JPS61224247A - Color cathode-ray tube associated with deflector - Google Patents

Abstract

PURPOSE:To easily reproduce a picture image having excellent color purity and no mislanding in rotary direction by arranging a supporting device such that the shadowmask is rotated in the direction for cancelling the mislanding caused through rotation of electron beam around the axis of tube. CONSTITUTION:For a deflector fixed such that S-pole of permanent magnet 10 or magnetic bias of saturable reactor will come to the magnetic core 3 side (N-pole is at the outside) of deflection yoke 6, a supporting device 31 is arranged such that the frame holder 30 will position the shadowmask 22 in right rotary direction around the tube axis when viewed from the electron gun 25 side against a panel pin 29. While for a deflector fixed such that N-pole of permanent magnet 10 will come to the magnetic core 3 side of deflection yoke 6 (S-pole is at the outside), the supporting device 31 is arranged such that the frame holder 30 will position the shadowmask 27 in left rotary direction around the tube axis when viewed from the electron gun 25 against the panel pin 29 as shown by arrow D for the panel pin 29.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a color cathode ray tube with a deflection device that improves landing characteristics.

[Technical background of the invention and its problems]

As the resolution of color cathode ray tubes increases, there is a tendency for deflection devices to be required to have even higher performance in terms of convergence characteristics and bias distortion performance. In order to meet such demands,
A deflection device has been developed that adds an auxiliary coil to the deflection yoke, dynamically shapes the magnetic field distribution, and can achieve high convergence characteristics. For example, JP-A-58-1445
As shown in No. 3 Publication tμ, an auxiliary coil using a permanent magnet as a magnetic bias is magnetically coupled to the magnetic core of the deflection yoke, and connected in series with the horizontal deflection coil to form a saturable reactor. One example is a deflection device that is operated to control the horizontal deflection current to form an appropriate horizontal magnetic field distribution and improve convergence characteristics.

As shown in FIGS. 5 and 6, this deflection device includes a horizontal deflection coil (2) incorporated in a separator (1),
and a vertical deflection coil (
5), and a magnetic core (3) of the deflection yoke (6), which is attached symmetrically to the magnetic core (3) and the vertical deflection coil (5). and a pair of auxiliary coils (7). Each auxiliary coil (7) includes a pair of i-crumb-shaped iron cores (8) fixed to the J-magnetomotive core (3) and magnetically closely coupled to this magnetic core (3), and the above-mentioned horizontal deflection coil. A coil (2) connected in series to wind this pair of iron cores (8) (
9), and a permanent magnet (]O) attached to the distal end surface of the iron core (8) and magnetically closely coupled to the iron core (8). This auxiliary coil (7) operates as a saturable reactor synchronized with the vertical deflection, and the operating point of this saturable reactor is the permanent magnet (10
) is determined by the magnetic force of the water XIZ deflection coil (
2) Horizontal deflection current I+11. In order to control l112 in a well-balanced manner, the permanent magnet (10) is
They are attached to a pair of auxiliary coils (7) with the same polarity facing each other, and in the illustrated example, the N pole is shown on the outside.

When the auxiliary coil (7) is configured as described above, the magnetic core (3) of the deflection yoke (6) is the iron core (8) of the auxiliary coil (7).
It is magnetically closely coupled with the permanent magnet (10) through the magnet, creating a static magnetic field configuration as if the entire magnetic core (3) were an S pole, forming a magnetic field distribution with the components shown by arrows (A) in Figure 7. do. When such a magnetic field is configured, the electron beam receives a rotational deflection in addition to the predetermined horizontal and vertical deflections, and as seen from the front of the color cathode ray tube, as shown by the arrow (B) in FIG. Misland ink occurs due to clockwise rotation around the tube axis (counterclockwise rotation from the electron gun side). The amount of misland ink varies depending on the inner diameter of the deflection device and the magnetization strength of the permanent magnet (10), but it has been experimentally measured to be about 10 μm.

In color cathode rays with high definition and a small landing margin for the electron beam, this misland ink amount is large enough to impair color purity. In order to eliminate this mislandish ink, it is possible to form a phosphor screen by designing an exposure lens that takes into account the amount of mislandish ink based on the rotation of the electron beam, but such a lens design is currently not possible. It's difficult and short.

[Purpose of the invention]

The object of the present invention is to construct a color cathode ray that can easily reproduce images with excellent color purity and no mislandish ink in the rotational direction.

[Summary of the invention]

A shadow mask is attached to the inside of the envelope by at least three sets of support devices, facing the phosphor screen formed on the inner surface of the panel, and the electron beam incident on the phosphor screen via the shadow mask is A color cathode ray tube has an electron gun that emits a plurality of electron beams so as to be concentrated at a central point, and is magnetically coupled to a deflection yoke that horizontally and vertically deflects the electron beams emitted from the electron gun, and has a magnetic bias. and shaping the horizontal magnetic field distribution of the deflection yoke by controlling the horizontal deflection current flowing through the horizontal deflection coil of the deflection yoke by using the auxiliary coil as a saturable reactor. In a color cathode ray tube with a deflection device, which is equipped with a deflection device configured to correct the concentration deviation of the electron beam, canceling misland ink caused by rotation of the electron beam around the tube axis caused by the magnetic field distribution of the deflection device. By arranging the supporting device so as to be able to rotate the shadow mask in the direction, the configuration is such that mislanding in the direction of rotation is desired.

[Embodiments of the invention]

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

FIG. 1 shows the overall structure of a color cathode ray tube with a deflection device, which is an embodiment of the present invention. In the color cathode ray tube of this embodiment, a phosphor screen (21) made of three-color phosphors is formed on the inner surface of the front surface of a panel (20) configured in the shape of a rectangular dish, and a phosphor screen (21) made of three-color phosphors is formed opposite to the phosphor screen (21). As if inside,
A spherical shadow mask (22) corresponding to the spherical front surface of the panel (20) is disposed at a certain distance from the inner surface of the panel (20). Also, in the neck part (24) of the funnel (23), which together with the panel (20) constitutes an envelope, there is an electron gun ( 25) is provided.

The shadow mask (22) includes a mask body (27) in which a large number of through holes are formed in a predetermined arrangement, and a frame (27) that holds the mask body (27) with a skirt portion around the mask body (27).
28), and as shown in Figure 2, the panel (20
) A panel pin (29) (first support) fixed to the inner surface of the side wall of the panel pin (29) extends along the side of the frame (28), and an engagement hole formed at the tip end of the panel pin (29)
It is supported by a support device (31) consisting of a leaf spring-shaped frame holder (30) (second support) whose base end is fixed to the frame (28) by welding or the like, and the rectangular shape The shadow mask (22) is supported by at least three sets of support devices (31), with one set provided on each of its four sides or any three selected sides.

The deflection device (33) is disposed outside the funnel (23) of the color cathode ray tube, and its structure is similar to that of the fifth tube.
Since it is the same as the deflection device shown in FIG. 1 and FIG. 6, the same parts in FIG. 1 are given the same numbers and detailed explanation thereof will be omitted.

When the shadow mask (22) is supported by at least three sets of support devices (31) as described above, these support devices (3
In the arrangement of 1), for example, as shown in FIG. 3, when the frame holder (30) is arranged with respect to the panel pin (29) so as to be positioned in the same rotation direction around the tube axis,
The shadow mask (22) is applied to the panel (20),
Thermal factors cause rotation, which is thought to be the main cause. This rotation is in the direction in which the frame holder (30) extends with respect to the panel pin (29) fixed to the panel (20), and in the example of FIG. When viewed from the gun (25) side, the rotation is clockwise around the tube axis. The direction caused by the rotation of this shadow mask (22) is the same as the direction of the misland ink caused by the deflection device.
It is φ. Also, the amount of misland ink varies depending on the length and material of the frame holder (30), but it is between 6 and 20.
It is about 5 to 15 μm for a 1/2-inch color cathode ray tube, and is approximately the same size as the amount of misland ink based on the magnetic field of the deflection device.

Therefore, the S pole of the permanent magnet (10), which is the magnetic bias of the saturable reactor, is on the magnetic core (3) side (N
The deflection device (the fifth
6), the frame holder (30) is attached to the panel pin (29) as shown in FIG.
The support device (31
). In addition, for a deflection device that is attached so that the N pole of the permanent magnet (10) is on the magnetic core (3) side of the deflection yoke (6) (the S pole is on the outside), as shown in FIG. As shown by the arrow (D) with respect to the panel pin (29), the frame holder (30)
) is positioned so that the shadow mask (27) is located in the counterclockwise rotation direction around the tube axis when viewed from the electron gun (25).
).

As mentioned above, depending on the polarity of the permanent magnet (10) which is the magnetic bias of the saturable reactor of the deflection device, the support device (
31), it is possible to significantly improve the mislanding in the rotational direction that occurs based on the magnetic field of the deflection device (33) having a saturable reactor. According to the experimental results, it is confirmed that the combination of the above-mentioned deflection device and support device can suppress the amount of misland ink in the rotational direction to a maximum of 5 μm, a size that can be sufficiently tolerated even in high-definition color cathode ray tubes. J was shunned.

〔Effect of the invention〕

When using a deflection device having a saturable reactor, if the support device is arranged in a direction that rotates the shaft to the right or left depending on the polarity of the permanent magnet that is the magnetic bias of the saturable reactor, the above-mentioned Misland ink in the rotational direction caused by the magnetic field of the deflection device can be significantly improved, and a color cathode ray tube with a deflection device with excellent color purity can be constructed.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view showing the overall configuration of a color cathode ray tube with a deflection device according to an embodiment of the present invention, FIG. 2 is a view showing a support device for a shadow mask of the color cathode ray tube, and FIG. 4 and 4 respectively show different arrangements of the support device, FIG. 5 is a front view of the deflection device with the saturated axles 1 to 4, FIG. 6 is the same sectional view, and FIG. A diagram showing the magnetic field distribution inside the magnetic core of the deflection yoke that occurs when the N pole of the permanent magnet that constitutes the saturation reactor is placed outside,
FIG. 8 is a diagram showing the direction of misland ink generated based on the above magnetic field distribution. (2)...Horizontal deflection coil (3)...Magnetic core (5)...
Vertical separate coil (6)...Deflection yoke 1l- (7)...Auxiliary coil (20)...Panel (2
1) Fluorescent screen (22) Shadow mask (25) Electron gun (28) Frame (29) Panel pin (first support) (30)
... Frame holder (second support body) (31) ... Support device (33) ... Deflection device agent Patent attorney
Figure 1 Figure 2 Figure Δ To the meeting - Figure 5 Figure 6 Figure 7 Figure 8

Claims (3)

[Claims] (1) A shadow mask is attached to the inside of the envelope by at least three sets of support devices so as to face the phosphor screen formed on the inner surface of the panel, and the electron beam incident on the phosphor screen via the shadow mask emits the phosphor screen. A color cathode ray tube having an electron gun that emits a plurality of electron beams so as to be concentrated on a surface, a deflection yoke that deflects the electron beams emitted from the electron gun in horizontal and vertical directions, and a magnetically connected to the deflection yoke. It has an auxiliary coil coupled to it and given a magnetic bias, and this auxiliary coil is used as a saturable reactor to control the horizontal deflection current flowing through the horizontal deflection coil of the deflection yoke, thereby shaping the horizontal magnetic field distribution of the deflection yoke. and a deflection device configured to correct the concentration deviation of the electron beam, the shadow being directed in the direction of canceling misland ink caused by the rotation of the electron beam around the tube axis caused by the magnetic field distribution of the deflection device. A color cathode ray tube with a deflection device, characterized in that the support device described above is arranged so that the mask can be rotated. (2) The support device extends in the direction of rotation around the tube axis along the first support fixed to the inner surface of the panel and the side of the shadow mask, and the tip engages with the first support. For a deflection device having a second support whose base end is fixed to the shadow mask, and an auxiliary coil whose polarity on the magnetic core side of the deflection yoke of the magnetic bias is the S pole, each support device has the second support body fixed to the shadow mask. Claims characterized in that the base end portion of the second support body is disposed relative to the first support body so that the base end portion of the second support body is positioned in a clockwise rotation direction around the tube axis when the shadow mask is viewed from the electron gun side. A color cathode ray tube with a deflection device according to item 1. (3) The support device extends in the direction of rotation around the tube axis along the side of the first support fixed to the inner surface of the panel and the shadow mask, and the tip engages with the first support. For a deflection device having a second support whose base end is fixed to the shadow mask, and an auxiliary coil whose polarity on the magnetic core side of the deflection yoke of the magnetic bias is N pole, each support device has the second support body fixed to the shadow mask. Claims characterized in that the base end portion of the second support body is disposed relative to the first support body so that the base end portion of the second support body is positioned in the counterclockwise rotation direction around the tube axis when the shadow mask is viewed from the electron gun side. A color cathode ray tube with a deflection device according to item 1.