JPH07211257A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE:To correct green right slurring due to coma-aberration of a deflection device and prevent color displacement. CONSTITUTION:A color cathode-ray tube has an electron gun 24 for emitting 3 electron beams arranged in a row in which a convergence cup 28 is mounted on an electrode positioned on a phosphor screen 22 side. 3 electron beams emitted from this electron gun are deflected by the horizontal and vertical deflection magnetic fields generated by a deflection device 27, and a phosphor screen is scanned. In this color cathode-ray tube, a stepped part of the convergence cup is formed on a side wall on an axis perpendicular to its center axis and an array axis of 3 electron beams, and a slit-shaped cut-out opened on the opening side of the convergence cup is formed on the side wall of the stepped part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to a color cathode ray tube which reduces the color shift between the left and right of the screen of the inline type color cathode ray tube.

[0002]

2. Description of the Related Art Generally, in a color cathode ray tube, a shadow mask is arranged so as to face a phosphor screen composed of three-color phosphor layers which emit blue, green and red, and deflects three electron beams emitted from an electron gun. The structure is formed to display a color image by deflecting by horizontal and vertical deflection magnetic fields generated by the apparatus, selecting the three electron beams by a shadow mask, and scanning the phosphor screen. In such a color cathode ray tube, in particular, the electron gun is an electron gun that emits three electron beams arranged in a line consisting of a center beam and a pair of side beams that pass on the same horizontal plane, and the three electron beams arranged in a line form a stripe shape. There is an in-line type color cathode ray tube configured to scan a phosphor screen including the three-color phosphor layer.

This in-line type color cathode ray tube is shown in FIG.
As shown in FIG.
By making H a pincushion type and a vertical deflection magnetic field 1V barrel type, the three electron beams 2B, 2G and 2R are concentrated at one point on the phosphor screen without using any special member for assembling the color cathode ray tube ( Static concentration), and when it is incorporated into a color receiver, it can be concentrated (dynamic concentration) without requiring special correction by an external circuit, and as a so-called self-convergence in-line type color cathode ray tube, 3 electron beams 2B, 2G, 2R
There is an advantage that the complicated centralized adjustment of can be eliminated.

However, in reality, assuming that the horizontal and vertical deflection magnetic fields 1H and 1V generated by the deflecting device are non-uniform magnetic fields, as shown in FIG. As shown, the center beam scanning screen 3G and the pair of side beam scanning screens 3B, 3
A concentrated error occurs that R does not match.

Therefore, in the conventional self-convergence in-line type color cathode ray tube, as shown in FIG. 6, a pair of side beam passage holes 4B are provided inside the bottom of the convergence cup attached to the beam emission end of the electron gun. , 4R, a magnetic field control element 5 made of a high magnetic permeability material is arranged, and three electron beams 2B, 2G, 2R are arranged.
The concentration of the three electron beams 2B, 2G, and 2R is corrected by controlling the rear leakage magnetic field of the deflecting device for.

However, the magnetic field control element 5 as shown in FIG.
When the concentration of the three electron beams 2B, 2G, and 2R is corrected by, the difference between the correction amount for the center beam 2G and the correction amount for the pair of side beams 2B, 2R is shown in FIG.
As shown in FIG. 3, a phenomenon occurs in which the pair of side beam scanning screens 3B and 3R are displaced to the left side with respect to the center beam scanning screen 3G. This phenomenon is generally referred to as green shift to the right, and is particularly prominent in a recent deflection system having a high horizontal deflection frequency.

This green right shift is caused by the following causes. That is, an eddy current is generated on the side wall of the convergence cup due to the passage of the rearward-deflection rearward leakage magnetic field, and the magnetic flux generated by this eddy current reduces the magnetic flux of the rearward-deflection rearward leakage magnetic field passing through the side wall of the convergence cup. The decrease in the magnetic flux of the leakage magnetic field at the rear part of the horizontal deflection due to the eddy current can be ignored at the low frequency of the conventional horizontal deflection frequency fh = 15.75 kHz, but the horizontal deflection frequency fh
As the value becomes higher, it cannot be ignored, and as shown in FIG. 5, the pair of side beam scanning screens 3B and 3R spread laterally with respect to the center beam scanning screen 3G.

On the other hand, the waveform of the current flowing through the horizontal deflection coil of the deflection device is a sawtooth wave 7 as shown in FIG.
The time t1 from the point a to the point b of the sawtooth wave 7 is the horizontal scanning period, and the time t2 from the point b to the point c is the horizontal retrace line period. The points a and c are the left end of the horizontal scanning and the point b. Corresponds to the right end, and normally t2 is set to about 1/5 of t1. In this case, the amount of change in magnetic flux when moving from horizontal scanning to horizontal retrace is the same as the amount of change in magnetic flux when moving from horizontal retrace to horizontal scan, but when changing from horizontal scan to horizontal retrace, Since the signal is cut, it has no effect on the screen. Therefore, a great influence appears at the left end of the screen where horizontal scanning starts. That is, when the horizontal deflection frequency is increased, the change in the magnetic flux due to the eddy current loss due to the high frequency component magnetic field is larger on the left side than on the right side of the screen. for that reason,
As shown in FIG. 7, the pair of side beam scanning screens 3B and 3R are displaced to the left side with respect to the center beam scanning screen 3G, and asymmetrical coma aberration appears in the horizontal direction. The pair asymmetry of the pair of side beam scanning screens 3B and 3R with respect to the center beam scanning screen 3G increases as the horizontal deflection frequency increases, and in order to increase the horizontal scanning period (effective scanning period), It increases when the blanking period is set small.

As means for correcting such coma aberration, Japanese Patent Laid-Open Nos. 61-29046 and 61-
No. 29047, as shown in FIGS. 9 (a) and 9 (b), a plurality of slit-shaped openings 10a or larger openings 10a are formed in the side wall of the convergence cup 9.
By forming b, the generation of eddy current due to the horizontal deflection rear leakage magnetic field passing through the side wall is suppressed, and the reduction of the magnetic flux of the horizontal deflection rear leakage magnetic field passing through the side wall of the convergence cup 9 is eliminated. It is shown. However, even if such openings 10a and 10b are formed, the convergence cup 9 cannot sufficiently suppress the eddy current because its opening end (end on the phosphor screen side) is connected. .

On the other hand, Japanese Unexamined Patent Publication No. 60-86739 discloses that the side wall of the convergence cup 9 is provided with a notch 11 communicating with the opening on the phosphor screen side as shown in FIG. Has been done. By providing the notch 11 communicating with the opening on the phosphor screen side of the convergence cup 9 in this way, the reduction of the magnetic flux of the horizontal deflection rear leakage magnetic field due to the eddy current generated by the horizontal deflection rear leakage magnetic field passing through the side wall is prevented. it can.

However, when the notch 11 communicating with the opening on the phosphor screen side is provided in this way, as shown in FIG. 11, the neck 12 of the inner conductive film 13 which is usually applied from the inner surface of the funnel to the inner surface of the adjacent portion of the neck 12 is formed. The side end portion is at a position facing the side wall middle portion of the convergence cup 9, the notch 11 is not completely covered by the inner conductive film 13, and the end of the inner conductive film 13 on the neck 12 side and the notch 11 are formed.
A gap indicated by the dimension s is formed between the bottom and the bottom. Therefore, from the anode terminal provided on the funnel to the inner conductive film 1
3 and the anode voltage Eb applied to the convergence cup 9 via the valve spacer 14 that is pressed against the inner conductive film 13 and the penetration from the inner surface of the neck 12 adjacent to the end of the inner conductive film 13 on the neck 12 side. Voltage Eb '
Due to the difference between (Eb> Eb '), as shown in FIG.
Center beam 2G and pair of side beams 2B, 2
The electric field with respect to R becomes non-uniform, and the force F for horizontally extending the center beam 2G acts, deteriorating the focus characteristics of the color cathode ray tube.

In order to prevent the deterioration of the focus characteristic, as shown in FIG. 13, the inner conductive film 13 applied to the inner surface of the neck 12 is extended so as to completely cover the side wall of the convergence cup 9. However, when the inner conductive film 13 is extended in this way, when the electron gun is inserted into the neck 12 in the manufacturing process of the color cathode ray tube,
The inner conductive film 13 is rubbed by friction with the valve spacer 14.
When the color cathode ray tube is subjected to a withstand voltage treatment which is subsequently peeled off, a spark discharge is generated between the inner conductive film 13 and the electrode of the electron gun to deteriorate withstand voltage characteristics.

[0013]

As described above, the self-convergence in-line type color cathode ray tube concentrates the three electron beams arranged in a row and emitted from the electron gun by the magnetic field distribution of the deflecting device. , The eddy current is generated on the side wall of the convergence cup attached to the beam emission end of the electron gun due to the passage of the rear leakage magnetic field of the deflection device, and the magnetic flux generated by this eddy current passes through the side wall of the convergence cup. Since the magnetic flux of the rear leakage magnetic field of the device is reduced, a concentration error occurs in which the scanning screens of the pair of side beams spread laterally with respect to the scanning screen of the center beam. Conventionally, in order to correct the concentration error of the three electron beams due to the coma aberration of the deflection magnetic field, the convergence
A magnetic field control element made of a high magnetic susceptibility material is arranged at the bottom of the cup to control the rear leakage magnetic field of the deflector for the three electron beams. However, when the concentration of the three electron beams is corrected by this magnetic field control element, the correction amount for the center beam and the correction amount for the pair of side beams are different, especially when the horizontal deflection frequency is increased, so that the center beam scanning screen is A so-called green right shift occurs in which the pair of side beams are displaced to the left side of the scanning screen.

As a means for correcting the concentration error due to such coma aberration, conventionally, a slit-shaped opening or the like is formed in the side wall of the convergence cup to form a convergence.
It is known that the generation of eddy currents due to the horizontal deflection rear leakage magnetic field passing through the side wall of the cup is suppressed, and the reduction of the magnetic flux of the horizontal deflection rear leakage magnetic field passing through the side wall of the convergence cup is eliminated. However, even if the aperture is formed in this way, the convergence cup cannot connect the open end on the phosphor screen side, so that the eddy current cannot be sufficiently suppressed to eliminate the concentration error.

As another means for correcting the concentration error due to coma aberration, it is known to provide a notch on the side wall of the convergence cup, the notch communicating with the opening on the phosphor screen side. However, if a notch is formed through the opening on the phosphor screen side, the neck side end of the inner conductive film applied from the inner surface of the funnel to the inner surface of the adjacent part of the neck faces the middle part of the side wall of the convergence cup. Since the notch is not completely covered by the inner conductive film, the electric field for the center beam and the pair of side beams is nonuniform due to the permeation voltage Eb ′ from the inner surface of the neck adjacent to the neck side end of the inner conductive film. Next to
A force F that makes the center beam horizontal is applied to deteriorate the focus characteristics of the color cathode ray tube. In order to prevent the deterioration of the focus characteristics, the inner conductive film applied to the inner surface of the neck may be extended so as to completely cover the side wall of the convergence cup. When extended, when the electron gun is inserted into the neck in the manufacturing process of the color cathode-ray tube, the inner conductive film is peeled off due to friction with the valve spacer, etc. Spark discharge is generated between the electron gun and the electrode, which causes problems such as deterioration in withstand voltage characteristics.

The present invention has been made in view of the above problems, and in a self-convergence in-line type color cathode ray tube, even if the horizontal deflection frequency becomes high,
An object of the present invention is to configure a color cathode ray tube in which a pair of side beam scanning screens do not shift with respect to a center beam scanning screen.

[0017]

An electron gun for emitting three electron beams arranged in a row, in which a plurality of electrodes are arranged from the cathode in the phosphor screen direction, and a convergence cup is attached to the electrodes located on the phosphor screen side. Have
In a color cathode ray tube that scans a phosphor screen by deflecting three electron beams emitted from this electron gun by horizontal and vertical deflection magnetic fields generated by a deflecting device, the convergence cup is connected to the central axis of the convergence cup and the three points. A step portion is formed on the side wall on an axis orthogonal to the arrangement axis of the electron beam, and a slit-like notch opening to the opening side of the convergence cup is formed in this step portion.

[0018]

As described above, the convergence cup is formed with the step portion on the side wall on the axis orthogonal to the central axis and the arrangement axis of the three electron beams, and the convergence portion is formed on the step portion.
If a slit-shaped cutout is formed on the opening side of the cup, the slit cutout causes the magnetic flux of the horizontal deflection rear leakage magnetic field due to the eddy current generated by the horizontal deflection rear leakage magnetic field passing through the side wall of the convergence cup. Can be prevented, and even if the horizontal deflection frequency becomes high, it is possible to eliminate the deviation of the scanning screen of the pair of side beams from the scanning screen of the center beam due to coma.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows a color cathode ray tube which is an embodiment thereof. The color cathode ray tube includes a panel 20 and a funnel-shaped funnel 21 integrally joined to the panel 20.
The outer surface of the panel 20 is blue,
A phosphor screen 22 composed of a stripe-shaped three-color phosphor layer that emits green and red light is formed, and a shadow mask 23 is arranged inside the phosphor screen 22 so as to face the phosphor screen 22. On the other hand, in the neck 12 of the funnel 21, an electron gun 24 that emits three electron beams 2B, 2G, 2R arranged in a row consisting of a center beam 2G passing through the same horizontal plane and a pair of side beams 2B, 2R is arranged. There is. An anode terminal 26 is provided on the large-diameter portion 25 of the funnel 21, and the neck 1 is attached to the inner surface of the large-diameter portion 25.
An inner surface conductive film 13 is formed by coating on the inner surface of the adjacent portion of 2. The three electron beams 2B, 2G and 2R emitted from the electron gun 24 are mounted on the outside of the funnel 21 and are deflected by the horizontal and vertical deflection magnetic fields generated by the deflector 27, and the three electron beams 2B, 2G and 2R is selected by the shadow mask 23, and the phosphor screen 22 is selected.
By scanning horizontally and vertically the phosphor screen 2
2 has a structure for displaying a color image.

The electron gun 24 comprises three cathodes arranged in a line on the same horizontal plane, three heaters for heating the cathodes separately, and the phosphor screen 2 from the cathodes.
It has a plurality of electrodes sequentially arranged at predetermined intervals in two directions, and a convergence cup 28 made of a non-magnetic material is attached to the electrode located on the phosphor screen 22 side. At the bottom of the plurality of electrodes and the convergence cup 28, three electron beam passage holes are formed corresponding to the cathodes arranged in a row.

The end of the inner conductive film 13 formed on the inner surface of the funnel 21 on the side of the neck 12 is located at a position corresponding to the middle portion of the side wall of the convergence cup 28. Anode terminal 2
An anode voltage is applied from 6 through the inner conductive film 13 and a valve spacer (not shown) attached to the convergence cup 28 and in pressure contact with the inner conductive film 13.

Particularly in the color cathode ray tube of this example,
As shown in FIG. 2, the side wall of the convergence cup 28 has a central axis Z (which coincides with the tube axis) of the convergence cup 28 and three electron beam passage holes 29B, 29G and 29R provided at the bottom thereof. The stepped portion 30 is provided on the vertical axis by pushing the side wall at the rotationally symmetrical position into the cup with the vertical axis Y orthogonal to the arrangement axis X (horizontal axis) of the three electron beams 2B, 2G, 2R passing through. , This step 3
The slit-shaped notch 32 communicating with the opening 31 on the phosphor screen side of the convergence cup 28 is formed at 0. The notch 32 reaches the middle portion of the side wall.

In this way, the convergence cup 28 is attached to the side wall of the convergence cup 28 made of a non-magnetic material attached to the phosphor screen side 22 of the electron gun 24.
Of the central axis Z and the vertical axis Y orthogonal to the array axis X of the three electron beams 2B, 2G and 2R, and the step portion 30 is provided in the opening 31 on the phosphor screen 22 side of the convergence cup 28. When the slit-shaped cutout 32 is formed, the eddy current generated in the convergence cup 28 due to the passage of the horizontal deflection rear leakage magnetic field of the deflecting device 27 is passed by the slit-shaped cutout 32 in the vicinity of the center beam passage hole 29G. No eddy current is generated in the deflected rear leakage magnetic field, and the pair of side beam passage holes 29
Eddy currents are generated only by the horizontal deflection rear leakage magnetic field passing near B and 29R.

This pair of side beam passage holes 29B, 2
The eddy current generated by the horizontal deflection rear leakage magnetic field passing near 9R acts in the direction of hindering the horizontal deflection rear leakage magnetic field passing the side wall of the convergence cup 28. Therefore, a pair of side beam passage holes 2 are applied to the horizontal deflection rear leakage magnetic field passing through the center beam passage hole 29G.
Delay the phase of the horizontal deflection rear leakage magnetic field passing through 9B and 29R. As a result, the phase of the horizontal deflection rear leakage magnetic field passing through the center beam passage hole 29G leads the phase of the horizontal deflection rear leakage magnetic field passing through the pair of side beam passage holes 29B and 29R, and passes through the center beam passage hole 29G. Cancels the phase delay of the center beam 2G.

Since the convergence cup 28 is made of a non-magnetic material, the horizontal deflection magnetic field having a high frequency causes a strong phase change, but the vertical deflection magnetic field having a low frequency has no effect. Therefore, the slit-shaped notch 32 of the convergence cup 28 of this example can correct any amount of green shift to the right by adjusting the width and depth of the horizontal deflection magnetic field only.

Also, the convergence cup 28 of this example
Then, the central axes Z and 3 of the convergence cup 28 are
Since the step portion 30 is provided on the vertical axis Y which is orthogonal to the arrangement axis X of the electron beams 2B, 2G and 2R, and the slit-shaped notch 32 is formed in the step portion 30, the Japanese Patent Publication No. 60-867.
In the case of the convergence cup disclosed in Japanese Patent No. 39, the problem is prevented that the voltage penetrates from the inner surface of the neck that generates a force to make the center beam laterally long, and the focus characteristic is prevented from deteriorating.

Moreover, the convergence cup 2 of this example
8, the step portion 30 is provided from the opening side of the convergence cup 28 to the bottom portion thereof.
Higher mechanical strength and higher accuracy than the convergence cups having slit-shaped openings or notches shown in JP-B-046, JP-B-61-29047 or JP-B-60-86739. Can be a convergence cup.

In the above embodiment, the side wall at the rotationally symmetric position is pushed into the cup with the vertical axis of the convergence cup interposed therebetween to form the stepped portion on the vertical axis. However, as shown in FIG. Across the 28 vertical axes,
The side walls on both sides thereof are pushed into the cup to form the step portion 30 on the vertical axis, and the slit-shaped notch 32 is formed in the step portion 30.
By forming the above, it is possible to obtain a convergence cup having the same effect as that of the above embodiment.

Further, in the above embodiment, the color cathode ray tube having no magnetic field control element magnetically coupled with the rear leakage magnetic field of the deflecting device has been described. However, the present invention is not limited to the convergence cup. It is also applicable to a color cathode ray tube in which is arranged.

[0031]

EFFECTS OF THE INVENTION In a color cathode ray tube having an electron gun for emitting three electron beams arranged in a row in which a convergence cup is attached to an electrode located on the phosphor screen side, the convergence cup is provided on the side wall. If a stepped portion is formed on the axis orthogonal to the central axis of the and the arrangement axis of the three electron beams, and a slit-shaped notch is formed on the opening side of the convergence cup at this stepped portion, the convergence cup is formed. The slit-shaped notch on the opening side prevents the reduction of the magnetic flux of the horizontal deflection rear leakage magnetic field due to the eddy current generated by the horizontal deflection rear leakage magnetic field that passes through the side wall of the convergence cup, thus increasing the horizontal deflection frequency. Even if the center beam scans due to coma, the pair of side beams scans the screen. It is possible to eliminate the green right shift where the surface shifts to the left and prevent the deterioration of the screen quality of the color cathode ray tube due to the color shift, and especially when applied to the color display tube with a high horizontal deflection frequency, the screen characteristics are improved. It can be improved and its manufacture can be facilitated.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color cathode ray tube according to an embodiment of the present invention.

2 (a) is a plan view of the convergence cup, FIG. 2 (b) is a front view, and FIG. 2 (c) is a side view.

FIG. 3 (a) is a diagram illustrating the convergence of different embodiments;
The top view of a cup, FIG.3 (b) is a front view, FIG.3 (c) is a side view.

FIG. 4 is a diagram for explaining horizontal and vertical magnetic field distributions generated by a deflection device mounted on a self-convergence in-line type color cathode ray tube.

FIG. 5 is a diagram for explaining a relationship between a scanning screen of a center beam and a scanning screen of a pair of side beams of a self-convergence in-line type color cathode ray tube.

FIG. 6 is a view showing a magnetic field control element arranged in a convergence cup of a self-convergence in-line type color cathode ray tube.

FIG. 7 is a diagram for explaining a relationship between a center-beam scanning screen and a pair of side-beam scanning screens of a self-convergence in-line type color cathode ray tube in which a magnetic field control element is arranged.

FIG. 8 is a diagram showing a waveform of a current flowing through a horizontal deflection coil of the deflection device.

9 (a) and 9 (b) are front views of a convergence cup in which a slit-shaped aperture and a relatively large aperture are formed to correct the coma aberration of the deflecting device.

[FIG. 10] Similarly, in order to correct the coma aberration of the deflecting device,
FIG. 5 is a front view of a notch formed convergence cup.

FIG. 11 is a diagram for explaining a relationship between a convergence cup having a notch and an internal conductive film.

FIG. 12 is a view for explaining the penetration of voltage from the inner surface of the neck into the convergence cup having the notch.

FIG. 13 is a view showing a structure for preventing an osmotic voltage from an inner surface of a neck with respect to the notch formed convergence cup.

[Explanation of reference numerals] 2B, 2G, 2R ... 3 electron beam 13 ... Inner conductive film 22 ... Phosphor screen 24 ... Electron gun 27 ... Deflection device 28 ... Convergence cups 29B, 29G, 29R ... Electron beam passage hole 30 ... Step Part 32 ... Slit-shaped notch

Claims (1)

[Claims] 1. An electron gun for emitting three electron beams arranged in a row, wherein a plurality of electrodes are arranged from the cathode in the phosphor screen direction, and a convergence cup is attached to the electrodes located on the phosphor screen side. In a color cathode ray tube which scans the phosphor screen by deflecting three electron beams emitted from the electron gun by horizontal and vertical deflection magnetic fields generated by a deflecting device, the convergence cup includes
A step portion is formed on the side wall on an axis orthogonal to the central axis of the cup and the arrangement axis of the three electron beams, and a slit-like cutout opening on the opening side of the convergence cup is formed in this step portion. Characteristic color cathode ray tube.