JP3448898B2 - Cathode ray tube - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube capable of efficiently magnetizing members in the cathode ray tube for controlling the trajectory of the cathode ray in the cathode ray tube. 2. Description of the Related Art In a cathode ray tube, during the manufacturing process,
The fluorescent surface of the cathode ray (so-called electron beam) due to thermal deformation of the color selection electrode or glass tube, vacuum distortion when the glass tube is evacuated and sealed, or mechanical displacement of the color selection electrode. The arrival position of the vehicle may deviate from the original target position. Further, since the magnetic field at the place where the cathode ray is installed is different from the magnetic field at the place where the initial target position of the cathode ray is determined, the actual arrival position may be shifted due to the change of the magnetic field. Normally, a cathode ray tube in which the arrival position of a cathode ray is deviated from a target position has a problem that color misregistration or luminance reduction occurs. On the other hand, in order to correct the deviation of the cathode ray from the target position to reach the phosphor screen, a bias magnetic field is applied to the completed cathode ray tube by a ring coil surrounding the vicinity of the color selection electrode of the cathode ray tube. A method of applying an alternating-current damping magnetic field with a degauss coil in this state has been proposed (see Japanese Patent Application No. 61-133039). In a color cathode ray tube, for example, a color selection electrode 8 as shown in FIG. 15 is disposed so as to face the phosphor screen, and the frame 5 of the color selection electrode 8 has the influence of the terrestrial magnetism on the cathode ray and the color selection. An internal magnetic shield 10 for preventing reflection of a cathode ray by an electrode support spring or the like is attached. In the case of the drawing, the color selection electrode 8 is formed by welding a pair of U-shaped elastic members 3 and 4 so as to extend between both ends of a pair of opposed support members 1 and 2.
A frame-shaped interdigitated thin plate 9 composed of a number of grid elements 7 is stretched so as to have a slit-shaped cathode ray (electron beam) transmission hole 6 between the support members 1 and 2 of the frame 5. . [0007] As a method for correcting the deviation of the cathode ray from the target position to reach the phosphor screen, there are the following methods.
In addition to the above examples, the present applicant has previously proposed a method capable of correcting a more complicated orbital deviation or a local orbital deviation by magnetizing an arbitrary bias magnetic field on a member of a cathode ray tube. (See Japanese Patent Application No. 5-1290). When an arbitrary bias magnetic field is magnetized on a member of a cathode ray tube to control the trajectory of the cathode ray by using the magnetic field, the internal magnetism for reducing the influence by shielding the terrestrial magnetism in the cathode ray tube. Depending on the shape of the shield body 10, the magnetization efficiency may change. That is, even when the same magnetic field is applied to the cathode ray tube, the effect of correcting the trajectory of the cathode ray differs depending on the shape of the internal magnetic shield 10. Therefore, it has been necessary to develop a shape of the internal magnetic shield 10 in which the amount of magnetization changes efficiently in response to the change in the bias magnetic field, and as a result, the effect of correcting the trajectory of the cathode ray is enhanced. In view of the foregoing, the present invention provides a cathode ray tube having an internal magnetic shield, which can efficiently magnetize a magnetic field, particularly a horizontal magnetic field. According to the present invention, a large number of grit elements are provided so as to have a beam transmitting hole 6 in a frame 5 in which elastic members 3, 4 are connected between a pair of supporting members 1, 2. A color selection electrode 8 on which the body 7 is stretched, and an internal magnetic shield body 21 (25, 28, 4) attached to the frame 5.
1), the inner magnetic shield 21 (25, 28, 41) is connected to at least the frame 5
Of the frame 5 is shielded by 50% or more and the other part of the frame 5 is exposed. In the cathode ray tube according to the present invention, the internal magnetic field shield 21 (25, 28, 41) is connected to at least the support members 1, 2 and the elastic members 3 of the frame 5 of the color selection electrode 8. 4
Connecting portion and is shielded over 50% by the other portion of the frame 5 and shaped to be exposed, by magnetized (frame 5 in particular color selection electrode) member in the cathode ray tube,
When controlling the trajectory of the cathode ray by the magnetic field, the magnetization of the connecting portion 50 of the frame 5 is avoided, and the magnetic field at the connecting portion 50 is not disturbed. Therefore, overall,
Preferred magnetization is obtained, and the effect of correcting the trajectory of the cathode ray is enhanced. Embodiments of the present invention will be described below with reference to the drawings. First, the change in the trajectory of the cathode ray when a bias magnetic field is magnetized in a single direction with respect to the cathode ray tube will be described. As shown in FIG. 7, in the cathode ray tube 11 magnetized by a uniform magnetic field H from left to right toward the tube surface, as shown in FIG. Can be changed. In a cathode ray tube 11 magnetized by a uniform magnetic field H directed upward from below the tube surface as shown in FIG. 9, the trajectory of the cathode ray can be changed from a solid line 14A to a broken line 14B as shown in FIG. In the cathode ray tube 11 magnetized by a uniform magnetic field H perpendicular to the tube surface as shown in FIG. 11, the orbit of the cathode ray can be changed from the solid line 16A to the broken line 16B as shown in FIG. In a cathode ray tube 11 magnetized by a local magnetic field H oblique to the tube surface as shown in FIG.
As shown in FIG. 14, the trajectory of the cathode ray is changed from the solid line 18A to the broken line 18A.
B can be changed. (Embodiment 1) FIG. 1 and FIG. 2 show a color cathode ray tube according to the present embodiment, in particular, a color selection electrode 8 thereof and an internal magnetic shield 21 attached to the same. Color selection electrode 8
In the case of this example, a pair of U-shaped elastic members 3 and 4 are welded so as to extend between the vessel points at both ends of the pair of opposed support members 1 and 2 or the vicinity thereof. It has a frame 5, and is constructed by extending an interdigital thin plate 9 composed of a large number of grid elements 7 so as to have a slit-shaped beam transmitting hole 6 between the support members 1 and 2 of the frame 5. The inner magnetic shield body 21 forms a funnel-shaped ring body in which the frame 5 side corresponds to the outline of the frame and is squeezed toward the electron gun, and at least a welded portion between the support members 1 and 2 and the elastic members 3 and 4 That is, the connecting portion 50
Is formed in a shape integrally having four leg portions 22 for magnetically shielding the magnetic head. The leg 22 shields the connecting portion 50 and the vertical portion 23 of the elastic members 3 and 4 as viewed from the outside of the support members 1 and 2. FIG. 6 shows an example of a magnetizing device for correcting the trajectory of a cathode ray in a cathode ray tube. This magnetizing device 31
Are three pairs of coils 32 [32A, 32B, and 3] that function as a bias magnetic field generator that is disposed so as to be perpendicular to each other on each axis of the tube surface with respect to the cathode ray tube 11.
2C] and a coil 33 [33A, 33A,
33B]. In this magnetizing device 31, the coil 32
A, 32B and 32C determine the strength of the magnetic field, and apply an AC attenuating magnetic field by the coils 33A and 33B to magnetize a metal member such as a color selection electrode (especially a frame) in the cathode ray tube 11 to form a cathode ray. Control the trajectory. Using the magnetizing device 31 shown in FIG. 6, the color cathode ray tube provided with the color selection electrode 8 and the internal magnetic shield 21 shown in FIG. 1 is magnetized, and the orbit of the cathode ray shown in FIG. A change was generated, and the effect of correcting the trajectory of the cathode ray by the magnetization was evaluated. The measurement reference point of the magnetic flux density in the first embodiment is:
In all cases, the upper right end of the cathode ray tube surface. A magnetic field is generated in the coils 32A and 32C of the magnetizing device 31 under the following conditions. The magnitude of the magnetic field The direction of the magnetic field The coil 32A ··· 120μT The direction from left to right with respect to the tube surface The coil 32B · · · 35μT The direction from top to bottom with respect to the tube surface As shown in FIG. 2, the cathode ray tube 11 in which the ratio of the connection portion 50 shielded by the leg portion 22 of the internal magnetic shield 21 is changed (the shaded portion is shielded) is installed. Further, an alternating-current attenuation magnetic field of 600 μT is applied by the coils 33A and 33B. Table 1 shows the amount of change (μm) between the position of the cathode ray reaching the phosphor screen and the position of the cathode ray before magnetization in the cathode ray tube magnetized in this way. Table 1
Indicates the upper right of the change in the shape of the letter C. Since the strength of the magnetic field of the coil 32C is equivalent to that of the Japanese standard magnetic field, it is considered that the effect of correcting the trajectory of the cathode ray by the magnetization is obtained from the magnetic field of the coil 32A. [Table 1] (Embodiment 2) FIG. 3 shows a color cathode ray tube according to this embodiment, in particular, a color selection electrode 8 thereof and an internal magnetic shield 25 attached to the same. The color selection electrode 8 is formed by welding the U-shaped elastic members 3 and 4 as the frame 5 to the support members 1 and 2 so as to extend obliquely outward from the vessel point of the support members 1 and 2 or a portion in the vicinity thereof. Frame is used. Internal magnetic shield 25
Has a funnel-shaped ring as described above, and has elastic members 3 and 4 and support members 1 and 2 from outside the frame 5.
Are integrally formed with the L-shaped leg portions 26 for magnetically shielding the connecting portion 50 of the L-shaped portion. Then, using the magnetizing device 31 shown in FIG.
The color cathode ray tube provided with the color selection electrode 8 and the internal magnetic shield 25 shown in FIG. 3 was magnetized to cause a change in the trajectory of the cathode ray shown in FIG. 12, and the effect of correcting the trajectory of the cathode ray by the magnetization was evaluated. . The reference points for measuring the magnetic flux density in this embodiment are all at the upper right end of the surface of the cathode ray tube. A magnetic field is generated in the coils 32B and 32C of the magnetizing device 31 under the following conditions. The magnitude of the magnetic field The direction of the magnetic field The coil B ... 100 µT The direction of the coil C perpendicular to the tube surface, from front to back The coil C ... 35 µT The direction from the top to the bottom of the tube surface In this magnetic field, The cathode ray tube 11 in which the connection portion 50 is shielded by the leg portion 26 of the internal magnetic shield 25 at a different ratio is installed. Furthermore, the coils 33A, 33
B gives an AC attenuating magnetic field of 600 μT. Table 2 shows the amount of change (μm) between the position of the cathode ray reaching the phosphor screen in the cathode ray tube magnetized in this way and the position of the cathode ray before magnetization. The amount of change in Table 2 indicates the upper right of the change inclined with respect to the Y axis. Here, since the strength of the magnetic field of the coil 32C is equivalent to the Japanese standard magnetic field, it is considered that the effect of correcting the trajectory of the cathode ray by the magnetization is obtained from the magnetic field of the coil 32B. [Table 2] According to the first and second embodiments, the leg portions 22 and 26 are formed on a part of the internal magnetic shields 21 and 25, and the leg portions 22 and 26 connect the frame 5 to the connection portion (weld portion). By magnetically shielding 50, the so-called terrestrial magnetism drift can be improved by eliminating the influence of an external magnetic field due to the inner magnetic shields 21 and 25 themselves, and at the same time, the magnetizing of the frame 5 for correcting the trajectory of the cathode rays is performed. Can be set to a preferable state. That is, it is possible to form a preferable magnetic field that prevents disturbance of the magnetic field at the connecting portion 50 of the frame 5 and enhances the effect of correcting the trajectory of the cathode ray. As is apparent from Tables 1 and 2, it is preferable that the connecting portions 50 be shielded by 50% or more by the legs 23, 26 of the internal magnetic shields 21, 25. FIGS. 4 and 5 show still another embodiment of the present invention. In the example of FIG. 4, a frame formed by welding elastic members 3 and 4 between the extreme ends of the support members 1 and 2 is used as the frame 5 of the color selection electrode 8. On the other hand, the inner magnetic shield body 28 attached to the color selection electrode 8 also forms a funnel-like ring, and is welded to the elastic members 3 and 4 and the support members 1 and 2 from outside the frame 5. Part 2
A leg 29 for magnetically shielding from the surface side is integrally formed. FIG. 5 shows an example in which the frame 5 of the color selection electrode 8 has elastic members 3 and 4 between the extreme ends of the support members 1 and 2.
Is used. On the other hand, the internal magnetic shield body 41 attached to the color selection electrode 8 also forms a funnel-like ring body, and a connecting portion between the elastic members 3 and 4 and the support members 1 and 2 from the outside of the frame 5. 50
Is integrally formed with a leg 42 for magnetically shielding from one side. The embodiments of FIGS. 4 and 5 also provide the same effects as those of FIGS. 1 and 3. According to the cathode ray tube of the present invention, the internal magnetic shield is formed so as to shield at least the connecting portion between the support member and the elastic member of the frame of the color selection electrode, thereby providing the internal magnetic shield. It achieves the original effect of the shield body, that is, avoids the influence of an external magnetic field, and does not cause disturbance of the magnetic field at the connection portion when magnetizing the color selection electrode for correcting the trajectory of the cathode ray on the frame. Correct the trajectory of the cathode ray.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an example of a color selection electrode and an internal magnetic shield according to a cathode ray tube of the present invention. FIG. 2 is a side view for explaining the magnetic shield shown in FIG. 1; FIG. 3 is a side view showing another example of the color selection electrode and the internal magnetic shield according to the cathode ray tube of the present invention. FIG. 4 is a perspective view showing another example of a color selection electrode and an internal magnetic shield according to the cathode ray tube of the present invention. FIG. 5 is a perspective view showing still another example of a color selection electrode and an internal magnetic shield according to the cathode ray tube of the present invention. FIG. 6 is a perspective view showing an example of a magnetizing device. FIG. 7 is an explanatory diagram showing the direction of a bias magnetic field provided by a magnetizing device. 8 is an explanatory diagram showing a change in a trajectory of a cathode ray indicated by a cathode ray tube magnetized by generating a bias magnetic field of FIG. 7 by a magnetizing device. FIG. 9 is an explanatory diagram showing the direction of a bias magnetic field provided by a magnetizing device. 10 is an explanatory diagram showing a change in a trajectory of a cathode ray indicated by a cathode ray tube magnetized by generating a bias magnetic field in FIG. 9 by a magnetizing device. FIG. 11 is an explanatory diagram showing the direction of a bias magnetic field provided by a magnetizing device. 12 is an explanatory diagram showing a change in a trajectory of a cathode ray indicated by a cathode ray tube magnetized by generating a bias magnetic field of FIG. 11 by a magnetizing device. FIG. 13 is an explanatory diagram showing the direction of a bias magnetic field provided by a magnetizing device. 14 is an explanatory diagram showing a change in a trajectory of a cathode ray indicated by a cathode ray tube magnetized by generating the bias magnetic field of FIG. 13 by a magnetizing device. FIG. 15 is a perspective view showing an example of a color selection electrode and an internal magnetic shield according to a conventional cathode ray tube. [Description of Signs] 1, 2 support members 3, 4 elastic member 5 frame 6 beam transmission hole 7 grid element 8 color selection electrode 9 interdigital thin plates 10, 21, 25, 28, 41 internal magnetic shields 23, 26, 41 29, 42 leg 50 connecting part

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-61936 (JP, A) JP-A-54-110782 (JP, A) JP-A-56-147344 (JP, A) JP-A 47-107 12063 (JP, A) JP-A-6-223724 (JP, A) JP-A-62-290034 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 29/02

Claims (1)

(57) Claims 1. A color selection electrode in which a large number of grid elements are stretched so as to have a beam transmission hole in a frame in which an elastic member is connected between a pair of support members. And a cathode ray tube having an internal magnetic shield attached to the frame, wherein the internal magnetic shield forms at least 50% or more of a connection portion of the frame so as to expose the other part of the frame. A cathode ray tube characterized by being made.