JPS59125175A - Compensating circuit of deflection distortion - Google Patents

Abstract

PURPOSE:To compensate assuredly and effectively the vertical keystone distortion on the screen of a CRT by generating a magnetic flux at a deflecting yoke in response to the difference between the currents flowing to the 1st and 2nd inductances. CONSTITUTION:The sawtooth wave power supply which varys in a vertical deflection cycle with phases opposite to each other is given to power supply input terminals 11 and 21. Thus transistors 14 and 24 are switched at a horizontal deflection cycle, and therefore the sawtooth wave current IL1 and IL2 of a horizontal deflection cycle having the wastooth wave envelope curve of a vertical deflection cycle with inclination copposite to each other is conducted to inductances 12 and 22 respectively. The difference current ICP between both inductances is conducted to the primary sice coil 30P of a transformer 30; while a current IVDC obtained by superposing the compensated current ICP on the vertical deflection driving current IVD is conducted to a vertical deflecting coil 50 connected in series to the secondary side coil 30S. As a result, a magnetic flux is generated at a vertical deflecting yoke in response to the current ICP. Thus the vertical keystone distortion is compensated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a deflection distortion correction circuit applied to an electron beam deflection system in a cathode ray tube. This invention relates to a deflection distortion correction circuit.

[Background technology and its problems]

Conventionally, the widely known cathode ray tube has an electron gun 1 disposed perpendicular to a fluorescent surface 2, as shown in FIG. The emitted electron beam BE is deflected and scanned by a polarization system 3. In the conventional general cathode ray tube as described above, it is known that upper and lower bin distortion D + · as shown in FIG. 2 occurs as deflection distortion in the vertical direction of the screen. The above-mentioned upper and lower pin distortion D p has been corrected in the deflection system by directly passing a horizontal parabolic current corresponding to .

In the above-mentioned method of correcting deflection distortion by directly passing a horizontal deflection current through the vertical deflection coil, the power supply voltage must be increased when the correction lid is large, and the amount of correction cannot be increased very much. In addition, in the method of using a saturable transformer, the core is saturated, so the loss increases as the amount of correction increases, and the bias must be set at the saturation point, so it is necessary to consider the effects of self-inductance, etc. This has the disadvantage that the degree of freedom in design is reduced.

By the way, when the cathode ray tube is made into a flat shape by arranging the electron gun 5 horizontally with respect to the fluorescent surface 4 as shown in FIG. When the gun 5 is placed in the horizontal deflection direction of the electron beam box, vertical keystone distortion D+< as shown in FIG. 4 occurs as deflection distortion in the vertical direction of the screen.

Large upper and lower key distortion DK as shown in Figure 4 above
is extremely difficult to correct efficiently and accurately using the conventional methods described above.

[Object of the Invention] Accordingly, the present invention provides a deflection distortion correction circuit that can efficiently and reliably correct the vertical keystone distortion occurring in the screen of a cathode ray tube.

[Summary of the invention]

In order to achieve the above-mentioned object, the deflection distortion correction circuit according to the present invention includes a first switching element and a first visual inductance connected in series between a first current input terminal and ground, and has a horizontal deflection period. It consists of a first sawtooth wave current generator that generates a sawtooth wave current of, a second switching element and a second inductance connected in series between a second power input terminal and ground, and a horizontal deflection period. a second sawtooth wave current generator that generates a sawtooth current, and supplies a sawtooth wave power source that changes with a vertical deflection period to at least one of the first power input terminal or the second power input terminal. , the vertical deflection yoke is characterized in that a magnetic flux is generated in the vertical deflection yoke according to the difference between the currents flowing through the first inductance and the second inductance.

〔Example〕

Hereinafter, one embodiment of the deflection distortion correction circuit according to the present invention will be described in detail with reference to the drawings.

FIG. 5 is a circuit diagram showing a first embodiment of the present invention.

In this embodiment, the first power input terminal 11 and the second power input terminal 21 are supplied with sawtooth wave power supplies ES□ and Es2 whose power supply voltages change in opposite phases to each other with a vertical deflection period Tv. .

A first inductance 12 and a capacitor 13 are connected in series between the first power input terminal 11 and the ground, and a first Nl'Nl-transistor for switching is connected to the capacitor 13. 14 are connected in parallel. The first NPN transistor 14 has a horizontal side motion signal 1. ．． By applying II), a switching operation is performed at the horizontal deflection period TH, thereby forming a first sawtooth wave current generator which generates the sawtooth wave current at the horizontal deflection period To.

Moreover, between the second power input terminal 21 and the ground,
A second inductance 22 and a capacitor 23 are connected in series, and a second NPN transistor 24 for switching is connected in parallel to the capacitor 23. The second NPNI transistor 24 is a second sawtooth current generator that performs a switching operation in phase with the first NPNI transistor 14 and generates a sawtooth current with a horizontal deflection period of 1'n. It consists of

Furthermore, the first inductance 12 and the first NPN
The connection point A1 of the transistor 4 is connected to the second inductance 22 through a series circuit of the primary coil 30p of the trans/)' 2 NpN
It is connected to the connection point A2 of the l-transistor 24. And the secondary coil of the above I-Lance 20! 2O5 is
Vertical deflection drive current ■vD input terminal 41 and output terminal 42
is connected to the vertical deflection coil 50 via the output terminal 42.

In the first embodiment having the above-described configuration, each power input terminal 11.21 is provided with a sawtooth wave power source BSr of opposite phase,
Since ES2 is supplied, each transistor 14.2
4 performs an in-phase switching operation with a horizontal deflection period To, and as shown in FIGS. Sawtooth current LLI with deflection period T11
, IL2 flows into the first inductance 12 and the second inductance 22. Therefore, the transformer 30
In the primary coil 30p, as shown in FIG. 6C, each current 1, r
A current of 1 cp, which is the difference between r II and 2, flows. Zunaichi, vertical deflection period Tv with sawtooth wave horizontal deflection period IJt
A correction current 1 cP multiplied by a sawtooth wave of , , flows through the negative side coil 30p. A current 1 voc as shown in the sixth diagram, in which the correction current Icp is superimposed on the vertical deflection drive current IV11, flows through the vertical deflection coil 50 connected in series to the secondary coil 30s of the transformer. Therefore, in the vertical deflection yoke provided with the &i& deflection coil 50, the correction current 1c+, i.e., the currents I+, +, II, flowing through the inductances 12, 22,
A magnetic flux corresponding to the difference between the two is generated, and the above-mentioned vertical keystone distortion can be corrected. In the first embodiment described above, the resistor 41 connected in series to the negative side coil 40p of the transformer 4° blunts the sawtooth wave of the horizontal deflection period as shown by the valley line in FIG. This is to perform vertical barrel correction of the screen.

Furthermore, although the inductances 32 and 33 in the first embodiment described above are formed individually, they may also be formed using a transformer having a common core, a horizontal deflection coil, or the like. Further, in the first embodiment described above, the vertical deflection coil 50 is connected in series to the secondary coil 30s, and the primary coil 30P is provided between the first inductance 12 and the second inductance 22. However, as in the second embodiment shown in FIG. 8, the primary coil 30s is divided and the first inductance 12 is connected to the first power supply via one primary coil 60Pl of the transformer 6υ. Input terminal 11
and connect the second inductance 22 to the transformer 6.
Even with a configuration in which the second power supply input terminal 21 is connected to the second power input terminal 21 via the other primary coil 60P2 of 0, the same correction operation as in the first embodiment described above can be performed. Here, each secondary coil 60 of the transformer 6U in the second embodiment
1.l.

601=2 are wound in opposite directions. In addition,
In this second embodiment, an inductance 71.81 and a capacitor 72.8 connected to each power input terminal 11, 21 are used.
The vertical/lull distortion can be corrected by a time constant of 2.

Next, in the third embodiment shown in FIG. 9, the first power input terminal 11 is supplied with a sawtooth wave power source Eδ whose voltage changes with the vertical deflection period Tv, and the second power input terminal The terminal 21 is supplied with a constant voltage power Ec. A connection point a1 between the first inductance 12 and the capacitor 13 and a connection point a2 between the second inductance 22 and the capacitor 23 are connected via a balance capacitor 91 to prevent backflow. N1 for switching via tie auto 92.93 for
-'Nl- Commonly connected to transistor 94. The above N I) N l-ranjisk 94 receives the horizontal drive signal Ho.
By performing the switching operation by A magnetic flux corresponding to the difference can be generated in the vertical deflection yaw.

〔Effect of the invention〕

As is clear from the description of the embodiments described above, the deflection distortion correction circuit according to the present invention can efficiently and accurately correct vertical keystone distortion with a large distortion rate without using a special transformer such as a saturable transformer. It is possible to fully achieve the intended purpose.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the structure of a general cathode ray tube, and FIG. 2 is a schematic diagram showing the upper and lower bin distortions that occur in the cathode ray tube. FIG. 3 is a schematic diagram showing the structure of a cathode ray tube equipped with an electron gun in the horizontal deflection direction, and FIG. 4 is a schematic diagram showing the vertical keystone distortion occurring in the cathode ray tube. FIG. 5 is a circuit diagram showing the first embodiment of the present invention, and FIG. 6 is a waveform diagram for explaining the correction operation of the upper and lower key distortion in the first embodiment. , and FIG. 7 are waveform diagrams for explaining the correcting operation of the vertical barrel distortion in the first embodiment. FIG. 8 is a circuit diagram showing a second embodiment of the present invention. FIG. 9 is a circuit diagram showing a third embodiment of the present invention. 11.21......Power input terminal 12.22
......Inductance 14.24.94・
・・・・・・Transistor for switching 30.60・
・・・・・・・・・1゛Lance 50・・・・・・・・・
・・・・・・Vertical deflection coil patent applicant Nony Co., Ltd. Representative Patent attorney Akira Koike 1) Sakae Haku - 1F, Figure 1 Figure IF-2. , 1 36 Figure 0 Figure 6 Figure 71! l 8th evil

Claims (1)

[Claims] a first sawtooth wave current generator, which is composed of a first Swiss chinking element and a first inductance connected in series between a first power input terminal and ground, and generates a sawtooth wave current with a horizontal deflection period; , a second sawtooth wave current generator comprising a second inductance and a second inductance connected in series between the second power input terminal and ground, and generating a sawtooth current with a horizontal deflection period. , supplying a sawtooth wave power that changes with a vertical deflection period to at least one of the first O) power input terminal or the second power input terminal, and responding to the difference between the current flowing through the first inductance and the second inductance. 1. A deflection distortion correction circuit characterized in that a vertical deflection yoke generates a magnetic flux generated by a vertical deflection yoke.