. Reference numeral 462 denotes a horizontal plate electrode, and reference numeral 472 denotes a vertical plate electrode. By these two electrodes, another electrostatic quadrupole is formed. In each of the reference numerals 471 and 481, vertically long holes are formed, whereby the lens intensity changes with the dynamic voltage, and a lens is formed to lengthen the electron beam vertically. A positive voltage, which is the maximum voltage, is applied to the positive electrode 49, and a main lens is formed between the electrodes 48. This main lens has a small lens strength with increasing dynamic voltage. Reference numeral 482 denotes a plate-shaped electrode having a longitudinally long hole provided in the focus 48, and reference numeral 491 denotes a plate-shaped electrode having a longitudinally long hole installed in the anode electrode. 17 is a detailed view of the main lens unit. The internal electrodes 482 and 491 each have three longitudinally long holes, but may be holes only in the center. In the case where the fluorescent surface is flat, the focus deteriorates, especially in the periphery, but the deterioration of focus deterioration can be reduced by using dynamic focus. In addition, by using the large-diameter electron gun described in this embodiment, deterioration of focus at a large current can be reduced. The shield cup 50 is provided with pole pieces 51 and 52 for the electron quadrupole.

The above has been described for the CRT having a stripe-type fluorescent surface, but the same applies to the CRT having a fluorescent surface having a dot type, a shadow mask having round holes, and an electron gun arranged inline. This CRT is used as a high-precision display tube with a small dot pitch of the fluorescent surface. In this case, the holes of the shadow mask are arranged as shown in FIG. In the high precision tube, the horizontal pitch Pm of the shadow mask shown in Fig. 18 is 0.41 mm or less at the center of the screen. In this case, the shadow mask hole is about 0.11 mm. From the relationship with this hole diameter, the plate | board thickness of the shadow mask which has a big influence on a shadow mask intensity becomes thin as about 0.14 mm from the relationship of etching. Therefore, it is difficult to secure the shadow mask intensity unless the shadow mask has sufficient curvature. The present invention is particularly effective for such high precision display tubes.

In the deflection magnetic field, it is not necessary to greatly change the s dimension, and the control of convergence and purity becomes easy. According to the present invention, the practical s dimension for determining the curvature of the shadow mask can be greatly changed while maintaining the level of convergence and purity. Thereby, even if the outer surface is flat, a relatively large curvature can be given to a shadow mask, and a shadow mask can be maintained at practical intensity.

The substantial s dimension can be made smaller in the periphery of the screen than in the center of the screen, and the curvature of the shadow mask can be increased.

Claims (13)

A deflection yow having a panel having a fluorescent surface formed on its inner surface, a neck having an electron gun therein, a funnel portion connecting the neck and the panel, and a horizontal deflection coil and a vertical deflection coil for scanning the electron beam in the vicinity of the connection portion of the neck and the funnel. The electron gun has three cathodes arranged inline for generating a center electron beam and two side electron beams, and a plurality of electrodes and a shield cup for focusing the electron beams, The equivalent radius of curvature Rd (mm) in the diagonal direction of the outer surface of the panel is denoted by the numerical value representing the diagonal effective diameter in inches, and R is expressed in mm, R = 42.4V + 45.0 When set to Rd (mm) ≥ 10 R (mm), A first electron quadrupole lens having an action of bringing the side electron beam closer to or farther from the center beam in relation to the deflection angle of the electron beam, and a second acting in a direction to make the two side beams parallel to the center beam; It has a 2 electron quadrupole lens, The said 1st electron quadrupole lens and the said 2nd electron quadrupole lens are provided in the cathode side of the said electron gun rather than the horizontal deflection coil of the said deflection yoke. The method of claim 1, wherein the first electron quadrupole lens has an action of directing the two side electron beams in the direction of the center electron beam, with the increase of the deflection angle. A color CRT tube having a function of a direction in which a side electron beam is parallel to the center electron beam. The color CRT according to claim 2, wherein the intensity of the first electron quadrupole lens and the second electron quadrupole lens is zero when the electron beam scans the center of the screen. The method of claim 1, wherein when the deflection angle is zero, the first electron quadrupole lens has a function of moving the two side electron beams away from the center electron beam, and the second electron quadrupole lens has two side electron beams. Acts in a direction parallel to the center electron beam, and with the increase in the deflection angle, the action of moving the two side electron beams of the first electron quadrupole lens away from the center beam is weakened, and the second electron A quadrupole lens has a function of a direction in which the two side electron beams are parallel to the center electron beam. The color CRT according to claim 4, wherein the intensity of the first electron quadrupole lens and the second electron quadrupole lens is approximately zero when the electron beam scans the diagonal end of the screen. The method of claim 4, wherein when the electron beam scans the diagonal end of the screen, the first electron quadrupole lens has an action of directing the two side electron beams in the direction of the center electron beam, and the second electron quadrupole lens A color CRT tube having an action in a direction in which the two side electron beams are parallel to the center electron beam. The method of claim 1, wherein the relationship between Rd and R is Rd (mm) ≥20R (mm) Color CRT. According to claim 1, wherein the neck portion is provided with a magnet assembly for adjusting the convergence or purity, the coil forming the first electronic quadrupole lens and the coil formed with the second electrostatic quadrupole lens is the deflection yaw A color CRT tube, which is provided between the horizontal deflection coil of the chuck and the magnet assembly. A deflection yow having a panel having a fluorescent surface formed on its inner surface, a neck having an electron gun therein, a funnel portion connecting the neck and the panel, and a horizontal deflection coil and a vertical deflection coil for scanning the electron beam in the vicinity of the connection portion of the neck and the funnel. The electron gun has three cathodes arranged inline for generating a center electron beam and two side electron beams, and a plurality of electrodes and a shield cup for focusing the electron beams, The equivalent radius of curvature Rd (mm) in the diagonal direction of the outer surface of the panel is represented by the value expressed in inches of the diagonal effective diameter in V, R is expressed in mm, R = 42.4V + 45.0 When set to Rd (mm) ≥ 10 R (mm), When the deflection angle is zero, the first electron quadrupole lens has a function of moving the two side electron beams away from the center electron beam, and the second electrons having an action of making the two side electron beams parallel with the center electron beam. With a quadrupole lens, with the increase in the deflection angle, the action of moving the two side electron beams of the first electron quadrupole lens away from the center electron beam is weakened, and the second electron quadrupole lens has the two sides It has a function of the direction which makes the electron beam of a parallel with the said center electron beam, The color CRT tube characterized by the above-mentioned. 10. The color CRT according to claim 9, wherein the intensity of the first electron quadrupole lens and the second electron quadrupole lens is approximately zero when the electron beam scans the screen diagonal end portion. 10. The method of claim 9, wherein when the electron beam scans the screen diagonal end portion, the first electron quadrupole lens has an action of directing the two side electron beams in the direction of the center electron beam, and the second electron quadrupole lens And the two side electron beams in a direction parallel to the center electron beam. 10. The color CRT tube according to claim 9, wherein the first electron quadrupole lens is provided on the cathode side of the electron gun rather than the horizontal deflection coil of the deflection yoke. The method of claim 9, wherein the relationship between Rd and R is Rd (mm) ≥20R (mm) Color CRT.