JPH0150158B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a convergence correction circuit in a color receiver using a cathode ray tube having an in-line three-electron gun.

Conventionally, in an in-line type three-electron gun cathode ray tube provided with a self-convergence yoke, the deflection yoke has been operated to correct the concentration deviation of the electron beam, that is, the misconvergence.

1 and 2 are raster pattern diagrams of misconvergence, and numerals 1 and 2 in the figures indicate rasters misconverged by the respective side beams on both sides, respectively. Misconvergence as shown in Figure 1 can be corrected by adjusting the deflection yoke in the horizontal direction, and misconvergence as shown in Figure 2 can be corrected by adjusting the deflection yoke in the vertical direction. It was corrected by.

However, if the electron gun is installed in a twisted manner when it is sealed in the neck of the tube, a parabolic misconvergence like the raster pattern shown in FIG. 3 or 4 will occur depending on the direction of the twist. Moreover, this parabola does not necessarily occur symmetrically. Since such parabolic misconvergence cannot be corrected even by adjusting the deflection yoke, there is a problem in that it remains as it is and significantly deteriorates the quality of the image.

The present invention was made to solve these conventional problems, and its purpose is to:
An object of the present invention is to provide a convergence correction circuit that can sufficiently correct parabolic misconvergence. Hereinafter, the present invention will be explained in detail with reference to Examples.

Before entering into the description of the present invention, a convergence yoke that performs convergence correction will be described.

FIG. 5 is a configuration diagram of a convergence yoke conventionally used for dynamic convergence correction of a separate in-line electron gun tube. In the figure, 3 and 4 are E-shaped cores, 5a, 5b and 6a, 6b are horizontal concentrated coils wound on both sides of cores 3 and 4, respectively, and 7 and 8 are at the center of cores 3 and 4. Terminals a and b are for supplying current to the horizontal concentrated coils 5a, 5b, 6a, and 6b, and terminals c and d are for supplying current to the vertical concentrated coils 7 and 8. The terminals B ₁ and B ₂ are the left and right side beams of the electron gun. Horizontal concentrated coil 5
The side beams B ₁ and
B ₂ can be concentrated in the horizontal direction, and the side beams B ₁ and B ₂ can be
can be concentrated vertically. Therefore, by supplying currents with predetermined waveforms to terminals a, b, c, and d, the side beams B ₁ and B ₂ can be concentrated over the entire screen, as shown in FIGS. 3 and 4. This makes it possible to correct parabolic misconvergence.

FIG. 6 is a block circuit diagram of an embodiment of the convergence correction circuit according to the present invention, and FIG. 7 is a waveform diagram of each signal. A vertical deflection signal as shown in FIG. 7a is supplied from a vertical output circuit (not shown) to the input terminal Vin, and this signal is input to the vertical sawtooth wave generation circuit 10. This vertical sawtooth wave generating circuit 10 generates a vertically periodic sawtooth wave signal as shown in FIG. In the integrating circuit 11, the sawtooth wave signal is converted into an integrated parabolic wave signal as shown in FIG. converted into a wave signal. These parabolic wave and square wave signals are input to vertical amplitude adjustment circuits 13 and 14, respectively. In the vertical amplitude adjustment circuits 13 and 14, the amplitude and polarity are arbitrarily and independently adjusted by external operations in the first half and the second half of one period of the parabolic wave, as shown in FIG. 7e.

On the other hand, a horizontal deflection signal is supplied to the input terminal Hin from a horizontal output circuit (not shown) and inputted to the horizontal sawtooth wave generation circuit 15, which generates a horizontal periodic sawtooth wave signal synchronized with the horizontal deflection. This signal is converted into a parabolic wave signal by an integrating circuit 16, and converted into a square wave signal by a Schmitt trigger circuit 17. The parabolic wave signal and the square wave signal are input to horizontal amplitude adjustment circuits 18 and 19, respectively, where the amplitude and polarity of the first and second half of one period of the parabolic wave are arbitrarily and independently adjusted by external operation. be done. The above operation is exactly the same as in the case of vertical signals, only the period is different.

Then, the parabolic wave signal of the vertical flag output from the vertical amplitude adjustment circuit 13 and the horizontal amplitude adjustment circuit 1
The horizontally periodic parabolic wave signals outputted from 8 are both input to a balanced modulator 20 and balanced modulated.
Further, this balanced modulated signal and the vertically periodic parabolic wave signal are added in an adder circuit 21, and this added signal is amplified in an amplifier 22 and then horizontally concentrated coil 23 of the convergence yoke (5 in FIG. 5).
a, 5b, 6a, 6b).

On the other hand, the vertical period parabolic wave signal output from the vertical amplitude adjustment circuit 14 and the horizontal amplitude adjustment circuit 19
Both of the horizontally periodic parabolic wave signals outputted from are input to the balanced modulator 24, where they are balanced-modulated. Furthermore, this balanced modulated signal is amplified by an amplifier 25 and then supplied to a vertical concentration coil 26 (corresponding to 7 and 8 in FIG. 5) of the convergence yoke.

FIG. 8a is a waveform diagram of the signal supplied to the horizontal concentrated coil 23, and FIG. 8b is an enlarged waveform diagram of one horizontal period. Since the amplitude and polarity of the first and second half of the vertical period parabolic wave can be varied by adjusting the two positions of the vertical amplitude adjustment circuit 13, the parabolic misconvergence above and below the vertical line at the center of the screen can be adjusted independently. . Furthermore, since the amplitude and polarity of the first and second half of the parabolic wave of the horizontal period can be varied by adjusting two parts of the horizontal amplitude adjustment circuit 18, the parabolic misconvergence at the top and bottom of the vertical lines on the left and right sides of the screen can be adjusted independently for the left and right sides. be able to.

FIG. 9a is a waveform diagram of the signal supplied to the vertical concentrated coil 26, and FIG. 9b is an enlarged waveform diagram of one horizontal period. Since the amplitude and polarity of the first half and the second half of the parabolic wave of the horizontal period can be varied by adjusting the two positions of the horizontal amplitude adjustment circuit 19, the parabolic misconvergence on the left and right sides of the horizontal line at the center of the screen can be adjusted independently. Furthermore, since the amplitude and polarity of the first and second half of the parabolic wave of the vertical period can be varied by adjusting two parts of the vertical amplitude adjustment circuit 14, the parabolic misconvergence of the horizontal lines at the top and bottom of the screen can be adjusted independently. .

By arbitrarily making adjustments at eight locations in this way, it becomes possible to completely correct parabolic misconvergence as shown in FIGS. 3 and 4.

Next, the vertical and horizontal amplitude adjustment circuits shown in FIG. 6 will be explained in more detail.

FIG. 10 is a circuit diagram of the principle of such an amplitude adjustment circuit. In the figure, an input signal ei is input to a non-inverting input terminal 30a of an operational amplifier 30, and a variable resistor _R1 and a resistor _R3 are connected to each other depending on the operating state of an analog switch _S1 .
Alternatively, the voltage is divided by the variable resistor R ₂ and the resistor R ₃ and inputted, and the resistor R ₄ is input to the inverting input terminal 30b.
Negative feedback is provided by _R5 . Since the amplitude of the operational amplifier 1 is set to be very large, when the analog switch _S1 is turned on to the variable resistor _R1 side, the output signal eo is expressed by the following equation.

eo = R ₃ / R ₄ (R ₄ + R ₅ / R ₁ + R ₃ − R ₅ / R ₃ ) ei In this formula, the amplitude and polarity of the output signal eo can be changed arbitrarily by changing the value of variable resistor R ₁ . Can be adjusted continuously. When the analog switch _S1 is turned on to the variable resistor _R2 side, the amplitude and polarity of the output signal eo can be arbitrarily and continuously adjusted by similarly changing the value of the variable resistor _R2 . Therefore, if the analog switch _S1 is switched using the square wave signal outputted from the Schmitt trigger circuit shown in FIG. The amplitude and polarity of the first half and the second half of one cycle can be varied independently.

FIG. 11 is a circuit diagram of a specific embodiment of such an amplitude adjustment circuit. For example, a parabolic wave signal with a vertical period is input to the input terminal 31, and the terminals 32,
When a square wave signal with equal vertical period and different polarity and different duty is input to the output terminal 33, the output terminal 34
A parabolic wave signal in which the amplitude and polarity of the first half and the second half of one vertical period of the parabolic wave are adjusted independently is output. Note that FET ₁ and FET ₂ are FET transistors, Q ₁ to Q ₆ are transistors, D ₁ and D ₂ are diodes, VR ₁ and VR ₂ are variable resistors, and R ₆ to _{R 21} are resistors.

As described above, the convergence correction circuit according to the present invention easily corrects parabolic misconvergence that cannot be corrected by the swinging of the deflection yoke of an in-line 3 electron gun tube using a convergence yoke. It is possible,
Furthermore, since adjustments can be made independently at each of the eight locations, it is possible to almost completely correct parabolic misconvergence on the entire screen, resulting in the advantage of obtaining high-quality images.

[Brief explanation of drawings]

Figures 1 to 4 are raster pattern diagrams of misconvergence, Figure 5 is a configuration diagram of a convergence yoke, Figure 6 is a circuit diagram of an embodiment of the convergence correction circuit according to the present invention, and Figure 7 is a diagram of each signal. Figure 8a is a waveform diagram of the signal supplied to the horizontal concentrated coil, Figure 8b is an enlarged waveform diagram, and Figure 9a is a waveform diagram of the signal supplied to the horizontal concentrated coil.
9 is a waveform diagram of the signal supplied to the vertical concentrated coil, FIG. 9b is an enlarged waveform diagram, FIG. 10 is a principle circuit diagram of the amplitude adjustment circuit, and FIG. 11 is a specific circuit diagram of the amplitude adjustment circuit. 10... Vertical sawtooth wave generation circuit, 11, 16...
...Integrator circuit, 12, 17... Schmitt trigger circuit, 13, 14... Vertical amplitude adjustment circuit, 15...
Horizontal sawtooth wave generation circuit, 18, 19... Horizontal amplitude adjustment circuit, 20, 24... Balanced modulator, 21...
Adding circuit, 22, 25...amplifier, 23...horizontal concentrated coil, 26...vertical concentrated coil.

Claims (1)

[Claims] 1 In the convergence correction circuit of a color receiver using a cathode ray tube with three in-line electron guns, there is a circuit that generates a sawtooth wave with a vertical period synchronized with vertical deflection, and the output of this circuit is converted into a vertical parabolic wave. an integrating circuit and a Schmitt trigger circuit for converting into a vertical square wave with equal duty;
A first device capable of adjusting the amplitude and polarity of the first half and the second half of the vertical parabolic wave using the vertical square wave as a switching signal.
and a second vertical amplitude adjustment circuit, a circuit that generates a sawtooth wave with a horizontal period synchronized with horizontal deflection, an integrating circuit that converts the output of this circuit into a horizontal parabolic wave, and a horizontal square wave with equal duty. a Schmitt trigger circuit, first and second horizontal amplitude adjustment circuits capable of adjusting the amplitude and polarity of the first and second half of the horizontal parabolic wave using the horizontal square wave as a switching signal; and an output of the first horizontal amplitude adjustment circuit. a first balanced modulator that performs balanced modulation using the output of the first vertical amplitude adjustment circuit; an addition circuit that adds the output of the first balanced modulator and the output of the first vertical amplitude adjustment circuit; a second balanced modulator that balance-modulates the output of the second horizontal amplitude adjustment circuit with the output of the second vertical amplitude adjustment circuit, and amplifies the output of the addition circuit and supplies it to a horizontal concentrated convergence coil. A convergence correction circuit for a color receiver using a cathode ray tube having an in-line three-electron gun, wherein the output of the second balanced modulator is supplied to a vertical concentrated convergence coil.