JPH09265921A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct image distortion without affecting a purity characteristic. SOLUTION: In a cathode-ray tube which is equipped with a correction means correcting the image distortion drawn on a phosphor screen by scanning of an electron beam deflected by a deflection device, the correction coils 33, 34 of the correction means are arranged in the vicinity of the deflection center of the deflection device, are formed into low impedance of 1mH or so as to be electrically independent of the deflection device, are connected to a distortion correction current supply source independent of a main deflection current supply source supplying a deflection current to the main deflection coils 30, 31 of the deflection device so as to generate an approximately uniform magnetic field by the current supplied from the distortion correction current supply source. Induced electromotive force by the interlinkage of the deflection magnetic field resulting from the magnetic coupling of first inductance element connected to a deflection main coil and second inductance element connected to the correction coil is compensated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube device such as a color picture tube device capable of correcting any image distortion.

[0002]

2. Description of the Related Art Generally, a color picture tube device deflects three electron beams emitted from an electron gun in horizontal and vertical directions by a magnetic field generated by a deflecting device, and horizontally and vertically scans a phosphor screen through a shadow mask. By doing so, a structure for displaying a color image is formed. As for such a color picture tube apparatus, at present, an in-line type color picture tube apparatus in which three electron beams emitted from an electron gun are arranged in a single row passing through the same plane is mainly used.

In such a color picture tube device, it is important to reduce image distortion (raster shape distortion) in order to improve the quality of the image displayed on the screen. The image distortion is adjusted by the distribution of the magnetic field generated by the deflecting device. However, in recent years, it has become difficult to reduce the image distortion only by the distribution of the magnetic field generated by the deflecting device due to the wider deflection angle and higher performance of the color picture tube, and the demand for the image distortion further increases the demand. ing.

As means for improving the image distortion, the purity and the convergence characteristics of this color picture tube device,
For example, Japanese Utility Model Laid-Open No. Sho 60-32871 discloses a correction coil shown in FIG. This correction coil corrects image distortion, purity, and convergence by winding 6 sets of coils 2 around 12 protrusions provided inside the annular magnetic body 1 and energizing each of the coils 2. Has become.

That is, of the six sets of coils 2, two sets of coils form two magnetic poles and a magnetic field 4 shown by a broken line by energization, as shown in FIGS. 11 (a) and 11 (b). Then, the 3 electron beam 5 is displaced in the direction of the arrow 6 to correct image distortion and purity. The other four sets of coils 2
Is energized, as shown in (c) to (f),
Convergence correction is performed by forming 4 to 6 magnetic poles and forming a magnetic field 7 shown by a broken line to displace the 3 electron beam 5 in the direction of arrow 8.

The advantage of this correction coil is that the amount of correction of image distortion and purity can be arbitrarily adjusted by supplying an appropriate current to the coil, thereby improving image distortion and purity characteristics. However, when the image distortion is corrected using this correction coil, not only the image distortion,
At the same time, there is a problem that the purity (color purity) changes.

That is, since the image distortion and the purity characteristic of the color cathode ray tube device depend on the deflection angle of the electron beam scanning the phosphor screen, for example, the phosphor screen is deflected by the magnetic field generated by the deflection device. The distortion correction in the vertical direction of the image drawn above will be described. As shown in FIG. 12, the correction magnetic field 13 generated by the correction coil 12 arranged behind the deflection device 9 is the vertical deflection magnetic field generated by the deflection device 9. Assuming a uniform magnetic field in the same direction as 10, the total amount of magnetic field contributing to vertical deflection increases, and the electron beam 5 supposed to reach the point P reaches the point P1 outside the point P. Therefore, the image distortion can be corrected. However, at the same time, since the correction coil 12 is arranged behind the deflecting device 9, the deflection center is changed from O to O1.
Then, the deflection angle of the electron beam 5 that moves backward and reaches the phosphor screen 11 becomes small, and the incident angle to the shadow mask changes, which affects the purity characteristics.

That is, with the correction coil 12, basically, image distortion can be arbitrarily corrected at each point on the screen, but at the same time, the purity characteristic is changed, and the uniformity of the screen is significantly impaired. Further, the correction of the image distortion by the correction coil 12 causes an increase in cost.

As a vertical image distortion correcting means other than the above, there is a method of finely adjusting the deflection amount by the main deflection coil itself of the deflecting device without using the special correction coil as described above.
However, in this method, since the inductance of the vertical deflection coil is too large (usually 1 mH or more for TV), high-frequency distortion correction, for example, when correcting image distortion in a partial area caused by horizontal scanning, horizontal deflection In the case of high frequency modulation of about 10 times the frequency, the load increases and the required high frequency correction voltage becomes so large that it is difficult to put into practical use.

[0010]

As described above, as a means for improving the image distortion characteristics of the color picture tube device, 6 sets of coils are wound around 12 projections provided inside the annular magnetic body. There is a correction coil that corrects image distortion, purity and convergence by energizing the coil. In this correction coil, of the 6 coils,
By energizing, two magnetic poles are formed in two sets of coils to correct image distortion and purity.

According to this correction coil, there is an advantage that the correction of the image distortion and the purity can be arbitrarily adjusted by appropriately supplying the current to the coil, whereby the image distortion and the purity can be improved. However, when the image distortion is corrected by using this correction coil, the purity changes accompanying it and the uniformity of the screen is significantly impaired. This change in the purity characteristic is a serious problem in a color picture tube having a phosphor screen in which each color phosphor layer is formed in a dot shape. Further, the above-mentioned correction coil has a problem of increasing cost.

As an image distortion correction means other than the above, there is a method of finely adjusting the deflection amount by the deflection coil itself of the deflection device without using a special correction coil as described above. However, in this method, the impedance of the deflection coil is too high,
In the case of high frequency distortion correction, there is a problem that the load increases and the necessary high frequency correction voltage becomes so large that it is difficult to put into practical use.

The present invention has been made in order to solve the above problems, and uses a correction coil to construct a cathode ray tube device capable of correcting image distortion without affecting the purity characteristics. With the goal.

[0014]

In order to solve the above-mentioned problems, the present invention is directed to a deflection device having a main deflection coil for generating a magnetic field for deflecting an electron beam emitted from an electron gun, and a deflection device deflected by this deflection device. In a cathode ray tube device having a correction coil for correcting the distortion of the image drawn on the phosphor screen by the electron beam, the correction coil is arranged near the deflection center of the deflection device and formed to have a low inductance of 1 mH or less. , A substantially uniform correction by an arbitrary distortion correction current supplied from a distortion correction current supply source independent of the main deflection current supply source that electrically supplies a deflection current to the main deflection coil independently of the main deflection coil It generates a magnetic field.

The induced electromotive force generated between the deflection main coil and the correction coil is a first inductance element connected in series with the main deflection coil and a second inductance element connected in series with the correction coil. Can be compensated by magnetically coupling.

The first inductance element and the second inductance element may be wound around the same magnetic material,
Further, it may be wound one or more times around the annular magnetic body that constitutes the closed circuit.

Further, the first inductance element or the second inductance element may be connected to a resistor or a capacitor that deforms the waveform of the induced electromotive force generated in the first or second inductance element.

Further, the distortion correction coil may have both a horizontal direction and a vertical direction, or may have one of them.

As described above, the correction coil, which is electrically independent of the deflection device and generates a substantially uniform correction magnetic field, is arranged near the deflection center of the deflection device, and the main deflection current supply source is supplied to the correction coil. By supplying a current from a distortion correction current supply source independent of, a required correction magnetic field can be generated without displacing the deflection center of the deflection device. As a result, even if the image distortion is corrected, the change in the purity characteristic can be avoided. Further, by making the correction coil have a low inductance of 1 mH or less, preferably about 100 μH, the load during current supply at high frequency is reduced, and good response is obtained at high frequency correction of about 1 MHz. Further, by generating a substantially uniform distortion correction magnetic field, deterioration of the convergence characteristic at the time of distortion correction is prevented. In addition,
In the case of a cathode ray tube used for a computer display, most of the coil load becomes an inductance component at a high frequency of about 1 MHz, and when high frequency correction is performed by a normal current supply circuit, the response deteriorates due to a transient phenomenon. Therefore, the inductance of the correction coil is preferably 100 μH or less in consideration of the followability in high frequency correction. Further, considering the correction sensitivity, the inductance of the correction coil is preferably 20 μH or more.

Further, a first inductance element is connected to the deflection device in series with the main deflection coil, and the first inductance element is connected to the correction coil.
By connecting the inductance element and the second inductance element which is magnetically coupled to each other in series, it is possible to reduce the induced electromotive force which is not preferable for the deflection of the electron beam caused by the interlinkage magnetic flux between the main deflection coil and the correction coil. it can.

Further, when the first inductance element and the second inductance element are wound around the same magnetic material or wound around an annular magnetic material forming a closed circuit one or more times, the structure of the inductance element is simplified. can do.

Furthermore, the induced electromotive force generated in the inductance element is mainly deflected by connecting the first or second inductance element to a resistor or a capacitor that deforms the waveform of the induced electromotive force generated in the first or second inductance element. Match the induced electromotive force generated in the coil,
The electromotive force compensation effect can be enhanced.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a color picture tube device which is one form thereof. The color picture tube device includes a panel 20 and a funnel-shaped funnel 2 integrally joined to the panel 20.
1 has an envelope consisting of 1, and on the inner surface of its panel 20,
3 stripes or dots that emit blue, green, and red
A phosphor screen 22 including a color phosphor layer is provided,
A shadow mask 23 is arranged inside the phosphor screen 22 so as to face the phosphor screen 22. On the other hand, funnel 2
In the neck 24 of No. 1, 3 in a row arranged on the same horizontal plane
An electron gun 25 that emits an electron beam is arranged. A deflecting device 27 is mounted on the outer side of the funnel 21 near the boundary between the large-diameter portion 26 and the neck 24, and the deflecting device 27 is further provided with a correcting means described later.

The structures of the orientation device and the correction coil are as shown in FIGS. 2 and 3. FIG. 2 is a sectional view of the deflecting device as seen from the tube axis direction, and FIG. 3 is a circuit diagram showing the relationship between the main deflecting coil and the correcting coil of the deflecting device.

As shown in FIG. 2, the deflection device 27 includes a pair of upper and lower horizontal main deflection coils 30 arranged inside a trapezoidal cylindrical mold 29, and a pair of left and right vertical main deflection coils arranged outside the mold 29. The main deflection coil 31 and a core 32 arranged outside the horizontal and vertical main deflection coils 30 and 31.
It is composed of The horizontal and vertical main deflection coils 3
In the illustrated example, 0 and 31 are saddle-wound so as to generate a pincushion-shaped magnetic field for the horizontal main deflection coil 30 and a barrel-shaped magnetic field for the vertical main deflection coil 31, and for the horizontal main deflection coil 30, The vertical main deflection coil 31 is divided into a pair of upper and lower split coils 30HT and 30HB.
It is formed in a structure divided into 1 VR.

The correction coil is a horizontal main deflection coil 30.
And a vertical distortion correction coil 34 corresponding to the vertical main deflection coil 31. The horizontal distortion correction coil 33 is a pair of upper and lower split correction coils 33 arranged at substantially the same position as the pair of upper and lower split coils 30HT and 30HB of the horizontal main deflection coil 30.
It consists of HT and 33HB. Further, the directional distortion correction coil 34 is
A pair of left and right split coils 31VL of the vertical main deflection coil 31,
It is composed of a pair of left and right split correction coils 34VL and 34VR arranged at substantially the same position as 31VR. Each distortion correction coil 3
3HT, 33HB, 34VL, 34VR are the deflection devices 2 respectively.
7 near the deflection center, that is, the horizontal distortion correction coil 3
Regarding the three division correction coils 33HT and 33HB, the deflection center thereof is near the deflection center of the horizontal main deflection coil 30, and the division correction coils 34VL and 3 of the vertical distortion correction coil 34.
For 4VR, the deflection center is the vertical main deflection coil 31.
It is located near the deflection center of. It should be noted that here, the deflection center means the tube axis direction coordinate position where the tube axis direction magnetic field distribution exhibits a peak. The split correction coils 33HT and 33HB of the horizontal distortion correction coil 33 are shown in FIG.
In addition, the division correction coils 34VL and 34VR of the vertical distortion correction coil 34 are connected as shown in FIG.
Each of the electrodes 3 and 34 is formed to have a low impedance of 1 mH or less, and generates a substantially uniform magnetic field for the three electron beams.

That is, as shown in FIG. 3A, in the horizontal main deflection coil 30 of the deflection device 27, a pair of upper and lower split coils 30HT and 30HB are connected in parallel, and the split coils 30HT and 30HB have an inductance element. 35 are connected in series and are connected to a main deflection current supply source (not shown). Further, the split correction coils 33HT and 33HB of the horizontal distortion correction coil 33 are connected in series, and further, the inductance element 36 is connected in series to the split correction coils 33HT and 33HB, so that the distortion independent of the main deflection current supply source is obtained. It is connected to a correction current source (not shown). further,
Inductance element 35 and horizontal distortion correction coil 3 connected in series to split coils 30HT and 30HB of deflection device 27.
An inductance element 36 connected in series to the three division correction coils 33HT and 33HB is configured to be magnetically coupled, and compensates an induced electromotive force between the horizontal deflection coil and the horizontal distortion correction coil. .

As shown in FIG. 3B, the vertical main deflection coil 31 of the deflecting device 27 has a pair of left and right split coils 31VL and 31VR connected in series, and the split coils 31VL and 31VR have an inductance element. 37 are connected in series, and are connected to the main deflection current supply source via the inductance element 37. A resistor 38 or a capacitor is connected in parallel with the inductance element 37. Further, the split correction coils 34VL and 34VR of the vertical distortion correction coil 34 are connected in series, and the inductance element 39 is connected in series to the split correction coils 34VL and 34VR, and the main deflection current is passed through the inductance element 39. It is connected to a distortion correction current supply source independent of the supply source. In addition, the split coil 31V of the deflection device 27
Dividing correction coils 34VL, 3 of an inductance element 37 and a vertical distortion correction coil 34 connected in series with L, 31VR
The inductance element 39 connected in series to the 4VR is configured to be magnetically coupled, and compensates the induced electromotive force between the vertical deflection coil and the vertical distortion correction coil.
The resistor 38 or the capacitor connected in parallel with the inductance element 37 has a waveform of an induced electromotive force generated in the inductance element 37, which will be described later, in the vertical main deflection coil 31.
This is to increase the compensation effect by matching the induced electromotive force waveform generated in.

The horizontal and vertical distortion correction coils 33 and 34 of such a correction coil are manufactured by forming a pair of upper and lower split coils 30HT and 30H of the horizontal main deflection coil 30 of the deflection device 27.
When the B and the pair of left and right split coils 31VL and 31VR of the vertical main deflection coil 31 are wound into the winding groove of the manufacturing jig, for example, as shown for the vertical distortion correction coil 34 in FIG. After winding the vertical main deflection coil 31 around 42A, the winding 41 is connected to the terminals 42B,
42C, and then the vertical strain correction coil 34 is wound. Finally, after winding the winding wire 41 to the terminal 42D, the winding wire 41 is cut between the terminals 42B and 42C. Then, a predetermined inductance element or the like may be connected to the portion that has become the terminal.

This manufacturing method can also be carried out by conversely starting winding from the vertical distortion correction coil and then winding the vertical main deflection coil.

In particular, such a manufacturing method is effective when the main deflection coil of the deflection device is manufactured by the slot winding type in which the winding position can be arbitrarily selected. Further, by thus winding the correction coil at the same time as the main deflection coil of the deflection device, the cost required for manufacturing the correction coil can be significantly reduced.

By the way, when the color picture tube device is constructed as described above, the image distortion can be corrected without changing the purity. That is, when the correction coil is arranged behind (neck side) the deflector as in the conventional case, the correction magnetic field is formed behind the deflection center of the deflector. Therefore, when the image distortion is corrected by the correction magnetic field, the deflection center is displaced rearward with it, and the change in purity cannot be avoided. However, in the color picture tube device of this example, since the correction coil is arranged near the deflection center of the deflection device 27, the deflection center is not displaced even if the correction magnetic field is generated, so the incident angle with respect to the shadow mask is changed. There is nothing to do. Therefore, the image distortion can be corrected without changing the purity. For example, by supplying a correction current to the pair of left and right split coils 34VL and 34VR of the vertical distortion correction coil 34, as shown in FIG.
As shown in (a) and (b), a substantially uniform correction magnetic field 4 in the same direction as the vertical deflection magnetic field 44 generated by the deflection device 27.
5, when the correction magnetic field 45 is not generated,
The three-electron beam 46 deflected to the point P on the phosphor screen 22 is deflected to the point P1 on the outer side in the vertical direction without displacing the deflection center O of the deflecting device 27, and the vertical direction without changing the purity. The image distortion of can be corrected. Similarly, the image distortion in the horizontal direction can be corrected without changing the purity by supplying a correction current to the pair of upper and lower split coils 33HT and 33HB of the horizontal distortion correction coil 33.

In this case, the split coils 33HT and 33HB of the horizontal distortion correction coil 33 of the correction coil and the split coils 34VL and 34VR of the vertical distortion correction coil 34 are the horizontal and vertical vertical main deflection coils 30 and 31 of the deflection device 27. Since it is connected to a distortion correction current supply source independent of the main deflection current supply source that supplies a current to, an arbitrary current can be supplied,
A desired image distortion correction can be performed. Moreover, the horizontal and vertical distortion correction coils 33 and 34 of the correction coil are
Since it is formed with an impedance of 1 mH or less, a good response to a high frequency can be obtained, and as shown in FIG. 6, a simple current supply circuit in which resistors 48a and 48b are connected to an amplifier 47 for amplifying a correction voltage. By the correction coil horizontal,
A wide range of image distortion correction from low frequency to high frequency can be performed by supplying a current to the vertical distortion correction coils 33 and 34 (the vertical distortion correction coil 34 is illustrated).

Further, as described above, the inductance element 35 connected in series to the split coils 30HT and 30HB of the horizontal main deflection coil 30 of the deflecting device 27, and the split coil 33HT of the horizontal distortion correction coil 33 of the correction coil, Inductance element 36 serially connected to 33HB, inductance element 37 serially connected to split coils 31VL and 31VR of vertical main deflection coil 31 of deflection device 27, and vertical distortion correction coil 34 of the correction coil. Since the split coils 34VL and 34VR are magnetically coupled to the inductance element 39 connected in series, the horizontal and vertical main deflection coils 30 and 31 of the deflection device 27 are connected.
The influence of the induced electromotive force on the deflection can be eliminated. That is, the inductance elements 35 and 3
When not providing 6, 37, 39, for example, considering the vertical main deflection coil 31, as shown in FIG.
Due to the interlinking magnetic field generated between the vertical main deflection coil and the vertical distortion correction coil, the correction current 50 flowing through the split coils 34VL and 34VR of the vertical distortion correction coil 34 corresponds to
A pulsed induced electromotive force 51 is generated between the terminals of the vertical main deflection coil 31, which may be unfavorably affected. However, as described above, the inductance elements 35, 36, 3
By providing Nos. 7 and 39, the generation of the induced electromotive force 51 can be suppressed as shown in FIG. 7B corresponding to FIG.

The above-mentioned image distortion correction will be described more concretely by taking vertical image distortion correction as an example. Vertical distortion correction coil pair of split coils 34VL, 3
4VR is formed by winding 8 turns in the same winding groove as the split coils 31VL and 31VR of the vertical main deflection coil 31 of the deflection device 27. In addition, the inductance element 3 connected in series to the split coils 31VL and 31VR of the vertical main deflection coil 31.
7 and the inductance element 39 connected in series to the split coils 34VL, 34VR of the vertical distortion correction coil 34 of the correction coil are wound around a drum-shaped ferrite core having a core diameter of 5 mm and a height of 13 mm, which will be described later, by 150 and 25 turns, respectively. ing. Although not shown, the drum-shaped ferrite core around which the inductance elements 37 and 39 are wound is arranged outside the deflecting device so as not to affect the deflection of the electron beam. The inductance of the correction coil is 30 μH in total in the split coils 34VL and 34VR, 1.6 μH in the inductance element 37, 37 mH in the inductance element 39, and the entire vertical distortion correction coil system (split coil of the vertical distortion correction coil 34 It is 70 μH for 34VL, 34VR and the inductance element 39).

With such a configuration, a vertical image distortion correction sensitivity of a little over 1 mm can be obtained for a correction current of 100 mA, so that the amount of change in the landing of the electron beam with respect to the phosphor screen is 1 μm or less. I was able to. In addition, it has become possible to correct any image distortion up to a high frequency of about 1MHz.

In the above embodiment, the inductance element connected to the horizontal main deflection coil of the deflection device, the inductance element magnetically coupled to this inductance element and connected to the horizontal distortion correction coil, and the vertical element As shown in FIG. 8, the inductance element connected to the main deflection coil and the inductance element magnetically coupled to the inductance element and connected to the vertical direction distortion correction coil are used as shown in FIG. Correction coil,
It can be formed by winding an insulated wire connected to each of the vertical main deflection coil and the vertical distortion correction coil around a drum-shaped core 54 made of a ferromagnetic material such as ferrite (the inductance element 35 in FIG. 8). , 3
6 is illustrated).

Further, as shown in FIG. 9, the insulated coil 57 connected to the main deflection coil (or the correction coil) is passed through the central portion of the annular magnetic body 55 forming the closed circuit, and the annular magnetic body 55 is corrected by the correction coil. Alternatively, the insulated electric wire 56 connected to (or the main deflection coil) may be wound one or more times. In particular, when the annular magnetic body 56 is used, the structure can be greatly simplified.

In the above embodiment, the case where the correction coil is manufactured integrally with the main deflection coil of the deflection device has been described. However, this correction coil is manufactured separately from the main deflection coil of the deflection device and then It may be attached near the deflection center of the deflection coil. Alternatively, a winding groove may be specially provided inside the deflecting device and wound in the winding groove.

[0041]

The correction coil is arranged near the deflection center of the deflection device, and the correction coil is electrically formed independently of the deflection device to have a low impedance of 1 mH or less, and a deflection current is supplied to the main deflection coil. If the structure is such that a current supplied from a distortion correction current supply source independent of the deflection current supply source generates a substantially uniform magnetic field, a required correction magnetic field can be generated without moving the deflection center of the deflection device. it can. As a result, even if the image distortion is corrected, the change in the purity characteristic can be avoided. Further, by setting the correction coil to have a low impedance of 1 mH or less, a good response to high frequencies can be obtained.

Further, the deflection device is provided with a first inductance element connected in series to the main deflection coil, and the correction coil is connected in series with a second sub-coil magnetically coupled to the first inductance element. It is possible to reduce the induced electromotive force that is not preferable for the deflection of the electron beam caused by the interlinkage magnetic flux between the deflection coil and the correction coil.

Further, by winding the first inductance element and the second inductance element around the same magnetic body or one or more times around the annular magnetic body forming a closed circuit,
The structure of the inductance element can be simplified.

Furthermore, by connecting the first or second inductance element to a resistor or a capacitor that deforms the waveform of the induced electromotive force generated in the first or second inductance element, the induced electromotive force generated in the inductance element is mainly deflected. Match the induced electromotive force generated in the coil,
It is possible to obtain the effect that the compensation effect of the electromotive force can be enhanced.

The present invention can be applied regardless of whether the phosphor screen is stripe-shaped or dot-shaped, but the dot-shaped phosphor screen is particularly effective because it has a small margin for landing deviation of the electron beam. is there.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color picture tube device that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an arrangement of a correction coil with respect to a deflecting device of the color picture tube device as viewed from the tube axis direction.

FIG. 3A is a circuit diagram showing a relationship between a horizontal main deflection coil of a deflection device and a horizontal distortion correction coil of a correction coil, and FIG. 3B is a vertical direction of a vertical main deflection coil and a correction coil. It is a circuit diagram which shows the relationship with a distortion correction coil.

FIG. 4 is a diagram for explaining a method of manufacturing a correction coil.

5 (a) and 5 (b) respectively illustrate the relationship between the magnetic field generated by the vertical main deflection coil and the correction magnetic field generated by the vertical distortion correction coil, and the change in the landing position of the electron beam. FIG.

FIG. 6 is a diagram showing a configuration of a correction current supply circuit that supplies a current to a correction coil.

FIG. 7 (a) is a diagram showing a voltage waveform generated between terminals of the vertical distortion correction coil and the vertical main deflection coil when an inductance element is not connected to the vertical distortion correction coil, FIG. 7 (b). FIG. 6 is a diagram showing a voltage waveform generated between terminals of a vertical distortion correction coil and a vertical main deflection coil when an inductance element is connected to the vertical distortion correction coil.

FIG. 8 is a diagram showing a structure of a first inductance element connected to a vertical main deflection coil and a second inductance element magnetically coupled to the first inductance element and connected to a vertical distortion correction coil.

FIG. 9 is a diagram showing a different structure of a first inductance element connected to the vertical main deflection coil and a second inductance element magnetically coupled to the first inductance element and connected to the vertical distortion correction coil. .

FIG. 10 is a diagram showing a structure of a conventional correction coil.

11 (a) to 11 (f) are diagrams for explaining a magnetic field generated by a conventional correction coil.

12 (a) and 12 (b) are diagrams for explaining problems in image distortion correction by the correction coil.

[Explanation of symbols]

 21 ... Funnel 22 ... Phosphor screen 24 ... Neck 25 ... Electron gun 26 ... Large diameter part 27 ... Deflection device 29 ... Mold 30 ... Horizontal deflection coil 30HT, 30HB ... Split coil 31 ... Vertical deflection coil 31VL, 31VR ... Split coil 32 ... core 33 ... horizontal direction distortion correction coil 33HT, 33HB ... division correction coil 34 ... vertical direction distortion correction coil 34VL, 34VR ... division correction coil 35 ... first inductance element 36 ... second inductance element 37 ... first inductance element 38 ... Resistance 39 ... 2nd inductance element 44 ... Vertical deflection magnetic field 45 ... Correction magnetic field 47 ... Amplification part 48a, 48b ... Resistor 54 ... Core 55 ... Annular magnetic body 56 ... Insulated electric wire

Claims (6)

[Claims] 1. A deflection device having a main deflection coil for generating a magnetic field for deflecting an electron beam emitted from an electron gun, and distortion of an image drawn on a phosphor screen by the electron beam deflected by the deflection device. In a cathode ray tube device having a correction coil for correction, the correction coil is arranged near a deflection center of the deflection device and is formed to have a low inductance of 1 mH or less, and the main deflection coil is electrically independent of the main deflection coil. A cathode ray tube device, which generates a substantially uniform distortion correction magnetic field by an arbitrary correction current supplied from a distortion correction current supply source independent of a main deflection current supply source which supplies a deflection current to a coil. 2. A first inductance element connected in series to the main deflection coil main deflection coil, and a second inductance element connected in series to the correction coil, wherein the first and second inductance elements are provided. 2. The cathode ray tube apparatus according to claim 1, wherein the magnetic field is magnetically coupled in a direction to compensate an induced electromotive force generated by an interlinkage magnetic flux between the main deflection coil and the correction coil. 3. The cathode ray tube device according to claim 2, wherein the first inductance element and the second inductance element are wound around the same magnetic body. 4. The cathode ray tube device according to claim 2, wherein at least one of the first inductance element and the second inductance element is wound one or more times around an annular magnetic body forming a circuit. 5. The first inductance element or the second inductance element is connected to a resistor or a capacitor that deforms the waveform of the induced electromotive force generated in the first or second inductance element. The described cathode ray tube device. 6. The deflection main coil includes a horizontal main deflection coil that generates a magnetic field that deflects the electron beam in the horizontal direction and a vertical main deflection coil that generates a magnetic field that deflects the electron beam in the vertical direction. 6. The coil comprises a horizontal distortion correction coil corresponding to the horizontal main deflection coil and a vertical distortion correction coil corresponding to the vertical main deflection coil. The described cathode ray tube device.