KR970003432B1 - A device for correcting horizontal linearity in image of wide screen television - Google Patents

Abstract

None.

Description

Widescreen TV V image horizontal linearity compensation device

1 is a block diagram of a conventional image horizontal linearity compensation device.

2 is a circuit diagram of a conventional image horizontal linearity compensation device.

(A) of FIG. 3 shows a 4: 3 screen when receiving 4: 3 images, (b) shows a 16: 9 screen when 4: 3 images are received, and (c) shows a 16: 9 screen where 4: 3 Improved linearity when receiving video.

4 is a block diagram of an image horizontal linearity compensation device of the present invention.

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

6 is a circuit diagram of a second embodiment of the present invention.

7 is a characteristic diagram of current-inductance value of a saturable reactor in a second embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: CRT 2: Flyback trance

3: horizontal deflection yoke 4: horizontal deflection

5: diode modulator 6: side pincushion

7: micom 8: dummy coil switching unit

9: DC level control unit

According to the present invention, when the TV receiver having an aspect ratio of 16: 9 receives and displays an image signal having an aspect ratio of 4: 3, the horizontal linearity of the image is reduced as the screen is expanded by 33% horizontally. It relates to an image horizontal linearity compensation device of a screen TV (TV).

The wide screen TV receiver is a large TV receiver that displays images in the form of 16: 9 aspect ratio that is suitable for human visual structure. The wide screen TV receiver expands and displays 4: 3 screen to 16: 9 aspect ratio. The water receiver adopts a circuit for correcting the linearity of the image in consideration of the deflection yoke's deflection ability as the deflection angle increases, and among these linearity correction circuits, the parabolic horizontal current is applied to the deflection yoke to correct the side pincushion. Since the side pincushion correction circuit is widely applied, the configuration of the horizontal output unit to which the side pincushion circuit is applied is described with reference to FIG. 1 and a flyback transformer (2) for supplying the anode power of the CRT (1) and the flyback transformer. (2) Power is supplied from the flyback pulse generated during the return period and the horizontal drive pulse is input. A horizontal deflection portion 4 for transmitting a sawtooth deflection current to the horizontal deflection yoke 3 of the CRT 1 by switching and receiving a switching operation, and coupled with the horizontal deflection portion 4 to transmit a horizontal deflection current at a vertical period. A diode modulator 5 for modulating wave current and a side pincushion part 6 for receiving and amplifying the paraffin wave side pincushion signal and supplying it to the diode modulator 5 are as follows. same.

The flyback transformer 2 supplies the power B + supplied from the power supply unit to the horizontal deflection unit 4, and boosts the flyback pulse generated in the vertical return period of the horizontal deflection unit 4 in the secondary winding so that the CRT ( Supplying to the anode of 1), the horizontal deflection portion 4 receives a horizontal drive pulse (frequency f _H ) of 1H cycle switching operation to flow a sawtooth current through the horizontal deflection yoke (3) of the CRT (1).

In addition, the diode modulator 5 receives the output signal of the side pincushion unit 6 and modulates the horizontal deflection current of the horizontal deflection unit 4 into parablades of vertical periods to flow the side pincushion corrected horizontal deflection current. The side pincushion unit 6 receives the side pincushion signal of a 1V period and parabolically amplifies the signal to supply it to the diode modulator 5.

The side pincushion correction operation as described above will be described in more detail with reference to FIG.

In FIG. 2, Q1 is a horizontal output transistor of the horizontal deflection portion 4, D1 and D2 are damper diodes, Cy and Cy ¹ are retrace capacitors, 1y is a horizontal deflection coil, Cs is an S-shaped correction capacitor, and Lm is modulation. The output coil, Cm, is a modulation power supply capacitor, and Q2 is an output transistor of the side pincushion portion 6.

Therefore, in this circuit, the horizontal deflection coil Ly is supplied with the power supply B + voltage and the voltage Vs among the voltages Vs and Vm divided by the S-shaped correction capacitor Cs and the modulation power supply capacitor Cm, respectively. As a power source, a deflection current flows through the path of iy in the second half of the horizontal syringe, and a current flows through the deflection coil 1y through the path of -iy in the first half of the horizontal scanning period.

Then, a current flows in the path im of the second half of the horizontal scanning period with the voltage Vm charged in the modulation power capacitor Cm as a power source to the modulation output coil 1m, and a path of -im in the first half of the horizontal scanning period. Current flows.

That is, at the end of the horizontal scanning period, since the horizontal output transistor Q1 is turned off, the damper diodes D1 and D2 are turned off, and the deflection coil current iy flows through the retrace capacitor Cy, and the modulation output coil current im Flows through the retrace capacitor Cy '.

At this time, a substantially sinusoidal retrace pulse voltage is generated between both ends of the retrace capacitors Cy and Cy, and the counter electromotive force across the horizontal deflection coil 1y becomes an S-shaped correction capacitor Cs at the moment when these voltages become '0'. ), And the counter electromotive force at both ends of the modulation output coil (Lm) becomes larger than the voltage (Vm) of the modulation power supply capacitor (Cm) so that the damper diodes (D1) and (D2) are turned on and scanned again. It is a period.

At this time, the transistor Q2 is equalized with the vertical parablad period so that the modulated output coil current im flows into the vertical parablad, and the series resonance time constant of the deflection coil Ly and the S-shaped correction capacitor Cs is the horizontal frequency f. _H ) is adjusted to correct the horizontal linearity according to the wide angle and enlargement of the CRT, The deflection coil current im becomes an S-shape, and the horizontal deflection linearity of the screen is improved.

That is, there is no problem when a 4: 3 image is displayed on a 4: 3 screen as shown in (a) of FIG. 3, but when the 4: 3 image is displayed on a 16: 9 screen as shown in (b), the horizontal is described above. Since the relationship of A = B = C = D, which is a horizontal interval, is satisfied by the linearity correction, a phenomenon occurs in which the image is distorted in the form of a long horizontal stretch.

In FIG. 3 (b), the dotted circle is an image of 16: 9 and the solid circle is an 4: 3 image, and it can be seen that the circle of the solid line is long and horizontally distorted.

As described above, when a 4: 3 image is displayed on a 16: 9 screen, a conventional wide screen TV receiver has a problem that the image is distorted horizontally and thus the image quality is deteriorated and the horizontal linearity is deteriorated.

Therefore, the present invention adds a deflection dummy coil for changing the series resonance frequency of the horizontal deflection between the horizontal deflection coil and the S-shaped correction capacitor, and selectively switches the dummy coil according to an image of 4: 3, 16: 9, 9 It corrects the horizontal linearity when a 4: 3 image is displayed on the screen, and reduces the horizontal size due to the addition of the dummy coil to maintain a constant by controlling the DC level of the side pincushion output. When a wide screen TV receiver displays an aspect ratio of 4: 3, an image horizontal linearity compensation device for a wide screen TV (TV) can be used to improve horizontal linearity, improve image quality, and prevent image distortion. An object of the present invention will be described below with reference to the accompanying drawings, the configuration of the present invention and its effects.

First, referring to FIG. 4, the horizontal linearity compensator of the present invention includes a flyback transformer 2 for supplying the anode power of the CRT 1 and a return period for receiving power from the flyback transformer 2. A horizontal deflection portion 4 for supplying a flyback pulse generated at the same time and a switching operation by inputting a horizontal driving pulse to supply a sawtooth deflection current to the horizontal deflection yoke 3 of the CRT; 4) is coupled to the diode modulator (5) for modulating the horizontal deflection current into a parably wave current of the vertical period, and amplifies the side pincushion signal of the parablast wave to supply to the diode modulator (5) The side pincushion part 6, the microcomputer 7 which controls the dummy coil switching part 8 and the DC level control part 9 according to the aspect ratio, and the horizontal direction of the CRT 1 in the horizontal deflection part 4 Supplied to the deflection yoke (3) The dummy coil switching unit 8 which changes the series resonance frequency of the flat deflection current to the aspect ratio under the control of the microcomputer 7, and the DC level of the side pincushion unit 6 under the control of the microcomputer 7. It consists of a DC level control unit 9 for adjusting the increase / decrease according to the aspect ratio, the operation is as follows.

The flyback transformer 2 supplies the power B + supplied from the power supply unit to the horizontal deflection unit 4, and boosts the flyback pulse generated in the vertical return period of the horizontal deflection unit 4 in the secondary winding so that the CRT ( Supplying to the anode of 1), the horizontal deflection portion 4 receives a horizontal drive pulse (frequency f _H ) of 1H cycle switching operation to flow a sawtooth current through the horizontal deflection yoke (3) of the CRT (1).

At this time, the series resonant frequency of the current flowing through the deflection coil of the water deflection yoke 3 in the horizontal deflection portion 4 is controlled by the dummy coil switching unit 8 which is operated under the control of the microcomputer 7.

That is, when the 4: 3 image is displayed on the 16: 9 screen, the micro coil 7 operates the dummy coil switching unit 8, and correspondingly, the dummy coil switching unit 8 controls the horizontal deflection unit 4. The inductance value for determining the horizontal deflection series resonant frequency is increased, and accordingly, the horizontal resonant frequency decreases as the inductance value increases from the equation of the resonance frequency.

As the horizontal resonant frequency decreases, the S-correction curve is adjusted, so that as the horizontal interval of the 4: 3 image displayed on the 16: 9 screen is moved from the center of the screen to both ends as shown in (c) of FIG. The relation of widening A <B <C <D is satisfied, and the horizontal linearity is improved as an example of an image represented by a solid circle.

In addition, the diode modulator 5 receives the output signal of the side pincushion unit 6 and modulates the horizontal deflection current of the horizontal deflection unit 4 into parablades of vertical periods to flow the side pincushion corrected horizontal deflection current. The side pincushion unit 6 receives the side pincushion signal of 1V period and parabolically amplifies the signal to supply the diode modulator 5.

At this time, as the inductance value of the horizontal deflection series resonant frequency is increased by the dummy coil switching unit 8, when the horizontal frequency is lowered, the horizontal size is reduced.

The reduction of the horizontal size is caused by changing the DC level of the side pincushion unit 6 when the 4: 3 image is displayed on the 16: 9 screen under the control of the microcomputer 7 by the serial level adjusting unit 9. The output signal of the side pincushion section 6 whose level is changed causes the horizontal parabolic direct current level of the diode modulating section 5 to be restored to its original size.

FIG. 5 shows a circuit diagram of the first embodiment of the present invention, wherein the dummy coil switching unit 8 includes a dummy coil Ld connected in series with a horizontal deflection coil Ly and an S-shaped correction capacitor Cs, and the dummy coil Ld. The first switching element Q3 for changing the series resonance inductance value by connecting or disconnecting the coil Ld, and the second switching element for turning on / off the switching element Q3 under the control of the microcomputer 7. (Q4) and bias resistors R1, R2, and R3 for biasing the switching element, and the DC level adjusting unit 9 divides the power supply VC1 voltage to the side pincushion unit. Under the control of the resistors R6, R7, R8 and the microcomputer 7, which sets the DC level of (6), it is turned on / off by the resistors R6, R7, R8. And a third switching element Q5 for changing the DC bias, and resistors R4 and R5 for biasing the switching element.

The first switching element Q3 is configured as an N-channel MOS FET, and the second switching element Q4 and the third switching element Q5 are configured by a transistor.

The horizontal linearity compensation operation according to the first embodiment of the present invention configured as described above is as follows. Q1 is a horizontal output transistor of the horizontal deflection portion 4, D1 and D2 are damper diodes, and Cy, Cy 'is Return capacitor, Ly is horizontal deflection coil, Cs is S-shaped correction capacitor, Lm is modulation output coil, Cm is modulation power supply capacitor, Q2 is output transistor of side pincushion section 6, A1 is op amp, R9, R10 is resistor to be.

Therefore, in this circuit, the horizontal deflection coil Ly is supplied with the power supply B + voltage and the voltage Vs among the voltages Vs and Vm divided by the S-shaped correction capacitor Cs and the modulation power supply capacitor Cm, respectively. As a power source, a deflection current flows through the path of iy in the second half of the horizontal scanning period, and a current flows through the deflection coil Ly in the path of -iy in the first half of the horizontal scanning period.

The modulated output coil Lm uses (Vm) charged to the modulation power supply capacitor Cm as a power source, and current flows through the path of im in the second half of the horizontal syringe, and the path of -im in the first half of the horizontal scanning period. Current flows

When the 16: 9 image is displayed on the 16: 9 screen, the microcomputer 7 outputs a low signal at the output terminal, and the second switching element Q4 is turned off by the low signal. ) Is turned on, and both ends of the dummy coil Ld are short-circuited when the first switching element Q3 is turned on, so that the dummy coil Ld is separated from the deflection coil Ly and the S-shaped correction capacitor Cs, thereby deflecting the coil ( Ly) and the S-shaped correction capacitor Cs are connected in series through the first switching element Q3.

Therefore, at the end of the horizontal scanning period, the horizontal output transistor Q1 is turned off, so the damper diodes D1 and D2 are turned off, and the deflection coil current iy flows through the retrace capacitor Cy, and the modulation output coil current im Flows through the retrace capacitor Cy '.

At this time, a substantially sinusoidal retrace pulse voltage is generated between both ends of the retrace capacitors Cy and Cy, and the counter electromotive force across the horizontal deflection coil Ly becomes an S-shaped correction capacitor Cs at the moment when these voltages become '0'. ), And the counter electromotive force at both ends of the modulation output coil Lm becomes larger than the voltage Vm of the modulation power supply capacitor Cm so that the damper diodes D1 and D2 are turned on and scanned again. It is a period.

The side pincushion section 6 receives a side pincushion signal, which is supplied to the inverting input terminal (-) of the operational amplifier A1 and amplified by the gains R10 and R9 set by the resistors R9 and R10. And output, and the transistor Q2 is operated by the amplified signal.

At this time, a DC bias level is input to the non-inverting input terminal (+) of the operational amplifier A1. As described above, when a low signal is output from the output terminal of the microcomputer 7, the third switching element of the DC level adjusting unit 9 ( Since Q5) is off, the DC bias level is determined as VCC1 * (R7 + R8) / (R6 + R7 + R8) so that the DC signal of this level is input to the inverting input terminal of the operational amplifier A1 as described above. Amplified together with the signal is applied to the base of the transistor Q2, thereby determining the direct current level of the modulation power supply capacitor (Cm).

The transistor Q2 is operated in a vertical parablade period so that the modulated output coil current im flows into the vertical parablad. The horizontal deflection coil Ly is a deflection coil Ly and an S-shaped correction capacitor Cs in the sawtooth deflection current. The series resonant currents of supersedes and the series resonant time constant is tuned to the horizontal frequency (f _H ) to compensate for the horizontal linearity due to wide-angle and enlargement of the CRT. The deflection coil current im becomes an S-shape, and the horizontal deflection linearity of the screen is improved, and as shown by the dotted line in FIG.

On the other hand, when a 4: 3 image is displayed on the 16: 9 screen, the high signal is output from the output terminal of the microcomputer 7.

When the high signal is output from the microcomputer 7, the second switching element Q4 is turned on and thus the first switching element Q3 is turned off, so that the dummy coil Ld is configured to have a deflection coil Ly and an S-shaped correction capacitor Cs. ) Is connected in series to increase the series resonance inductance value.

Ie the horizontal frequency in this case The series resonant frequency decreases because the inductance value is increased, and the horizontal deflection current is in series with the inductance value of the horizontal deflection coil Ly and the dummy coil Ld in the sawtooth deflection current. As the resonant currents are superimposed and the frequency of the series resonant currents is reduced as described above, as shown in (c) of FIG. 3, the center portion of the screen is narrow and the deflection distance relationship gradually increases toward both ends, A <B <C <D By satisfying the horizontal linearity is improved.

On the other hand, the high signal output from the microcomputer 7 turns on the third switching element Q5 of the DC level adjusting unit 9 so that both ends of the resistor R8 are short-circuited and applied to the non-inverting input terminal of the operational amplifier A1. The losing DC level is set to VCC * R7 / (R6 + R7), and this DC voltage is applied to the inverting input terminal of the operational amplifier A1 and applied to the base of the transistor Q2 together with the inverted and amplified signal.

Therefore, the DC level of the modulation power capacitor Cm is changed by the transistor Q2, and this voltage is lowered to compensate for the reduction in the horizontal size due to the addition of the horizontal deflection dummy coil Ld. Likewise, as the series resonance frequency decreases, the horizontal size is reduced and the distortion of the image is horizontally corrected so that a high quality image can be expressed.

FIG. 6 is a circuit diagram showing a second embodiment of the present invention. Referring to FIG. 6, the dummy coil switching unit 8 includes a horizontal deflection coil Ly and an S-shaped correction capacitor Cs in the secondary side. The connected saturable reactor T1, the fourth switching element Q7 which changes the series resonance inductance value by changing the primary side current of the saturable reactor T1, and the switching under the control of the microcomputer 7. And a fifth switching element Q6 for turning on / off the element Q7, and bias resistors R11, R12, R13, R13, R14, and R15 for biasing the switching element. The fourth and fifth switching elements Q7 and Q6 are composed of transistors, and the same components as those of the first embodiment are denoted by the same reference numerals, and descriptions of overlapping configurations and operations are omitted.

In the second embodiment of the present invention configured as described above, as shown in FIG. 7, the inverse characteristic of the secondary inductance value Ls according to the primary side current Ip of the saturable reactor T1 is used.

That is, when the 16: 9 image is displayed on the 16: 9 screen, a low signal is output from the output terminal of the microcomputer 7 so that the fifth switching element Q6 is turned off, so that the fourth switching element Q7 is a resistor R13. The primary side current Ip of the saturable reactor T1 increases due to the bias currents determined by (), (R14), and (R15), and as a result, the saturable reactor T1 is shown in FIG. Since the secondary side inductance value Ls is reduced, the series resonance frequency f _H of the horizontal deflection coil Ls and the S-shaped correction capacitor Cs at this time increases.

However, when the 4: 3 image is displayed on the 16: 9 screen, the high signal is output from the output terminal of the microcomputer 7 and the fifth switching element Q6 is turned on, so that the resistor R12 is parallel to the resistor R14. In this case, the current Ip flowing to the primary side of the saturable reactor T1 decreases according to the bias change applied to the fourth switching element Q7.

When the current Ip flowing to the primary side of the saturable reactor T1 decreases, the secondary inductance value Ls increases as shown in FIG. 7, so that the horizontal deflection coil Ls and the S-shaped correction capacitor Cs are reduced. As the series resonance frequency of is reduced, the horizontal linearity is compensated as described above.

As described above, according to the present invention, a 16: 9 wide screen TV improves the horizontal linearity of the image when the 4: 3 image is displayed on the receiver and prevents horizontal distortion, thereby ensuring high quality image representation. In this way, there is an effect that can improve the quality of the device accordingly.

Claims (4)

The flyback transformer (2) for supplying the anode power of the CRT (1), the flyback transformer (2) is supplied with power and the flyback pulse generated during the return period, while receiving a horizontal drive pulse and switching operation And a horizontal deflection portion 4 for passing a sawtooth deflection current to the horizontal deflection yoke 3 of the CRT 1 and the horizontal deflection portion 4 so as to modulate the horizontal deflection current into a vertical parabolic current. The diode modulator 5, the side pincushion part 6 which receives the paraffin wave side pincushion signal and amplifies it and supplies it to the diode modulator 5, and the dummy coil switching part 8 according to the aspect ratio. And a series resonant frequency of the microcomputer 7 for operating the DC level control unit 9 and the horizontal deflection current supplied from the horizontal deflection unit 4 to the horizontal deflection yoke 3 of the CRT. 7, control A dummy coil switching unit 8 that receives and changes the aspect ratio, and a DC level adjusting unit 9 that increases or decreases the DC level of the side pincushion unit 6 according to the aspect ratio under the control of the microcomputer 7. Image horizontal linearity compensation device of a wide screen TV (TV). 2. The DC level control unit 9 according to claim 1, wherein the DC level adjusting unit 9 divides the voltage of the power supply VC1 to set the DC level of the side pincushion unit 6, R6, R7, R8, and microcomputer. A third switching element Q5 for turning on / off under the control of (7) to change the direct current bias by the resistors R6, R7, and R8, and a resistor for biasing the switching element ( R4) and (R5), the image horizontal linearity compensation device of a wide screen TV (TV). The dummy coil switching unit 8 is configured to connect or disconnect a dummy coil Ld connected in series with a horizontal deflection coil Ly and an S-shaped correction capacitor Cs, and the dummy coil Ld. The first switching element Q3 for changing the series resonance inductance value, the second switching element Q4 for turning on / off the switching element Q3 under the control of the microcomputer 7, and the switching. An image horizontal linearity compensator for a wide screen TV composed of bias resistors R1, R2, and R3 that bias the device. 2. The dummy coil switching unit (8) according to claim 1, wherein the dummy coil switching unit (8) comprises a saturable reactor (T1) connected in series with a horizontal deflection coil (Ly), an S-shaped correction capacitor (Cs), and a secondary side thereof, and the saturable reactor (T1). A fourth switching element Q7 for varying the series resonance inductance value by changing the primary side current of the second current; and a fifth switching element for turning on / off the switching element Q7 under the control of the microcomputer 7. Q6) and a wide screen TV (TV) image horizontal linearity compensating device composed of bias resistors (R11), (R12), (R13), (R14), and (R15) for biasing the switching element.