Bi-directional scan circuit

A bi-directional scan circuit comprising:

• a first resonance circuit comprising a series resonance circuit which comprises a first switching circuit switching on and off repeatedly at a predetermined timing, a resonance capacitor, a horizontal deflection coil and a first capacitor for forming a DC power source, and which supplies a going scan deflecting current to said horizontal deflection coil;
• a second resonance circuit comprising a series resonance circuit which comprises a second switching circuit switching on and off repeatedly with said first switching circuit complementarily, said resonance capacitor, said horizontal deflection coil and said second capacitor for power supplying having substantially the same capacitance as said first capacitor for supplying power, and which supplies a returning scan deflecting current to said horizontal deflection coil;
• a power circuit supplying driving power to said first and second resonance circuits via a series circuit of a capacitor and a coil;
• a first pin-distortion correcting circuit modulating the terminal voltage of said first capacitor for forming a direct-current power source with the first pin distortion correcting signal whose signal level varies in synchronism with the vertical synchronizing signal in parabolic shape;
• and
• a second pin-distortion correcting circuit modulating the terminal voltage of said second capacitor for forming a DC power source with the second pin-distortion signal which has an inverse polarity with respect to said first pin-distortion correcting signal and varies the signal level in a parabolic shape in synchronism with said vertical synchronizing signal;
• wherein
• said power circuit generates a modulating power source, so that its power voltage is varied by following said first pin-distortion correcting signal, and supplies said driving power, and so that the signal level is switched between said modulating power source and a "0" level in synchronism with the on-off operation of said first and second switching circuits, and is transmitted to a connection node between said resonance capacitor and said horizontal deflection coil.

A bi-directional scan circuit comprising:

• a first resonance circuit comprising a series resonance circuit which comprises a first switching circuit switching on and off repeatedly at a predetermined timing, a resonance capacitor, a horizontal deflection coil and a first capacitor for forming a DC power source, and which supplies a going scan deflecting current to said horizontal deflection coil;
• a second resonance circuit comprising a series resonance circuit which comprises a second switching circuit switching on and off repeatedly with said first switching circuit complementarily, said resonance capacitor, said horizontal deflection coil and said second capacitor for power supplying having substantially the same capacitance as said first capacitor for supplying power, and which supplies a returning scan deflecting current to said horizontal deflection coil;
• a power circuit supplying driving power to said first and second resonance circuits via a series circuit of a capacitor and a coil;
• a first pin-distortion correcting circuit modulating the terminal voltage of said first capacitor for forming a DC power source with the first pin-distortion correcting signal whose signal level changes in synchronism with the vertical synchronizing signal in a parabolic shape;
• and
• a second pin-distortion correcting circuit modulating the terminal voltage of said second capacitor for forming a DC power source with the second pin-distortion signal which has an inverse polarity with respect to said first pin-distortion correcting signal and varies the signal level in a parabolic shape in synchronism with said vertical synchronizing signal;
• wherein
• said power circuit generates a modulating power source, so that its power voltage is varied by following said first pin-distortion correcting signal with a phase which is shifted as much as a predetermined phase from the phase of said first pin-distortion correcting signal, and supplies said driving power, and so that the signal level is switched between said modulating power source and a "0" level in synchronism with the on-off operation of said first and second switching circuits, and is transmitted to a connection node between said resonance capacitor and said horizontal deflection coil.