JP3498383B2 - Dynamic convergence device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic convergence device provided for a color cathode ray tube.

[0002]

2. Description of the Related Art For example, in an in-line three-beam type color cathode ray tube, when the deflection magnetic field of the deflection yoke is a uniform magnetic field, vertical bow-shaped misconvergence pattern distortion occurs on the screen of the color cathode ray tube as shown in FIG. Occurs. In addition, G shows a pattern by a central beam, that is, a green electron beam, and R and B show patterns by a double-sided beam, that is, a red, blue electron beam. Therefore, in many cases, dynamic convergence is performed by applying a large distortion (barrel magnetic field, pinction magnetic field) that can cancel the pattern distortion to the deflection magnetic field of the deflection yoke. However, in this case, there are drawbacks that the spot of the electron beam is distorted and the focus is deteriorated in the peripheral portion of the screen of the color cathode ray tube.

As a countermeasure, it is also possible to leave the deflection magnetic field of the deflection yoke as a uniform magnetic field, provide a quadrupole coil in the subsequent stage of the deflection yoke, and pass a convergence current through it. However, even in this case, since the deflection magnetic field is still distorted, the spot distortion of the electron beam in the peripheral portion of the screen of the color cathode ray tube cannot be completely removed, and the electron beam is applied to the quadrupole coil. Since the current is controlled,
It is not suitable for a multi-scan monitor, and it has a drawback that it is difficult to finely control the waveform and it is difficult to finely adjust the convergence in a small area of the screen.

As a special application, there is also adopted a method of supplying a convergence voltage modulated by an external transformer to a convergence plate of an electron gun through a coaxial cable. Although this method improves the convergence in the peripheral portion of the screen of the color cathode ray tube, it is expensive because a high-voltage transformer is required, and it is difficult to apply it to a consumer color image receiver.

Therefore, four electrode plates are used as the convergence electrode plates in the color cathode ray tube, and a high resistor is connected between the pair of inner electrode plates and the pair of outer electrode plates to connect the tube body of the color cathode ray tube. Provide a conductive layer on the inner and outer surfaces,
A clamp-type dynamic convergence device has been proposed in which a capacitor is formed and a convergence voltage is applied from the outside to the inside of the tube through the capacitor.

A dynamic convergence device according to such a conventional technique will be described below with reference to the drawings. FIG. 12 shows a partial sectional structure of a basic clamp system. FIG. 13 shows an equivalent circuit thereof. 12 and 13 are applied to an in-line three-beam type color cathode ray tube, and four electrode plates are used as convergence electrode plates. That is, a pair of high voltage side electrode plates 1 and 2 facing each other, and a pair of low voltage side electrode plates 3 arranged on both outer sides of the pair of high voltage side electrode plates 1 and 2 so as to face the pair of high voltage side electrode plates 1 and 2.
4 through which the central electron beam (green electron beam) passes between the pair of high voltage side electrode plates 1 and 2,
And a pair of low voltage side electrode plates 3 and 4 are horizontally arranged inside the tube body 6 of the color CRT so that electron beams (red and blue electron beams) on both sides pass therethrough.

In a parallel circuit of a high resistor R of about several tens of MΩ and a diode D having a reverse breakdown voltage of about 1 kV or more, a cathode of the diode D has a pair of high voltage side electrode plates 1 and 2 and an anode has a pair of low voltage side electrode plates 3. , 4 are connected. In this case, the high resistor R is welded onto the low voltage side electrode plate 3. The diode D is mounted on the low voltage side electrode plate 4.

Further, an insulating gap 1 is formed on a part of the inner conductive layer 16.
6 g is provided, and a portion of about 20 to 30 mm on the neck side is separated to form the inner conductive layer 7A, and the tubular body 6 is opposed to the inner conductive layer 7A.
An outer conductive layer 7B is deposited on the outer side of, and a cylindrical capacitor C having the portion (glass) of the tubular body 6 therebetween as a dielectric is formed. The low voltage side electrode plates 3 and 4 are connected to the inner conductive layer 7A of the capacitor C via the elastic conductive pieces 34.
Then, the convergence correction voltage e _c1 is applied from the convergence correction voltage signal generation source 36 of the outer conductive layer 7B of the capacitor C.

Consider the equivalent circuit of FIG. The convergence correction voltage e _c1 is a convergence correction waveform obtained by amplitude-modulating a horizontal period parabolic wave with a vertical period parabolic wave, and is a capacitor C composed of glass and electrodes.
And a high voltage (also called high voltage DC voltage) HV is clamped by a clamp circuit composed of a diode D and a resistor R,
It is supplied to the low voltage side electrode plates 3 and 4. As a result, the convergence correction voltage e _C2 is applied between the high and low voltage side electrode plates 1-3 and 2-4.
(FIG. 13) is applied.

[0010]

However, the conventional dynamic convergence device configured as described above has the following drawbacks. That is, when the high-voltage HV does not have a stabilizing circuit like a consumer color television receiver, the high-voltage HV changes abruptly depending on the picture pattern (luminance change) of the image received on the screen, and the clamp operation is appropriate. However, there is a problem that a convergence error occurs during this period.

Consider this problem with reference also to FIGS. The image on the screen 51, which is the image received, is
To make it easier to understand this problem, the stripe-shaped image pattern is “dark” at the upper and lower parts of the screen and “bright” at the center of the screen in the middle.

FIG. 10A shows the waveform of the video signal VIDEO corresponding to the video pattern on the screen 51. The luminance level of the video signal VIDEO is low level in the "dark" part of the image and high level in the "bright" part of the image. Reference numeral 1H in FIG. 10A represents one horizontal period.

FIG. 10B shows a waveform of the high voltage HV which changes corresponding to the video signal and a waveform of the convergence correction voltage e _c2 at which the peak of the clamp pulse CP is clamped at the high voltage HV.

FIG. 10C shows a part of the waveform of the convergence correction voltage e _c1 output from the convergence correction signal generation source 36.

During the falling period T1 of the high voltage HV after the image on the screen 51 has changed from the "dark" state at the top of the screen to the "bright" state at the center of the screen, the capacitor C in FIG. Current flows, and the peak of the waveform of the convergence correction voltage e _C2 drops with the time constant τ _HVD.
Clamped to. On the other hand, in the rising period T2 of the high voltage HV after the image on the screen 51 changes from the "bright" state at the center of the screen to the "dark" state at the bottom of the screen again, the diode D is biased in the reverse direction. . Therefore, the current path becomes a path for charging the capacitor C through the high resistor R. If the time constant at this time is τ ₁ , then τ ₁ = C · R. This time constant τ ₁ cannot be set too short because it is necessary to increase the waveform transmission efficiency of the convergence correction voltage e _c2 and reach the sag. Therefore, the time constant τ ₁ becomes larger than the rising time constant τ _HVU of the high voltage HV. As a result, as shown in FIG. 10B, the peak value of the waveform of the convergence correction voltage e _c2 cannot be clamped to the high voltage HV during the rising period T2 of the high voltage HV, and the high voltage HV of the convergence correction voltage e _c2 becomes impossible.
The followability with respect to is deteriorated and a convergence error occurs.

In order to avoid this problem, in other words, the problem that the voltage changes of the high voltage side electrode plates 1 and 2 and the low voltage side electrode plates 3 and 4 are the same and do not follow, a clamping method shown in FIG. 14 is also proposed. There is. This system is composed of a pair of clamp circuits, and is composed of a capacitor C ₁₂ , a diode D ₁₂ and a resistor R _{12 as} shown in FIG. 13 (corresponding to the capacitor C1, diode D1 and resistor R1 in the example of FIG. 14). Clamp circuit having the same configuration as the above (1) is provided in parallel with the inner electrode plates (high-voltage side electrode plates) 1 and 2 of the convergence electrode plate. As a result, the time constant τ _{1 of the} inner electrode plates 1 and 2 as well as the outer electrode plates 3 and 4 against the rapid change in the high voltage HV is increased.
Time constant τ ₁₂ (C12 ・ R12) similar to (C1 ・ R1)
The inner and outer electrode plates 1-
It is intended to eliminate the convergence error by simultaneously changing 2, 3 and 4 with the same time constant.

However, even in this case, as shown in FIG. 15, for example, the voltage that shifts from the "bright" state at the center of the screen to the "dark" state below it is the inner electrode plates 1 and 2 and the outer electrode plate 3. , 4 are deviated by the signal amplitude of the convergence correction voltage e _C1 , so if the time constants are combined (τ ₁₂ = τ
₁ ) The potential relationship between the inner and outer electrode plates 1-2, 3-4 is not constant, and a convergence error occurs as can be seen from the waveform difference between the convergence correction voltage e _C2 and the convergence correction voltage e _C3 . For this reason, it is necessary to shift the time constants τ ₁ and τ ₁₂ in the respective clamp circuits. However, since the difference between the time constants is highly sensitive to the convergence error,
There has been the complexity that fine adjustment is required for variations in the elements.

[0018]

The first invention is, for example,
As shown in FIG. 2, a pair of high voltage side electrode plates 1 and 2 facing each other and a pair of low voltage side electrode plates 3 arranged on both outer sides of the pair of high voltage side electrode plates 1 and 2 so as to face each other. 4, the central electron beam passes between the pair of high-voltage side electrode plates 1 and 2, and the double-sided electron beam passes between the pair of high-voltage side electrode plates and the pair of low-voltage side electrode plates (between 1, 3 and 2, 4). Are arranged horizontally inside the tube body of the color cathode ray tube so that the anode side ends of this first diode D1 of the parallel circuit of the first high resistor R1 and the first diode D1 are paired with a low voltage. The second electrode is commonly connected to the side electrode plates 3 and 4, the cathode side end is commonly connected to the pair of high voltage side electrode plates 1 and 2, and the cathode side is connected to the pair of low voltage side electrode plates 3 and 4. The anode side of the diode D2 and one end of the second high resistor R2 are commonly connected, and The other end of the high resistor R2 of 2 is connected to the pair of high voltage side electrode plates 1 and 2, and the high voltage DC voltage HV is applied to the pair of high voltage side electrode plates 1 and 2, and the parabolic wave of the horizontal period is the vertical period. Modulated voltage (convergence correction voltage) obtained by amplitude modulation by the parabolic wave of
e _c1 is supplied to the pair of low voltage side electrode plates 3 and 4 through the first capacitor C1, and a horizontal period pulse signal e _c4 is supplied to the second diode D2 through the second capacitor C2.
To the anode side of the first capacitor C1 and the first high resistance R1 and the time constant τ ₁ (C1 · R1) is the second
Is selected so that it is larger than the time constant τ ₂ (C2 · R2) by the capacitor C2 and the second high resistor R2 (τ ₁ > τ ₂ ).

The second aspect of the present invention is, for example, as shown in FIG. 6, a pair of high voltage side electrode plates 1 and 2 facing each other, and a pair of high voltage side electrode plates 1 and 2 facing each other so as to face each other. The central electron beam passes between the pair of low voltage side electrode plates 3 and 4, and the both side electron beams pass between the pair of high voltage side electrode plates 1 and 2 and the pair of low voltage side electrode plates 3 and 4. The color cathode ray tube is arranged horizontally inside the tube body to form a parallel circuit of the first high resistor R21 and the first diode D21, and the anode side ends of the first diode D21 of the parallel circuit are paired. Commonly connected to the high-voltage side electrode plates 1 and 2, the cathode side is connected to the high-voltage power supply HV, and the anode side is the first
Is connected to the cathode side of the second diode D22, the anode side of the second diode D22 is commonly connected to the high voltage side electrode plates 1 and 2, and the second diode D22 is also connected to the high voltage side electrode plates 1 and 2. A second high resistor R22 is connected between the anode side of the and the high-voltage power supply HV, and a modulated voltage (convergence correction voltage) e _{c 11} obtained by amplitude-modulating the horizontal-period parabolic wave by the vertical-period parabolic wave. Is supplied to the anode side of the second diode D22 through the second capacitor C22.

In this case, the first capacitor C21
And the time constant τ ₂₁ (C21
R21) is a second capacitor C22 and a second high resistor R
It is selected so that it is larger than the time constant τ ₂₂ (C22 · R22) according to ₂₂ (τ ₂₁ > τ ₂₂ ).

[0021]

According to the first aspect of the invention, as shown in FIGS. 2 to 4, the high-voltage HV has a downward fluctuation corresponding to a change in brightness from dark to bright on the screen of the color cathode ray tube, and bright to dark. The stable clamping operation of the convergence correction voltage e _C5 is performed with respect to the change of the rising fluctuation of the high voltage HV corresponding to the change to That is, when descending, the clamp circuit (C1, R1, D
1) the convergence correction voltage e _c5 follows the fluctuation of the high voltage HV, and when it rises, the capacitor C1 is charged in the path of the resistor R2, the diode D2 and the capacitor C1 in the horizontal retrace section, and the resistor R1 in the horizontal trace section. , The convergence correction voltage e _C5 follows the fluctuation of the high voltage HV with the time constant of the capacitor C1. In this way
The voltage of the low voltage side electrode plates 3 and 4 to which the convergence correction voltage e _C5 is applied follows the fluctuation of the high voltage HV applied to the high voltage side electrode plates 1 and 2.

Further, according to the second invention, as shown in FIGS.
As you can see on the screen of the color cathode ray tube
Fluctuation of high voltage HV corresponding to the change to
To the change of the high voltage HV rise fluctuation corresponding to the change to
Convergence correction signal e_{C 12}-E_{C 13}Follows, high pressure
Good convergence correction that does not depend on fluctuations can be performed. Immediately
When descending, the clamp circuit (C22, D22, D2
1, R22) is applied to the low voltage side electrode plates 3, 4
Convergence correction voltage e_{C 12}Follows changes in high voltage HV
And the signal e induced on the high voltage side electrode plates 1 and 2_{C 13}
The peak potential of the
The correction signal e is applied between the plates 1 and 3 and between the plates 2 and 4. _{C 12}-E_{C 13}of
An electric potential is supplied. Also, when rising, the high voltage HV rises
The potential e of the high voltage side electrode plates 1 and 2_{C 13}And low voltage side
Potential e of electrode plates 3 and 4_{C 12}But capacitor C2
2 and time constant τ due to high resistance R22_{twenty two}And capacitor C21
And time constant τ due to high resistance R21_{twenty one}Rises slowly at high
Convergence correction signal e corresponding to the fluctuation of pressure HV_{C 12}
-E_{C 13}Follows, and is a good converter that does not depend on high pressure fluctuations.
You can correct the presence.

In this case, the first capacitor C21 and the first capacitor C21
Time constant τ due to the high resistor R21 of _{twenty one}(C21 / R2
1) is the second capacitor C22 and the second high resistor R22
Time constant τ due to_{twenty two}Greater than (C22 ・ R22) (τ
_{twenty one}> Τ_{twenty two}), The horizontal retrace interval
The diode D22 becomes conductive and the diode D22
Current i22 flows to capacitor C21, and signal e_{C 12}Horizontal
Retrace section and signal e _{C 13}And the horizontal retrace interval of
While matching, gently follow the fluctuation of the high voltage HV,
Good convergence correction that does not depend on fluctuations can be performed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. In the drawings referred to below, parts corresponding to those shown in FIGS. 12 to 14 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a partial sectional structure of the first embodiment. FIG. 2 shows an equivalent circuit of the first embodiment.
In this embodiment, the present invention is applied to an in-line three-beam type color cathode ray tube.

Also in this embodiment, four electrode plates which are usually used as the convergence electrode plate (convergence plate) 55 in Trinitron (registered trademark) are used in place of the component called the convergence cup. That is, a pair of high-voltage side electrode plates 1 and 2 forming the convergence plate 55 and a pair of low-voltage side electrode plates 3 arranged on both outer sides of the pair of high-voltage side electrode plates 1 and 2 so as to face each other. , 4, and the central electron beam passes between the pair of high-voltage side electrode plates 1 and 2, and the both-side electron beams pass between the pair of high-voltage side electrode plates 1 and 2 and the pair of low-voltage side electrode plates 3 and 4. As described above, the color cathode ray tubes are horizontally arranged inside the tube body 6.

The anode side of the diode D1 of the parallel circuit of the high resistor R1 and the diode D1 is connected to the pair of low voltage side electrode plates 3 and 4, and the cathode side of the diode D1 is connected to the high voltage side electrode plates 1 and 2. . Further, one end of the diode D1 on the anode side is connected to the cathode side of the diode D2, the anode side of the diode D2 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the high voltage side electrode plates 1 and 2. To do. The resistor R1 and the resistor R2 are integrally formed on the resistor R.

The pair of low voltage side electrode plates 3 and 4 are elastic conductive pieces 3.
4 to the inner conductive layer 7A. Inner conductive layer 7
The capacitor C1 is formed by using A, the outer conductive layer 7B attached to the outside of the tube body 6, and the portion (glass) of the tube body 6 between them as a dielectric. Outside conductive layer 7B of capacitor C1
A convergence correction voltage e _c1 is applied from the convergence correction voltage signal generation source 36 to.

Further, another independent capacitor C is provided at a position different from the capacitor C1 (for example, a position opposite to the tube).
2 (which has the same configuration as the capacitor C1 and has the same dimensions as the capacitor C1 and the same capacitance value in consideration of easiness of production) is formed by using the tubular body 6. The anode side of the diode D2 is connected to the inner conductive layer 7D of the capacitor C2 via the floating electrode 52 and the elastic conductive piece 53. A horizontal output pulse e _c4 from a deflection yoke (not shown) is applied to the outer conductive layer 7C of the capacitor C2.
Is supplied. From this meaning, the deflection yoke is drawn as the horizontal output pulse generation source 37 in FIG.

The internal electrodes such as the convergence plate 55 are held by a pair of bead glasses 54 arranged in the arrow Y direction (vertical direction). In addition, in FIG.
The arrow X direction represents (horizontal direction).

Next, how the above-mentioned clamp error (convergence error) is resolved when the high voltage HV changes abruptly in the configuration shown in FIGS. 1 and 2 will be described.

On the screen 51 shown in FIG. 9, "dark" at the top of the screen
From the center to the "bright" state in the center, the video signal VI
On DEO, it changes as shown in FIG. 3A. Therefore, the high voltage HV decreases with a certain time constant τ _{HVD as} shown in FIG. 3B. At this time, as the high voltage HV decreases, a current i1 shown by a broken line arrow flows from the capacitor C1 in FIG. 2 through the diode D1, and the peak potential of the convergence correction voltage e _c5 follows and drops while being clamped to the high voltage HV. To do. At the same time, the electric charge from the capacitor C2 also flows to the high voltage HV through the diodes D2 and D1, so that the peak of the horizontal output pulse e _c6 is also clamped to the high voltage HV and drops.

After that, when the state changes from "bright" at the center of the screen to "dark" at the bottom, the high voltage HV rises with a time constant τ _HVU . In FIG. 2, as the high voltage HV rises, a current i2 indicated by a broken line arrow in the path from the resistor R2 to the diode D2 and a current i3 indicated by a broken line arrow in the path from the resistor R2 to the capacitor C2 flow to the capacitors C2 and C1.
A charge is stored in. At this time, the values of the resistor R2 and the capacitor C2 are made small, and the time constant τ ₂ (C2 · R2) is made sufficiently small compared to the time constant τ _HVU , so that the capacitor C1 can be rapidly changed in the horizontal retrace (return line) section. Is charged to follow the rise of the voltage HV.

The operation at this time will be described in more detail with reference to FIG. The peaks of the waveform of the horizontal output pulse e _{c6 and} the waveform of the convergence correction voltage e _c5 are respectively capacitor C2, diode D2, resistor R2, and capacitor C2.
In each of the clamp circuits constituted by 1, the diode D1 and the resistor R1, their horizontal retrace sections are clamped to the high voltage HV.

At this time, since the values of the resistors R1 and R2 of these two types of clamp circuits are selected as R2 << R1, the time constant τ ₂ (R2 · C2) on the horizontal output pulse e _c6 side and the convergence correction. Time constant of voltage e _c5 side τ ₁ (R1 ・ C1)
Then, there is a relation of τ ₂ << τ ₁ . Therefore, the sag of the horizontal output pulse e _c6 in FIG.
_{This is because 2} (R2 · C2) is short. However, the waveform size (amplitude) is e _{c6 in the} horizontal trace (video display) section.
Since <e _c5 , the diode D2 is reverse biased, and the convergence correction voltage e _c5 has a long time constant τ ₁
The voltage is clamped to the high voltage HV at (R1 · C1), and the waveform of the convergence correction voltage e _C5 is accurately transmitted to the high voltage HV as shown in the waveform of the convergence correction voltage e _c5 in FIG.

By the above-mentioned operation, the convergence correction voltage e _c5 can be accurately transmitted to the high voltage HV and can be transmitted to the outer electrode plates (high voltage side electrode plates) 3 and 4, and the convergence error does not occur. It is possible to perform various convergence corrections.

Further, in the above embodiment, the capacitors C1 and C2 having the conductive layers 7A to 7D formed on the inner and outer surfaces of the tubular body 6 are used, and the convergence correction voltage e _C5 and the horizontal output pulse e _{C6 are used.}
Is clamped to the high voltage HV via these capacitors C1 and C2. Therefore, the convergence correction circuit of the example of FIG. 2 including the convergence correction signal generation source 36 and the horizontal output pulse generation source 37 can be configured by a transistor circuit without using a transformer, so that a large voltage resistance capacitor such as a transformer or a discrete component can be obtained. It is possible to realize an inexpensive circuit configuration that does not require the use of shaped parts.

Next, referring to FIGS. 5 to 8, the second embodiment of the present invention will be described.
An example will be described. Also in the second embodiment, parts corresponding to those shown in FIGS. 12 to 14 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a partial sectional structure of the second embodiment. FIG. 2 shows an equivalent circuit of the second embodiment.
In this embodiment, the present invention is applied to an in-line three-beam type color cathode ray tube.

Also in this embodiment, four electrode plates which are usually used as the convergence electrode plate (convergence plate) 55 in Trinitron (registered trademark) are used instead of the component called the convergence cup. That is, a pair of high-voltage side electrode plates 1 and 2 forming the convergence plate 55 and a pair of low-voltage side electrode plates 3 arranged on both outer sides of the pair of high-voltage side electrode plates 1 and 2 so as to face each other. , 4, and the central electron beam passes between the pair of high-voltage side electrode plates 1 and 2, and the both-side electron beams pass between the pair of high-voltage side electrode plates 1 and 2 and the pair of low-voltage side electrode plates 3 and 4. As described above, the color cathode ray tubes are horizontally arranged inside the tube body 6.

Then, the high resistor R21 and the diode D2
The anode side of the diode D21 constituting the parallel circuit of 1 is connected to the pair of high voltage side electrode plates 1 and 2, and the cathode side of the diode D21 is connected to the high voltage power supply HV.
Further, the cathode of the diode D21 is connected to the pair of low voltage side electrode plates 3 and 4 through the high resistance R22. Further, the anode side end of the diode D21 is connected to the cathode side of the diode D22, and the anode side of the diode D22 is connected to the low voltage side electrode plates 3 and 4.

The pair of low-voltage side electrode plates 3 and 4 are connected to the inner conductive layer 7A through the elastic conductive pieces 34a, and the inner conductive layer 7A is formed by coating the outer conductive layer 7B on the outer side of the tubular body 6. ,
A capacitor C22 having a portion (glass) of the tubular body 6 therebetween as a dielectric is formed. Then, the convergence correction voltage signal generating source 3 is formed on the outer conductive layer 7B of the capacitor C22.
The convergence correction voltage e _{c 11} is applied from 6a. The convergence correction voltage e _{c 11} output from the convergence correction voltage signal generation source 36a is a modulated voltage obtained by amplitude-modulating a horizontal period parabolic wave with a vertical period parabolic wave.

Further, another independent capacitor C21 is formed by using a tube at a position different from the capacitor C22 (for example, a position on the opposite side of the tube). That is, the diode D
The anode side of 21 is connected to the inner conductive layer 7D via the elastic conductive piece 34b, and the inner conductive layer 7D has the outer conductive layer 7C adhered to the outer side of the tubular body 6, and the portion of the tubular body 6 between them (glass). To form a capacitor C21. The outer conductive layer 7C of the capacitor C21 is grounded.

With the above structure, in operation, the low-voltage side electrode plate and the high-voltage side electrode plate of the convergence plate are applied to the low-voltage side electrode plates 3 and 4 by the capacitance between the opposing electrode plates (between 1 and 3 and 2 and 4). Convergence correction voltage signal e _{c 12}
Is induced in the electrode plates 1 and 2 on the high voltage side, and its signal component e _{c 13}
Is determined by the capacitance division between the counter electrode plate capacitance and the glass capacitor C21. Therefore, the correction signal output from the convergence correction voltage signal generation source 36a is clamped to the high voltage HV by the glass capacitor C22, the diodes D22 and D21, and the high resistance R22, and at the same time, the signal induced on the high voltage side electrode plates 1 and 2. e _{c 13 is} also a diode D
It is clamped to the high voltage HV by 21. Effective convergence correction voltage is a voltage e _{c 12} -e _{c 13} which is applied between the high voltage side electrode plates 1, 2 and the low-voltage side electrode plates 3 and 4.

Next, with the configuration of this embodiment, the high voltage DC voltage H
A description will be given of how the above-mentioned clamp error is resolved when V changes abruptly. When the screen 51 shown in FIG. 9 changes from the “dark” state at the top of the screen to the “bright” state at the middle portion, the high voltage HV decreases with a certain time constant as shown in FIG. 7B. At this time, in FIG. 6, the signal voltage e _{c 12} applied to the low voltage electrode plates 3 and 4 according to the decrease of the high voltage HV is a current i21 shown by a broken line arrow in the path from the capacitor C22 to the diodes D22 and D21, and e _{c 12 The 12} peak potentials follow and fall while being clamped to the high voltage HV. At the same time, the signal e _{c 13} induced in the high voltage side electrode plates 1 and 2 also passes through the diode D21 and the capacitance between the electrode plates and the capacitor C21.
Of electric current flows to the high-voltage power supply HV, and the peak of the signal e _{c 13} is also clamped to the high-voltage HV and falls. As a result, the correction signal e is applied between the electrode plates (between the electrode plates 1 and 3 and between the electrode plates 2 and 4).
potential of _{c 12} -e _{c 13} is supplied.

After that, the central part of the screen "bright" to the lower part "dark"
When changing to the state of, the high voltage HV has a time constant τ _HV (B in FIG. 7).
Rise). In FIG. 6, as the high voltage HV rises, the potential e _{c 13} of the high voltage side electrode plates 1 and 2 and the low voltage electrode plate 3,
4 of potential e _{c 12} are each a capacitor C22 and the constant tau ₂₂ when due to the high resistance R22, slowly increases in time constant tau ₂₁ by high resistance and capacitor C21 R21.

At this time, by setting τ ₂₁ > τ ₂₂ , the potential rise of e _{c 12} is faster than the potential rise of e _{c 13} , so that the diode D22 conducts in the pulse section of the horizontal retrace portion and the diode D22 transfers to the capacitor C21. The current i22 flows.
As a result, the horizontal retrace portion of e _{c 12 and} the horizontal retrace portion of e _{c 13} are made to coincide with each other and gradually follow the high-voltage power supply HV. Therefore, the potentials of the correction signals e _{c 12} -e _{c 13} are still supplied between the electrode plates (between the electrode plates 1 and 3 and between the electrode plates 2 and 4), and good convergence correction is possible regardless of high voltage fluctuations. Becomes

[0048]

As described above, according to the present invention, the high-voltage DC voltage fluctuates and changes from bright to dark corresponding to the change in brightness from dark to bright on the screen of the color cathode ray tube. It is possible to achieve the effect that the convergence correction voltage can be stably clamped with respect to the change in the rising fluctuation of the high voltage corresponding to.

Therefore, even when the present invention is applied to a television receiver for consumer use in which the high-voltage DC voltage fluctuates significantly, good convergence correction characteristics can be maintained.

Further, the distortion of the electron beam spot in the periphery of the screen of the color cathode ray tube to which the present invention is applied is reduced, the focusing becomes good, and further, the dynamic focusing required for the focusing in the periphery of the screen of the electron beam. There is also a secondary effect that the voltage is small and fine adjustment for convergence becomes easy.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a color CRT showing a first embodiment of the present invention, where A is a Y cross section near a convergence plate, B is a view from the opposite side of A, and C is near a convergence plate. Figure showing X section of

FIG. 2 is a circuit diagram showing an equivalent circuit of the first embodiment.

FIG. 3 is a waveform diagram provided for explaining the operation of the first embodiment,
9A is a waveform diagram of a video signal with respect to the image pattern of FIG. 9B is a waveform diagram showing a state in which the convergence correction waveform is clamped at a high voltage

FIG. 4 is a waveform diagram showing a state in which a horizontal output pulse and a convergence correction waveform are clamped to a high voltage in the waveform diagram provided for explaining the operation of the first embodiment.

FIG. 5 is a partial cross-sectional view of a color CRT showing a second embodiment of the present invention, where A is a Y cross section near the convergence plate, B is the opposite side of A, and C is near the convergence plate. Figure showing X section of

FIG. 6 is a circuit diagram showing an equivalent circuit of the second embodiment.

7A and 7B are waveform diagrams for explaining the operation of the second embodiment, where A is a waveform diagram of a video signal with respect to the video pattern of FIG. 9 and B is a convergence correction waveform, which allows constant correction while following the high voltage HV. Waveform diagram showing the state

FIG. 8 is a waveform diagram showing the operation of the embodiment, showing a state where the convergence correction waveform and its induced waveform are clamped to a high voltage HV.

FIG. 9 is a diagram showing a screen used for explaining occurrence of a convergence error.

10 is a waveform diagram for explaining the occurrence of a convergence error, A is a waveform diagram of a video signal corresponding to the image pattern of FIG. 5, B is a waveform diagram for explaining the convergence error, and C is a waveform of the convergence voltage. Figure

FIG. 11 is a curve diagram showing misconvergence.

FIG. 12 is a partial cross-sectional view of a conventional color CRT.

FIG. 13 is an equivalent circuit of a conventional technique.

FIG. 14 is an equivalent circuit showing an improved version of the prior art.

FIG. 15 is a waveform diagram used to explain the occurrence of a convergence error according to an improved version of the conventional technique.

[Explanation of symbols]

1, 2 pairs of high-voltage side electrode plates 3, 4 pair of low-voltage side electrode plates 7A, 7D inner conductive layers 7B, 7C outer conductive layers C1, C21 first capacitor C2, C22 second capacitor D1, D21 first Diode D2, D22 Second diode R1, R21 First high resistance R2, R22 Second high resistance HV High-voltage DC voltage e _c2 , e _{c 11} , e _{c 12} Convergence correction voltage e _c4 Horizontal output pulse e _{C 13} Correction signal induced on the high voltage side electrode plate

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ryoshin Iguchi 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Within Sony Corporation (56) References JP-A-49-98573 (JP, A) JP Hei 6-165195 (JP, A) Japanese Patent Sho 55-20633 (JP, B1) Actual Japanese Sho 52-48666 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 9 / 28 H01J 29/76 H04N 3/185

Claims (3)

(57) [Claims] 1. A pair of high voltage side electrode plates, a pair of high voltage side electrode plates facing each other, and a pair of low voltage side electrode plates arranged on both outer sides of the pair of high voltage side electrode plates so as to face the pair of high voltage side electrode plates. Is arranged horizontally inside the tube body of the color cathode-ray tube so that the central electron beam passes therethrough and the electron beams on both sides pass between the pair of high voltage side electrode plates and the pair of low voltage side electrode plates. The anode side end of the first diode of the parallel circuit of the high resistor and the first diode is commonly connected to the pair of low voltage side electrode plates, and the cathode side end is commonly connected to the pair of high voltage side electrode plates. The second side in which the cathode side is connected to the pair of low-voltage side electrode plates
The anode side of the diode and the one end of the second high resistor are commonly connected, and the other end of the second high resistor is connected to the pair of high voltage side electrode plates, and the high voltage DC voltage is applied to the pair of high voltage A modulated voltage (convergence correction voltage) obtained by amplitude-modulating a horizontal period parabolic wave with a vertical period parabolic wave is supplied to the pair of low voltage side electrode plates through a first capacitor while being applied to the side electrode plate. And the pulse signal of the horizontal cycle is
Is supplied to the anode side of the second diode through the capacitor, and the time constant of the first capacitor and the first high resistor is the time constant of the second capacitor and the second high resistor. A dynamic convergence device characterized by being selected to be larger. 2. A pair of high-voltage side electrode plates facing each other,
A central electron beam passes between a pair of low-voltage side electrode plates arranged on both outer sides so as to face the pair of high-voltage side electrode plates,
A first high resistor and a first diode are arranged horizontally inside the tube body of the color cathode ray tube so that electron beams on both sides pass between the pair of high voltage side electrode plates and the pair of low voltage side electrode plates. Of the parallel circuit, the anode side end of the first diode of the parallel circuit is commonly connected to the pair of high voltage side electrode plates, the cathode side is connected to the high voltage power source, and the anode side is the first capacitor. Is connected to the cathode side of the second diode, and the anode side of the second diode is commonly connected to the high-voltage side electrode plate, and is further connected between the anode side of the second diode and the high-voltage power supply. A second high resistor is connected, and a modulated voltage (convergence correction voltage) obtained by amplitude-modulating a horizontal period parabolic wave with a vertical period parabolic wave is passed through a second capacitor to the second die. Dynamic convergence device and supplying to the anode side of the chromatography mode. 3. The time constant of the first capacitor and the first high resistor has a time constant of the second capacitor and the second capacitor.
3. The dynamic convergence device according to claim 2, wherein the time constant is selected to be larger than the time constant of the high resistance device.