JP3475605B2 - Convergence correction 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 convergence correction device suitable for use in, for example, a wide screen or a color cathode ray tube used at a plurality of deflection frequencies.

[0002]

2. Description of the Related Art In the field of image display tubes such as color cathode ray tubes, a large amount of anode current flows in a bright screen (high brightness) and decreases in a dark screen (low brightness). That is, it is known that the high voltage is lower in the bright screen than in the dark screen.

On the other hand, in a color cathode ray tube, for example, three R, G, and B electron beams forming a color image are gathered at one point regardless of which position on the screen of the color cathode ray tube is deflected. A convergence corrector is used.

In such a convergence correction device, for example, a Trinitron type (trade name) color cathode ray tube has a convergence (CV) plate as shown in FIG. 3 and has a bleeder resistance R _IBR inside the neck of the cathode ray tube. And a high voltage is divided by a resistance division consisting of a convergence adjusting volume (VR) to obtain a convergence voltage.

Therefore, in a color cathode ray tube in which, for example, the static convergence in the horizontal direction is adjusted by the action of the electric field due to the potential difference between the convergence voltage thus obtained and the high voltage, the fluctuation of the high voltage and the followability of the convergence (tracking). ) Becomes important.

Here, in the conventional device, the fluctuation of the screen brightness is the change of the charge velocity of the electron beam. Therefore, even if the high voltage is lowered in the conventional device, the voltage generated in the convergence plate that adjusts the static convergence is also lowered, so that the tracking is matched. Further, in the conventional device, the deflection frequency is often single, and the change in luminance is not large.

Further, for example, in the cathode ray tube of the Trinitron system (trade name), not only a part of the high voltage current is shunted as a focus voltage, but also a shunt current is applied to give a voltage to the convergence plate, so that a high voltage regulation ( Stability) was improved and fluctuations were even smaller.

Under such circumstances, in the conventional convergence correction device, the misconvergence due to the high pressure fluctuation does not pose a problem so much. Therefore, the information of the high voltage fluctuation (the signal which detects the high voltage fluctuation) is used as the convergence correction information. Was never used.

Further, FIG. 4 shows a mechanism of dynamic convergence correction in such a conventional display device, and FIG. 5 shows a circuit example of a convergence correction circuit. That is, FIG. 4 shows an example of the configuration of the convergence yoke L _CY using the coil formed by the E-shaped core.

In FIG. 5, block 1 is a voltage source for supplying energy to the resonance circuit, block 2 is a resonance circuit for generating a convergence correction waveform, block 3 is a current source for superimposing a DC component on the correction waveform, and block 4 is a block 4. Block 5 is a feedback circuit for stabilizing the circuit,
The coil L _CY in the resonance circuit of the block 2 is a convergence yoke that generates a correction magnetic flux by _passing a current.

In the convergence correction circuit thus configured, the resonance circuit of the block 2 causes resonance in the trace section by the resonance capacitors C _C1 + C _C2 and the convergence yoke L _CY , and the resonance capacitors C _C1 + C _C2.
And the coil L1 causes resonance in the retrace section.

Therefore, these convergence yokes L
For example, as shown in D of FIG. 6, by switching and switching the two inductances of _CY and the coil L1 at the PWM timing shown in FIG. 6B, which is synchronized with the deflection frequency input to the point a. Generates a horizontal period parabolic wave synchronized with the deflection frequency.

That is, first, resonance in the trace section is performed by the resonance capacitors C _C1 + C _C2 and the convergence yoke L _CY . Before the polarity is inverted and the next half-wave cycle starts, the resonance capacitor C _{c1 is} switched by the switch of the transistor Q1.
Resonance of the retrace section by + C _C2 and the coil L1 is started.

As a result, the resonance in the retrace section tries to enter the next half-wave cycle after the first half-wave cycle ends and the polarity is reversed, but the current does not flow after the polarity reversal due to the diode D4. The resonance of will start. Therefore, a parabolic wave having a horizontal period synchronized with the deflection frequency as shown by D in FIG. 6 is generated.

Further, it is the voltage source of the block 1 that gives energy to this resonance circuit, and by performing power source modulation by the waveform input to the points b and d in the figure, the parabolic wave of the horizontal period described above can be arbitrarily set. The waveform can be amplitude-modulated. As a result, the correction magnetic flux in the vertical direction at the horizontal left and right ends of the screen changes, and the vertical correction of the horizontal left and right ends of the screen becomes possible.

Further, the direct current component of the resonance current is superposed on the current of the resonance waveform by the current source of the block 3, and the direct current component of the resonance current is modulated by modulating the direct current component in the vertical cycle by the waveform inputted to the point c in the figure. The magnetic flux changes and the correction magnetic flux changes in the vertical direction with respect to the horizontal center of the screen, and the upper and lower ends of the horizontal center of the screen can be corrected.

That is, for example, in a color cathode ray tube, after the static convergence adjustment, for example, horizontal dynamic misconvergence as shown in FIG. 7 occurs. In order to correct this horizontal dynamic misconvergence, the above-mentioned convergence yoke L _CY is attached to the neck of the cathode ray tube, and a parabola waveform with a horizontal period as shown in FIG. 6 is passed through this convergence yoke L _CY and its current I _CY is corrected. Generating a magnetic field.

Therefore, in this device, when a parabola wave having a horizontal period is flown through the convergence yoke, a vertical magnetic flux connecting both ends of the magnetic pole acts on the electron beam as shown by a dotted line in FIG. 4, and a direction perpendicular to the magnetic flux, that is, FIG. The beam moves horizontally in the direction of the arrow at. This causes the electron beams R and B to overlap the electron beam G on the tube surface.

Further, as shown in FIG. 7, in the dynamic misconvergence pattern in which the amount of misconvergence is small in the central part and the amount of misconvergence increases as it goes to the periphery, a correcting action is made in the central part by passing a parabola-shaped current. It is possible to increase the correction effect in the peripheral portion with less.

Further, the change in the correction amount in the vertical direction is realized by adding modulation in a vertical cycle as shown in A and B of FIG. 8 to the resonance waveform by amplitude modulation or superposition of a DC component. .

In block 4 of FIG. 5, current is detected by a resistor for peak detection, and in block 5, the voltage extracted by capacitance division is peak-detected and fed back to stabilize the circuit. It is a thing.

[0022]

In recent years, in the field of image display tubes such as color cathode ray tubes, the size of the screen is increased and
It is required that the aspect ratio of the screen be wide in the horizontal direction such as 9:16, and that the brightness of the displayed image is also high. Further, due to the widespread use of so-called high-definition television and computers, the frequency deflected as a display device has been increased and a plurality of frequencies have been increased.

Therefore, as the color cathode ray tube becomes larger and the brightness becomes higher, a higher voltage is used as the voltage supplied to the anode of the color cathode ray tube, and the R, G, and B electron beams are used. We are also trying to increase the brightness of the screen by increasing the drive amount of each cathode that generates.

For this reason, it becomes difficult to track the high voltage and the voltage for adjusting the convergence due to the increase of the high voltage fluctuation due to the expansion of the change of the screen brightness and the diversification of the high voltage due to the plural deflection frequencies. It was

Further, as shown in FIG. 3, since the resistor portion for generating a high voltage partial pressure used for convergence has a capacitive component, a delay having a time constant is generated, and a screen image as shown in FIG. In the screen where the area has high brightness, the voltage of the convergence plate does not follow the high voltage fluctuation due to the brightness change, resulting in misconvergence.

Further, since the speed of the charge increases as the brightness becomes higher even if the fluctuation of the high voltage is small, the beam cross point shifts due to the fluctuation of the charge speed due to the tracking with the potential of the prefocus system, which causes the misconvergence. Becomes

Therefore, in obtaining a high-definition image on the large-sized screen, the high-luminance screen, or the color cathode-ray tube in which the deflection frequency is widely used, it is possible to correct the misconvergence due to the fluctuation of the high voltage. Is desired.

This application has been made in view of such a point, and a problem to be solved is a large screen, a high-brightness screen, and a color cathode ray tube in which a deflection frequency is widely used. When obtaining a fine image, misconvergence occurs due to the fluctuation of the high voltage as described above.

Therefore, it is an object of the present invention to provide a convergence correction device which improves the high-speed followability of convergence due to high-voltage fluctuations as described above and is capable of correcting misconvergence with respect to changes in screen brightness. Is.

[0030]

Therefore, in the present invention, a high voltage fluctuation is detected and the detected waveform is manipulated to
The signal related to this high voltage fluctuation amount is fed back to the convergence correction circuit,
According to this, it is possible to improve the high-speed followability of the convergence with respect to the change of the high voltage, and to improve the misconvergence with respect to the change of the screen brightness.

[0031]

DETAILED DESCRIPTION OF THE INVENTION Namely, the present invention, the high voltage circuit
Of the color cathode ray tube in which the high voltage of
Yoke attached to the rack and having a coil for applying a magnetic field to the electron beam of the color cathode ray tube
And a horizontal parabolic wave signal synchronized with the horizontal frequency
Generated by modulating with a vertical parabolic wave signal synchronized with the wave number
A convergence correction circuit for supplying a correction current to the coil of the convergence yokes, a color cathode ray tube anode -
It is placed in the path of the ed current and converts the anodic current into voltage.
Integrates the sense resistor and the voltage signal detected by the sense resistor
It has an integrating circuit that
Of the high voltage for the anodic current due to the time constant
The voltage signal is adjusted by the integrator circuit so that the voltage signal is adjusted to the delay.
Corrected, and the corrected voltage signal into a vertical parabolic wave signal
And a waveform operation circuit for adding those made Bei Ete.

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an example of an embodiment of a convergence correction device according to the present invention. Note that, in FIG. 1, the convergence correction device of the present embodiment is
It is applied to the convergence correction circuit shown in FIG. This convergence correction circuit is shown as block C in FIG.

Therefore, in this embodiment, as shown in FIG.
1 for the coil for applying a magnetic field to the electron beam and the conventional convergence correction circuit (block C) for generating a correction current synchronized with the deflected frequency in the coil to apply a magnetic field to the electron beam. A circuit for detecting a high-voltage fluctuation shown in block A and a circuit for manipulating the detected waveform shown in block B are provided, and a signal related to this high-voltage fluctuation amount is fed back to the convergence correction circuit (block C). To be done.

Therefore, FIG. 2 shows an embodiment of the waveform manipulating circuit of the block B of FIG. That is, the voltage V _ABL generated in the resistor R _ABL in the block A of FIG. 1 is related to the high voltage because it changes depending on the current flowing through the flyback transformer FBT that generates the high voltage. Therefore, this voltage V
_ABL is applied to detect high pressure fluctuations. The circuit block A has been conventionally used for other purposes.

The further detected signal (voltage V _ABL ) is
It is fetched by the buffer in the waveform manipulation circuit of block B in FIG. In FIG. 2, the resistor R2
The Zener diode D5 after the buffer composed of 0, R21, R22 and the transistors Q2, Q3 is for a signal limiter.

Here, the voltage V _ABL generally has a time constant of integral action with the high voltage. Therefore, waveform operation is performed to compensate for this time constant and for tracking correction with the convergence voltage. That is, in FIG.
23, R24, R25 and capacitors C7, C8 form a waveform operating circuit.

Therefore, the waveform manipulation for correcting the low frequency component of the high voltage fluctuation, that is, the average fluctuation is performed by the integration by the resistor R23 and the capacitor C7. Further, the capacitor C8 performs a waveform operation for correcting a high frequency component, that is, a high speed followability. Note that resistors R24 and R25
Each adjusts its signal level.

The correction signal thus generated in waveform is fed back to the conventional convergence correction circuit of block C in FIG. That is, the correction waveform fed back is added to, for example, the point e or the point f in the convergence correction circuit of FIG. 5 described above.

Therefore, the direct current component of the vertical period of the convergence correction current I _CY is corrected by the correction signal added to the point e, and the tracking with the high voltage change of the convergence and the high speed followability are improved. This compensates for static convergence fluctuations due to high pressure.

In addition, the amplitude of the horizontal component of the convergence correction current I _CY is corrected by the correction signal added to the point f, and tracking with the potential of the prefocus system causes the beam cross point to shift due to high-speed fluctuations in charge. Misconvergence is improved. This compensates for dynamic convergence fluctuations due to high pressure.

Therefore, in this apparatus, it is possible to detect a high voltage fluctuation, manipulate the detected waveform, and feed back a signal related to this high voltage fluctuation amount to the convergence correction circuit. That is, as described above, the contents of the present invention are implemented by using the waveform operation circuit block B which is an additional circuit between the conventional circuit blocks A and C.

Thus, in the past, when obtaining a high-definition image on a large-sized screen, a high-brightness screen, or a color cathode-ray tube with a wide range of deflection frequencies, a misconvergence caused by a change in high voltage was generated. According to the present invention, it is possible to improve the high-speed followability of convergence with respect to fluctuations in high voltage, and improve misconvergence with respect to changes in screen brightness.

Further, in the present invention, the change in the time constant due to the difference in the deflection frequency is reflected in the detection of the high voltage.
It can also handle multiple deflection frequencies for so-called high-definition and computers. Furthermore, it can be used by adding it to the conventional circuit, making it possible to share the basic circuit,
It is also advantageous in terms of cost.

Thus, according to the above-mentioned convergence correction device, the high voltage from the high voltage circuit is supplied to the node.
Attached to the neck of the color cathode ray tube,
Has a coil for applying a magnetic field to the electron beam of a polar tube
Convergence yoke and water synchronized with horizontal frequency
Vertical parabola in which a flat parabolic wave signal is synchronized with the vertical frequency
Convergence of the correction current generated by modulating the wave signal
A convergence correction circuit for supplying to the yoke of the coil, a color cathode ray tube anode - placed in the path of de current, A
Roh - a detection resistor to convert the de current to voltage, the detection resistor
Has an integrating circuit that integrates the voltage signal detected by
Ano due to the time constant due to the resistance and capacitance components of the circuit
-Adjust the voltage signal to the delay of the high voltage with respect to the dead current.
The voltage signal is corrected by the integrating circuit, and the corrected voltage is corrected.
By signal obtaining <br/> Bei a waveform operation circuit for adding the vertical parabola wave signal, it is possible to improve the convergence fast tracking of relative variations in pressure, improving the misconvergence with respect to the brightness of the screen changes It is possible.

[0045]

According to the present invention, high pressure fluctuations are detected,
By manipulating this detected waveform and feeding back a signal related to this high-voltage fluctuation amount to the convergence correction circuit, the high-speed tracking of convergence for high-voltage fluctuations is improved, and misconvergence with respect to changes in screen brightness is improved. Can be improved.

Further, since the change in the specific number due to the difference in the deflection frequency is also reflected in the detection of the high voltage, it is possible to deal with a plurality of deflection frequencies of so-called high-definition televisions, computers and the like. Further, it can be used in addition to the conventional circuit, the basic circuit can be made common, and the advantageous effect in terms of cost can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an example of a convergence correction circuit according to the present invention.

FIG. 2 is a circuit diagram showing a configuration of an example of a waveform manipulation circuit added to the convergence correction circuit in the present invention.

FIG. 3 is a diagram showing the function of a convergence (CV) plate.

FIG. 4 is a diagram showing a mechanism of a convergence yoke L _CY and dynamic convergence correction.

FIG. 5 is a circuit diagram of an example of a conventional convergence correction circuit.

FIG. 6 is a diagram showing waveform timings in the dynamic convergence correction circuit.

FIG. 7 is a diagram showing a symmetrical shift of R and B with respect to G on the tube surface.

FIG. 8 is a waveform diagram showing how the convergence correction current I _CY changes due to a voltage change of a parabola wave having a vertical cycle.

FIG. 9 is a diagram showing a state of each part when a high pressure fluctuates.

[Explanation of symbols]

R _IBR1, R _IBR2 Cathode ray tube neck internal bleeder resistance I _CY Convergence yoke current L _CY Convergence yoke L1, 2 Coils C _C1 , C _C2 Resonance capacitors _{C1 to} C8 Capacitors R1 to R25 Resistors D1 to D4 Diodes D5 Zener diodes Q1 ~Q3 transistor R _ABL detection resistor V _ABL detection voltage FBT flyback transformer VCC (+ B) positive power supply voltage VEE negative supply voltage HV high

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Claims (2)

(57) [Claims] 1. A high voltage from a high voltage circuit is supplied to an anode.
It is attached to the neck of the color cathode ray tube to be supplied and
Coil for applying a magnetic field to the electron beam of a Rah cathode ray tube
And convergence yoke having a vertical frequency horizontal parabolic wave signal synchronized with the horizontal frequency
Correction generated by modulation with vertical parabolic wave signal synchronized with
A convergence correction circuit for supplying current to the coils of the convergence yokes, the color cathode ray tube anode - is placed in the path of de current, upper
A detection resistor that converts the anodic current into a voltage, and an integration that integrates the voltage signal detected by the detection resistor.
It has a circuit and depends on the resistance component and the capacitance component of the above high voltage circuit.
Of the high voltage for the above anodic current due to the time constant
The above integration circuit is used to adjust the voltage signal to the delay.
The voltage signal is corrected, and the corrected voltage signal is added to the vertical
Convergence correction apparatus characterized by obtaining Bei a waveform operation circuit for adding the parabolic wave signal. 2. The high voltage from the high voltage circuit is supplied to the node.
It is attached to the neck of the color cathode ray tube to be supplied and
Coil for applying a magnetic field to the electron beam of a Rah cathode ray tube
Convergence yoke with horizontal parabolic wave signal synchronized with horizontal frequency and vertical frequency
Correction generated by modulation with vertical parabolic wave signal synchronized with
Supply current to the coil of the convergence yoke
The convergence correction circuit compares the vertical parabola signal with the reference voltage.
A direct current component having a path and corresponding to the comparison result by the comparison circuit.
Is a voltage that is superimposed on the correction current supplied to the coil.
The source circuit and the anode current path of the color cathode ray tube
A detection resistor that converts the anodic current into a voltage, and an integration that integrates the voltage signal detected by the detection resistor.
It has a circuit and depends on the resistance component and the capacitance component of the above high voltage circuit.
Of the high voltage for the above anodic current due to the time constant
The above integration circuit is used to adjust the voltage signal to the delay.
The voltage signal is corrected, and the corrected voltage signal is compared with the above.
Add to the vertical parabolic wave signal input to the circuit
Convergence correction device characterized by comprising a wave operation circuit.