JPH1050235A - Cathode-ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an electron gun characteristic without providing an additional circuit, by arranging a coil in a magnetic field generated by a deflection device, and utilizing induced electromotive force, generated in the coil, for forming an electron lens. SOLUTION: In a cathode-ray tube device, a coil 25 is arranged near to a deflection device 6 on the inner side of a funnel 2. In an electron gun 20, an anode electrode GA, neighboring a focus electrode GF and positioned on a phosphor screen side is divided into three electrodes GA1, GA2, and GA3. Voltage having a waveform synchronizing with a horizontal deflection magnetic field generated by the deflection device 6 is applied to the divided electrode GA2 out of three electrodes. Consequently, an electron lens (quadrupole lens) can be formed, which has a quadrupole component (where an electron beam is converged in a vertical direction, and diverging in the horizontal direction, also strength is weakened with the increase of a deflection angle). By this way, a dynamic focus can be realized without providing a circuit, for generating dynamic voltage, on the outside.

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, and more particularly to a cathode ray tube having improved electron gun characteristics such as focus performance.

[0002]

2. Description of the Related Art At present, a color picture tube device is mainly used as a cathode ray tube device used as an image display device.
As shown in FIG. 11, this color picture tube device has an envelope composed of a panel 1 and a funnel 2, and an electron beam 5 emitted from an electron gun 4 disposed in a neck 3 of the funnel 2. Is deflected by a horizontal and vertical deflection magnetic field generated by a deflecting device 6 mounted on the outside of the funnel 2, and a phosphor screen 7 formed on the inner surface of the panel 1 is horizontally and vertically scanned to display a color image. The structure is formed. The phosphor screen 7 is
Dot or stripe 3 emitting blue, green and red
The three electron beams 5 are selected by a shadow mask 8 disposed opposite to the phosphor screen 7 so as to emit light from the corresponding three-color phosphor layers.

The magnetic field generated by the deflecting device 6 is usually
The distortion of the image is removed and the three electron beams 5 are distorted so as to be concentrated on the screen. Therefore, the electron beam 5 receives a different force depending on the location, and the beam spot on the screen has a distorted shape. This phenomenon is called deflection defocus. FIG. 12 shows the shape of the beam spot on the screen. The beam spot 10 has a substantially circular shape in the center of the screen, but a halo portion 12 having a low brightness appears in a vertical direction (Y-axis direction) of the core portion 11 having a high brightness in a peripheral portion of the screen. This is because the electron beam is over-converged in the vertical direction by the deflection magnetic field. The beam spot 10 is moved in the horizontal direction (X
The diameter in the axial direction) increases significantly.

[0004] As a result, deflection defocus deteriorates the resolution of the peripheral portion of the screen. In addition, this is a factor of generation of swell of luminance called moire generated by interference between the shadow mask and the scanning line and deteriorating image quality.

As a method of improving the image deterioration due to the deflection defocus, there is a method called a dynamic focus method. This is to supply a parabolic voltage synchronized with the deflection of the electron beam to some electrodes of the electron gun,
In this method, an electron lens whose intensity dynamically changes is formed, and mainly the halo portion 12 in the vertical direction is removed.

However, this dynamic focus method requires a dedicated circuit, and causes an increase in cost. Therefore, in practice, it can only be used for high-grade pipes. In addition, a method that does not require an additional circuit is desired for a high-grade pipe type. Further, even when the dynamic focus method is used, it is desired to lower the dynamic voltage and reduce the circuit load. However, there is a limit in reducing the dynamic focus voltage only by improving the electrode structure of the electron gun.

In the ordinary dynamic focus method, the halo portion 12 in the vertical direction at the periphery of the screen can be removed, but the problem that the diameter in the horizontal direction becomes large is not solved. It is known that in order to improve the horizontal diameter, a quadrupole lens should be formed as close as possible to the deflecting device, and if possible, the quadrupole lens changes dynamically toward the phosphor screen side from the main lens. It is effective to form a quadrupole lens. But in this case,
It is necessary to dynamically change a high voltage of about 20 kV or more, which makes practical use difficult.

In general, the application of the anode voltage to the electron gun is performed via a conductive film coated on the inner surface of the funnel, and the other voltages are applied to a stem pin provided on the stem at the neck end. Is done through However, the number of stem pins provided on the stem is fixed, and only two types of voltages can be supplied as the focus voltage when the neck diameter is 29.1 mm, and only one type when the neck diameter is 22.5 mm. Can not. If another voltage is required, a method of arranging a resistor in the neck and dividing the anode voltage or the like by the resistor is required. However, the use of the resistor not only causes an increase in cost but also causes a discharge, so it is better not to use the resistor as much as possible.

As described above, the voltage applied to the electrode of the electron gun has many restrictions, and there is a possibility that the performance can be improved by using a plurality of voltages, but it is difficult to put it to practical use.

Further, for example, Japanese Patent Application Laid-Open No. 5-74369 discloses a technique of forming a multipole lens in a funnel to reduce deflection power and correct raster distortion. However, also in this technique, supply of a voltage is a major problem, and it is difficult to put it to practical use.

[0011]

As described above, it is important for a cathode ray tube apparatus to take measures against deflection defocus, and as a method of improving image deterioration due to the deflection defocus, a dynamic focus method has conventionally been used. is there.

However, the conventional dynamic focus method requires a dedicated circuit, which leads to an increase in cost.
In this dynamic focus method, reducing the dynamic voltage is also an important issue, but there is a limit to improving the electrode structure of the electron gun alone. Also, by forming a quadrupole lens that changes dynamically on the phosphor screen side from the main lens, the horizontal diameter of the beam spot can be reduced. However, in this case, the method of supplying the voltage also becomes a problem. Practical application is difficult.

In addition to the dynamic focus,
In general, there are many restrictions on the voltage that can be used for forming an electron lens, and when a resistor is used to supply the voltage, problems such as cost and discharge occur. Further, with respect to a technology for reducing deflection power or forming a raster distortion by forming a multipole lens in a funnel, supply of a voltage becomes a problem, and practical application is difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a cathode ray tube device capable of obtaining an electron lens for improving electron gun characteristics without providing a special additional circuit. Aim.

[0015]

SUMMARY OF THE INVENTION In a cathode ray tube apparatus having an electron gun and a deflecting device for generating a magnetic field for deflecting an electron beam emitted from the electron gun, a coil is arranged in the magnetic field generated by the deflecting device. The induced electromotive force generated in the coil is used to form an electron lens.

Further, in a cathode ray tube apparatus provided with an electron gun comprising a plurality of electrodes and a deflecting device for generating a magnetic field for deflecting the electron beam emitted from the electron gun, a coil is provided in the magnetic field generated by the deflecting device. And an electron lens utilizing an induced electromotive force generated in this coil was formed by electrodes constituting an electron gun.

In a cathode ray tube apparatus provided with an electron gun disposed in a neck of a funnel and a deflecting device mounted outside the funnel and generating a magnetic field for deflecting an electron beam emitted from the electron gun, A coil was arranged in a magnetic field generated by the device, and an electron lens utilizing induced electromotive force generated in the coil was formed inside the funnel.

Further, the electron lens is formed by an induced electromotive force whose waveform has been converted.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cathode ray tube device which is one embodiment of the present invention. This cathode ray tube device is a color picture tube device and has an envelope composed of a panel 1 and a funnel 2 having a funnel shape. On the inner surface of the panel 1, a dot shape or a stripe shape emitting blue, green, and red light is provided. A phosphor screen 7 made of a three-color phosphor layer is formed, and a shadow mask 8 is arranged inside the phosphor screen 7 so as to face the phosphor screen 7. On the other hand, 3 electron beams 5 are placed in the neck 3 of the funnel 2.
Is provided. This electron gun 2
Reference numeral 0 denotes a plurality of electrodes arranged in the direction from the cathode to the phosphor screen 7, such as an electrode forming an electron beam generator together with the cathode and an electrode forming an electron lens for converging an electron beam from the electron beam generator. Have. An anode terminal 22 is provided on the large-diameter portion 21 of the funnel 2, and a conductive film 23 is formed by coating from the inner surface of the large-diameter portion 21 to the inner surface of the adjacent portion of the neck 3. The large diameter portion 21 and the neck 3 of the funnel 2
A deflecting device 6 for generating horizontal and vertical deflecting magnetic fields for deflecting the three electron beams 5 emitted from the electron gun 20 is mounted outside the vicinity of the boundary between the two.

Further, in this color picture tube device, a coil 25 is arranged inside the funnel 2 close to the deflecting device 6, that is, in the deflecting magnetic field generated by the deflecting device 6. The coil 25 is for forming an electron lens by using an induced electromotive force generated by the deflection magnetic field.

By the way, as described above, the coil 2
When 5 is arranged, an induced electromotive force is generated in the coil 25 by the magnetic flux crossing the coil 25. This induced electromotive force Vi
Where B is the magnetic flux density at the position where the coil 25 is disposed, S is the area of the coil 25 traversed by the magnetic flux, and N is the number of turns of the coil 25. Vi = NS · dB / dt. Is proportional to

Normally, the change in the deflection magnetic field is not a perfect sawtooth wave, but a so-called S-shape correction for correcting that the magnetic flux density B and the arrival position of the electron beam on the screen are not in a proportional relationship. The waveform 27 is as shown in FIG. Therefore, the induced electromotive force Vi generated in the coil 25 has a waveform 28 shown in FIG.

Generally, in order to generate a voltage synchronized with the deflection, it is necessary to provide an external additional circuit. However, if the induced electromotive force Vi is used, the voltage synchronized with the deflection can be generated without providing the additional circuit. Can be generated. Such an induced electromotive force Vi can be generated by either a horizontal or vertical deflection magnetic field, but in general, the vertical deflection magnetic field has a low frequency and generates a low voltage. In practice, it is advantageous to use a horizontal deflection magnetic field.

In order to form an electron lens using the induced electromotive force Vi, it is supplied to an electrode constituting an electron gun or an electrode specially provided inside a funnel. At this time, the induced electromotive force Vi is supplied as it is. In addition, the power is supplied after being appropriately boosted by a transformer. Further, a method of converting the waveform into a desired waveform using a waveform conversion circuit and then supplying the converted waveform can be appropriately selected.

When the electron lens is formed using the induced electromotive force Vi, the performance of the electron gun can be improved in various forms. That is, when the waveform is not converted,
An electron lens that weakens as it is deflected can be formed, and if this voltage is used well, dynamic focus can be realized. Further, if the waveform is converted so that the voltage is kept constant during the deflection period, it can be used as a practically fixed voltage and can be used for various purposes. Also, if the waveform is converted so that the voltage is increased as the deflection is increased, an electron lens which is strengthened as the deflection is increased can be formed as in the case of ordinary dynamic focus.

Hereinafter, description will be made based on embodiments.

[0028]

[Embodiment 1] FIG. 3 shows a main structure of a cathode ray tube device according to Embodiment 1. In this cathode ray tube device, a coil 25 is placed inside the funnel 2 close to the deflection device 6. The coil 25 is connected to a limiter circuit 30 that suppresses a large reverse voltage generated during a retrace period of horizontal scanning.
It is connected to the primary side of the step-up transformer 31.

On the other hand, the electron gun 20 has a focus electrode GF
The anode electrode GA located on the side of the phosphor screen adjacent to is divided into three electrodes GA1, GA2, and GA3. Of the three divided electrodes GA1, GA2, and GA3, the divided electrode GA1 located on the cathode side and the divided electrode GA3 located on the phosphor screen side have a vertical direction as shown in FIG. Three rectangular (non-circular) electron beam passage holes 33 having a major axis (in the Y-axis direction) are provided in the divided electrode GA2 located between the divided electrodes GA1 and GA3, as shown in FIG. 3), three rectangular (non-circular) electron beam passage holes 34 having a major axis in the horizontal direction (X-axis direction) are provided. The divided electrodes GA1 and GA3 are connected in a tube, and these divided electrodes GA1 and GA3 have:
An anode terminal provided at a large diameter portion of the funnel 2 (FIG. 1)
), A conductive film 2 applied and formed on the inner surface of the funnel 2
3, and an anode voltage VA is supplied via a valve spacer 36 attached to the divided electrode GA3 and pressed against the conductive film 23.

One end on the secondary side of the step-up transformer 31 is connected to the divided electrode GA3 to be supplied with the anode voltage VA, and the other end is connected to the divided electrode GA2 located in the middle, and the divided electrode GA1 is connected to the divided electrode GA1. , GA3, a voltage lower than the anode voltage VA is applied.

Although the limiter circuit 30 and the step-up transformer 31 are drawn outside the tube in FIG. 3, they are actually arranged inside the tube.

When the cathode ray tube device is constructed in this manner, a voltage V of a waveform 37 shown in FIG. 5 is applied to the divided electrode GA2 in synchronization with the horizontal deflection magnetic field generated by the deflection device 6, and the electron beam is vertically emitted. An electron lens (quadrupole lens) having a quadrupole component converging in the direction and diverging in the horizontal direction, and having a weaker intensity as the deflection angle increases, can be formed.

In order to explain the function of this electron lens,
FIG. 6 shows an optical model of an electron lens formed by the focus electrode and three divided electrodes. In this figure,
The upper part is vertical and the lower part is horizontal. FIG.
As shown in (a), when the electron beam 5 is not deflected, a quadrupole lens QL2 having a polarity opposite to that of the quadrupole lens QL1 is focused so that the beam spot at the center of the screen is focused in both the horizontal and vertical directions. The electrode GF and the split electrode GA1 are formed on the cathode side of the main lens ML. On the other hand, as shown in (b), when the electron beam 5 is deflected in the horizontal direction, the action of the horizontal deflection magnetic field on the electron beam is represented by the quadrupole lens QLD. At this time, by decreasing the intensity of the quadrupole lens QL1 corresponding to the QLD, the deflection defocus by the quadrupole lens QLD can be corrected.

Therefore, with the above configuration, dynamic focus can be realized without providing an external circuit for generating a dynamic voltage.

In the above embodiment, the anode electrode is 3
The anode electrode is divided into two electrodes.
It may be divided.

Also, the shape of the electron beam passage hole of the split electrode is not limited to a rectangular shape, and various shapes and structures are possible. For example, by providing an eave in the periphery of the electron beam passage hole, The electrodes may have a three-dimensional structure.

Also, the conventional dynamic focus and the above configuration may be used in combination. With this configuration, the dynamic voltage can be reduced, and the load on the circuit can be reduced.

[0038]

[Embodiment 2] FIG. 7 shows a main configuration of a cathode ray tube device of Embodiment 2. In this cathode ray tube device, similar to the first embodiment, the vertical axis (Y
A coil 25 is placed near the (axis). The coil 25 is connected to the primary side of the step-up transformer 31 via a waveform conversion circuit 38 including a limiter circuit for suppressing a large reverse voltage generated during a retrace period of horizontal scanning.

On the other hand, the electron gun 20 has a focus electrode G
F and the anode electrode G located on the phosphor screen side
An intermediate electrode GM is provided between A and A.

The anode electrode GA has a funnel 2
An anode terminal (see FIG. 1) provided on the large diameter portion of the anode, a conductive film 23 formed on the inner surface of the funnel 2, and a valve spacer 36 attached to the anode electrode GA and pressed against the conductive film 23 through the anode terminal Voltage is supplied.
One end on the secondary side of the step-up transformer 31 is connected to the anode electrode GA to be supplied with an anode voltage.
The other end is connected to the intermediate electrode GM.

Although the waveform conversion circuit 38 and the step-up transformer 31 are drawn outside the tube in FIG. 7, they are actually arranged inside the tube.

In this cathode ray tube device, the induced electromotive force generated in the coil 25 is converted by the waveform conversion circuit 38 during the deflection of the electron beam by the deflection device 6 so that the voltage during the deflection is substantially constant. After that, the voltage is boosted to about 5 to 10 kV by the step-up transformer 31 and supplied to the intermediate electrode GM.

Therefore, with the above-described configuration, an extended electric field type lens having a gentle potential is formed in the main lens portion without using a resistor, and the focusing performance can be improved.

[0044]

[Embodiment 3] FIG. 8 shows a main configuration of a cathode ray tube device of Embodiment 3. In this cathode ray tube device, similar to the second embodiment, the vertical axis (Y
A coil 25 is placed near the (axis). Then, it is connected to the primary side of the step-up transformer 31 via a waveform conversion circuit 38 including a limiter circuit for suppressing a large reverse voltage generated during a retrace period of horizontal scanning. In the third embodiment, the output of the induction coil is converted by the waveform conversion circuit 38 into a parabolic waveform whose voltage increases as the deflection angle increases, similarly to the conventional dynamic focus voltage.

On the other hand, in the electron gun 20, a focus electrode GF located on the cathode side of the anode electrode GA is divided into two electrodes GF1 and GF2.

The anode electrode GA has a funnel 2
An anode terminal (see FIG. 1) provided on the large diameter portion of the anode, a conductive film 23 formed on the inner surface of the funnel 2, and a valve spacer 36 attached to the anode electrode GA and pressed against the conductive film 23 through the anode terminal Voltage is supplied.
Further, a focus voltage VF is supplied to the divided electrode GF1 located on the cathode side of the focus electrode GF via a stem pin provided on a stem sealing the end of the neck 3.

Further, in this cathode ray tube device, one end on the secondary side of the step-up transformer 31 is connected to the anode electrode GA.
Divided electrode GF2 of focus electrode GF located adjacent to
And the other end is connected to the divided electrode GF1.

Although the waveform conversion circuit 38 and the step-up transformer 31 are drawn outside the tube in FIG. 8 as well, these are actually arranged inside the tube.

When the cathode ray tube device is constructed in this manner, a voltage V having a waveform 39 shown in FIG. 9 is applied to the divided electrode GF2 in synchronization with the horizontal deflection magnetic field generated by the deflecting device 6, and the two divided electrodes GF1 , GF2, an electron lens having a quadrupole component that diverges the electron beam in the vertical direction and converges in the horizontal direction can be formed. This is the same configuration as a conventional typical dynamic focus.

[0050]

Fourth Embodiment FIG. 10 shows the structure of a main part of a cathode ray tube device according to a fourth embodiment. In this cathode ray tube device, the conductive film 23 on the inner surface of the funnel 2 at the mounting position of the deflecting device is insulated from the conductive film 23a connected to the anode terminal and the conductive film 23a. And a conductive film 23b formed by coating.

For such a conductive film 23, the coil 2
Reference numeral 5 denotes a vertical axis (inside of the funnel 2) which is close to the deflecting device so that the electron beam from the electron gun does not impinge, and which generates an induced electromotive force effectively by the horizontal deflecting magnetic field generated by the deflecting device. (Y axis) and is located close to the conductive film 23b. One end of the coil 25 is connected to the conductive film 23a, and the other end is connected to the conductive film 23a.
Connected to b.

In this cathode ray tube device, with the above configuration,
An electron lens having a quadrupole component that diverges the electron beam in the horizontal direction is formed inside the funnel 2 using the conductive film 23b as an electrode. The horizontal deflection power can be reduced by assisting horizontal deflection.

Although the present invention has been specifically described with respect to the four embodiments, the present invention can have various other configurations.

The size, shape, number of turns, and position of the coil are determined by the required voltage and deflection frequency.
It may be determined as appropriate from the specifications of the transformer.

In each of the above embodiments, one coil is used, but it is optional to provide a plurality of coils.

It is also optional to provide an intermediate terminal in the transformer to extract a plurality of different voltages.

In each of the above embodiments, the coil, the waveform conversion circuit, and the like are arranged inside the tube. However, these may be arranged outside the tube, and a required voltage may be supplied via the stem pin.

[0058]

In a cathode ray tube device having an electron gun and a deflecting device, a coil is arranged in a magnetic field generated by the deflecting device, and an electron lens utilizing induced electromotive force generated in the coil is formed. Specifically, when an electron lens utilizing an induced electromotive force generated in the coil is formed inside an electrode or a funnel constituting an electron gun, a deflection device is provided without providing an additional circuit outside as in the related art. The focus can be dynamically corrected. In addition, since a voltage that changes based on the anode voltage can be generated, an electron lens that dynamically changes can be formed closer to the phosphor screen than the main lens. In addition, by using together with normal dynamic focus, the dynamic voltage can be reduced. Further, since various potentials can be generated without using a resistor, for example, an extended electric field type lens and other additional lenses can be formed. Further, for example, it is possible to form a multipole lens in the funnel to reduce the deflection power, and so on.

[Brief description of the drawings]

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

FIG. 2A is a waveform chart showing a change in a deflection magnetic field, and FIG. 2B is a waveform chart of an induced electromotive force generated in a coil arranged in the deflection magnetic field.

FIG. 3 is a diagram showing a main configuration of Example 1 according to one embodiment of the present invention.

FIGS. 4A and 4B are diagrams showing the shapes of electron beam passage holes of the divided anode electrodes constituting the electron gun according to the first embodiment.

FIG. 5 is a waveform diagram of a voltage supplied to the divided anode electrodes.

FIGS. 6A and 6B are diagrams for explaining an electron lens formed in the electron gun according to the first embodiment.

FIG. 7 is a diagram illustrating a main configuration of Example 2 according to an embodiment of the present invention.

FIG. 8 is a diagram showing a main part configuration of a third embodiment according to the embodiment of the present invention.

FIG. 9 is a waveform diagram of a voltage supplied to divided focus electrodes of the electron gun according to the third embodiment.

FIG. 10 is a diagram showing a main part configuration of Example 4 according to an embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a conventional color picture tube device.

FIG. 12 is a diagram showing a shape of a beam spot on a screen in a conventional color picture tube device.

[Explanation of symbols]

 2 Funnel 6 Deflecting device 7 Phosphor screen 20 Electron gun 23 Conductive film 23a, 23b Divided conductive film 25 Coil 30 Limiter circuit 31 Step-up transformer 38 Waveform conversion circuit GA Anode electrode GA1 , GA2, GA3 ... divided electrodes of anode electrodes GF ... focus electrodes GF1, GF2 ... divided electrodes of focus electrodes ML ... main lenses QL1, QL2 ... quadrupole lenses QLD ... quadrupole lenses

Claims (4)

[Claims] 1. A cathode ray tube device comprising an electron gun and a deflecting device for generating a magnetic field for deflecting an electron beam emitted from the electron gun, wherein a coil is arranged in the magnetic field generated by the deflecting device. A cathode ray tube device wherein an induced electromotive force generated in a coil is used for forming an electron lens. 2. A cathode ray tube device comprising: an electron gun composed of a plurality of electrodes; and a deflecting device that generates a magnetic field for deflecting an electron beam emitted from the electron gun. A cathode ray tube device, wherein a coil is disposed, and an electron lens utilizing an induced electromotive force generated in the coil is formed in a part of the electron gun. 3. A cathode ray tube device comprising: an electron gun disposed in a neck of a funnel; and a deflection device mounted outside the funnel and generating a magnetic field for deflecting an electron beam emitted from the electron gun. A cathode ray tube device, wherein a coil is arranged in a magnetic field generated by the deflection device, and an electron lens is formed inside the funnel by using an induced electromotive force generated in the coil. 4. The cathode ray tube device according to claim 1, wherein the electron lens is formed by an induced electromotive force whose waveform has been converted.