JPS6016070A - Picture distortion correcting device - Google Patents

Abstract

PURPOSE:To correct the picture distortion due to high voltage fluctuation by providing the 1st S-shape correcting capacitor connected in series with a deflection coil and the 2nd S-shape correcting capacitor having a capacitance value smaller than the capacitance value of the 1st capacitor. CONSTITUTION:The 1st S-shape correcting capcitor 15 and the horizontal deflection coil 17 are connected in series and also connected in series with the 1st damper diode 13. Further, the connecting midpoint between the capacitor 15 and the coil 17 is grounded via the 2nd S-shape correcting capacitor 16. Through the constitution above, the horizontal scanning of the electron beam of a cathode- ray tube (not shown) is conducted by flowing a deflection current to the coil 17 while using the primary winding 18 of a flyback transformer 30 as a choke coil through the switching operation of a transistor 11 in response to the horizontal drive pulse. In this case, very excellent correction is conducted by using a capacitance of the capacitor 16 as 1/3-1/10 of the capacitance of the capacitor 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image distortion correction device applied to a television receiver using a cathode ray tube, and in particular, the present invention relates to an image distortion correction device applied to a television receiver using a cathode ray tube. This is for correcting image distortion caused by fluctuations.

Now, we will configure the circuit by integrating the high voltage generation system and the horizontal deflection system so that the primary winding of the flyback transformer in the high voltage generation system for driving the cathode ray tube is used as a choke coil for the horizontal deflection system. A simplified deflection circuit is used.

In this type of television receiver, when a video signal of an image with a large contrast ratio is supplied, the high-voltage load current increases due to a sudden change in the brightness level of the video signal, causing the high-voltage generation system to receive high voltage. It is known that the horizontal deflection current is modulated by this high voltage fluctuation, resulting in image distortion. Image distortion caused by the above-mentioned high voltage fluctuations appears asymmetrically on the left and right sides of the screen. For example, for a video signal of a window-like image of white on a black background, as shown by the solid line in Fig. 1, the image distortion shown by the broken line in Fig. 1 Screen 1 as shown
It appears approximately trapezoidal at the top.

In order to correct the above-mentioned left-right asymmetric image distortion, conventionally, the retrace
By integrating L/s, only the envelope is taken out, and this envelope signal is applied to the horizontal oscillation system AFC.
Methods such as superimposing it on the control voltage and improving the regulation of the high voltage generation system were adopted.

However, conventional image distortion correction apparatuses employing the various methods described above have the drawbacks of complicated configurations, resulting in increased size and cost of the apparatus as a whole.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention provides an image distortion correction device that can effectively correct image distortion with an extremely simple configuration, and provides a compact and high-performance television receiver. The purpose is to make it possible.

[Summary of the invention]

In order to achieve the above-mentioned object, the image distortion correction device according to the present invention includes a switching element connected to a power input terminal via the primary winding of a flyback transformer, and a resonator connected in parallel to the switching element. capacitor and each other
first and second damper diodes connected in series and connected in parallel to the switching element; and a first damper diode connected in series to each other, connected in series to the first damper diode and in parallel to the second damper diode. a figure-eight correction capacitor and a deflection coil; a second figure-eight correction capacitor connected in parallel to the first damper diode and in series with the deflection coil and having a smaller capacitance value than the first eight-order correction capacitor; It is equipped with a character correction capacitor.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image distortion correction device according to the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a circuit diagram showing a circuit configuration of a specific embodiment of the present invention.

In FIG. 2, 11 is a transistor used as a switching element, and this 1-transistor 11 performs a switching operation in response to a horizontal drive pulse supplied to its base from a horizontal oscillation circuit (not shown). Transistor 11 as the switching element
The collector is connected to the power input terminal 19 via the primary winding 18 of the flyback transformer 30 for high voltage generation, and the emitter is grounded.

Note that a power source 20 is connected to the power input terminal 19.

Further, 12 is a resonant capacitor for flyback pulse, and this resonant capacitor 12 is connected to the transistor 11.
is connected in parallel to a switching element using That is, the collector of the transistor 11 is grounded via the resonant capacitor 12.

Further, 13 and 14 are first and second damper diodes, and this first damper diode 13
has an anode grounded, a cathode connected to the anode of the second damper diode 14, and a cathode of the second damper diode 14 connected to the collector of the transistor 11. That is, the damper diodes 13 and 14 are connected in series with each other and in parallel with the transistor 11, that is, the switching element.

15 and 16 are first and second figure-of-eight correction capacitors, and 17 is a horizontal deflection coil. The first figure-8 correction capacitor 15 has one end connected to the connection midpoint of the valley damper diode 13°14,
Further, the other end is connected to the cathode of the second damper diode 14 via the horizontal deflection coil 17.

That is, the first figure-8 correction capacitor 15 and the horizontal deflection coil 17 are connected in series with each other, and are connected in series with the first damper diode 13 and in parallel with the second damper diode 14. ing. Furthermore, the above-mentioned first 8-figure correction capacitor 1
5 and the horizontal deflection coil 17 is the second 8
It is grounded via a character correction capacitor 16. That is, the second figure-8 correction capacitor 16 is connected in parallel to the first damper diode 13 and in series to the horizontal deflection coil 17.

In the embodiment with the above-described configuration, current flows through six closed loops as shown in the equivalent circuits of FIGS. Next winding 18
By passing a deflection current through the horizontal deflection coil 17, which is used as a choke coil, the electron beam is horizontally scanned in a cathode ray tube (not shown).

Here, the human equivalent circuit in FIG. 3 shows the operating state in the second half of the horizontal scan in this embodiment, FIG. 3B shows the operating state in the first half of the flyback period, and FIG. 3C shows the operating state in the first half of the flyback period. The second half of the operation is shown, and the third diagram also shows the first half of the horizontal scan.

That is, in this embodiment, during the second half of the horizontal scan, the transistor 11 is turned on by the horizontal drive pulse, and the first figure-8 correction capacitor 15 is charged during the first half of the horizontal scan, which will be described later. As shown in FIG. 3, the electric charge is discharged through a closed loop including the horizontal deflection coil 17, the transistor 11, and the first figure-eight correction capacitor 15, and this discharge current is applied to the horizontal deflection coil 17 as a deflection current. As I was washed away,
A drive current is supplied from the power source 20 to the primary winding 18 through a closed loop including the power source 20, the primary winding 18 of the flyback transformer 30, and the transistor 11. During the second half of this horizontal scanning, the horizontal deflection coil 17
Each current flowing through the primary winding 18 of the flyback transformer 30 increases approximately linearly with time. Further, the l transistor 11 is turned off at the end of horizontal scanning.

The horizontal deflection coil 17 and flyback transformer 3
The current flowing through the primary winding 18 of zero does not immediately become zero even when the transistor 11 is turned off, but is sustained by the electromagnetic energy of the horizontal deflection coil 17 and the primary winding 18. .

In the first half of the flyback period immediately after the transistor 11 is turned off, as shown in FIG. 3B,
A closed loop including the horizontal deflection coil 17, the resonant capacitor 12, the first damper diode 13, and the first figure-of-eight correction capacitor 15, and the flyback transformer 3.
0 primary winding 18, resonant capacitor 12 and power supply 20
A charging current flows through the resonant capacitor 12 through the closed loop including the resonant capacitor 12, and the resonant capacitor 12 is charged.

Here, the resonance capacitor 12 is charged with a high voltage due to resonance with the horizontal deflection coil 17 and the primary winding 18.

When the charging current of the resonant capacitor 12 becomes zero, the charges charged in the resonant capacitor 12ζ begin to be discharged.

In the operation in the second half of this flyback period, as shown in FIG. At the same time, the discharge current of the resonant capacitor 12 flows in a closed loop including the resonant capacitor 12, the primary winding 18 of the flyback transformer 30, and the power supply 20. That is, the discharge current corresponding to the first half of the flyback period described above is the current IHD flowing through the two closed loops to the horizontal deflection coil 17 during the second half of the flyback period.
Y and a current IFBl flowing through the primary winding 18 of the flyback transformer 30. Then, the second figure-8 correction capacitor 16 controls the current flowing through the horizontal deflection coil 17 in the second half of this flyback period.
Charged by HDY. Furthermore, when the charges stored in the resonant capacitor 12 are discharged in the second half of the flyback period and the discharge voltage decreases, the second damper diode 14 is turned on.

In the first half period of horizontal scanning when the second damper diode 14 is in the ON state, as shown in FIG. 3D,
The second damper diode 14 and the horizontal deflection coil 1
A current due to the electromagnetic energy of the horizontal deflection coil 17 flows through a closed loop including the capacitor 7 and the first figure 8 correction capacitor 15 .

The first figure-8 correction capacitor 15 is charged by the current flowing through the horizontal deflection coil 17 during the first half period of this horizontal scanning.

In this embodiment, in which horizontal scanning is performed by the operations shown in the equivalent circuits of FIGS. 3A to 3 as described above, the flyback transformer is If a high voltage load fluctuation occurs in the flyback transformer 30, for example, the load becomes heavy and the flyback transformer 3
When the current IFIII flowing through the primary winding 18 of 0 increases, the horizontal deflection coil 1 increases by the amount that this current IFBI increases.
The current I Hn y flowing through 7 will decrease. Then, in the latter half of the flyback period, the horizontal deflection coil 17
When the current I Ho y flowing through the horizontal deflection coil 17 decreases, the current flowing through the horizontal deflection coil 17 during the first half of the next horizontal scan also decreases, and the charge stored in the first figure-8 correction capacitor 15 also decreases.

Therefore, when the high voltage output decreases due to the increase in brightness in the cathode ray tube and image distortion occurs such that the image on the screen increases, the current flowing through the horizontal deflection coil 17 can be reduced to reduce the width of the image. This makes it possible to reliably correct image distortion caused by high voltage fluctuations ζ accompanying changes in the brightness level of the video signal.

Here, the second figure-of-eight correction capacitor 16 is connected in series with the horizontal deflection coil 17 in order to cause the deflection current that changes according to high voltage load fluctuations to flow through the horizontal deflection coil 17 in the latter half of the flyback period. However, as shown in FIG.
Even if it is connected in series with the horizontal deflection coil 17 via the coil 5, the same correction as in the above embodiment can be performed.

Further, the capacitance of the second figure-8 correction capacitor 16 was able to make a good correction to the capacitance of the first figure-8 correction capacitor 15.

〔Effect of the invention〕

As is clear from the description of the embodiments described above, according to the present invention, when correcting image distortion caused by high voltage fluctuations that appear asymmetrically on the left and right sides of the screen, it is possible to obtain advantages over the tertiary winding of the conventional flyback transformer. Unlike the method using retrace pulses, this method allows effective correction with an extremely simple circuit configuration, making it possible to obtain a compact and high-performance television receiver, which satisfactorily achieves the intended purpose.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of image distortion caused by high voltage fluctuations, FIG. 2 is a circuit diagram showing the circuit configuration of a specific embodiment of the present invention, and FIG. 3A is a diagram showing the horizontal scanning in the above embodiment. An equivalent circuit diagram showing the operating state in the second half, FIG. 3B, is an equivalent circuit diagram showing the operating state in the first half of the flyback period, FIG. 3C.
1 is an equivalent circuit diagram showing the operating state in the second half of the flyback period, the third diagram is an equivalent circuit diagram showing the operating state in the first half of horizontal scanning, and FIG. 4 is an equivalent circuit diagram showing the operating state in the first half of the horizontal scanning period.
− It is a circuit diagram showing the circuit configuration. 11...... Transistor 12...
... Resonance capacitor 13.14 ... Damper diode 15.16 ... Figure 8 correction capacitor 17 ... Horizontal deflection coil 1B ...
...Flyback transformer primary winding 19...
......Power input terminal 20......Power supply 30...Flyback transformer patent applicant Sony Corporation representative Patent attorney Kodo Koike 1) Mura榮 - rQrQ 閖 連, (( 00 区 区 `` 0 " 0 法 連 Ｇ Ｇ Ｇ - ~ 柟 taste 391 - く Ｇｕｍａ

Claims (1)

[Claims] A switching element connected to the power input terminal via the primary winding of the flyback transformer, a resonant capacitor connected in parallel to this switching element, and a first and second resonant capacitor connected in parallel to the switching elements connected in series with each other. a second damper diode, a first figure-eight correction capacitor and a deflection coil connected in series with each other, connected in series with the first damper diode and in parallel with the second damper diode, and the first damper diode. and a second figure-eight correction capacitor connected in parallel to the deflection coil and in series with the deflection coil and having a smaller capacitance value than the first figure-eight correction capacitor.