JP3143211B2 - Left and right pincushion distortion correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pincushion distortion correcting device for a television receiver or the like.

[0002]

2. Description of the Related Art Conventionally, lateral distortion (disturbance) in a CRT of a television receiver or a display device is mainly caused by (a) curvature of the CRT (a) disturbance of a magnetic field of a deflection yoke. Some are due to

[0003] (A) is a so-called pincushion distortion, left and right (right half and left half of the CRT screen) and upper,
It occurs symmetrically below and there is little variation between receivers (between sets). In addition, (a) is not necessarily symmetrical because the magnetic field distribution of the deflection yoke is disturbed, and there is much variation between sets.

In recent years, a non-spherical CRT having a flat central portion of a face plate is used in a recent image receiver or the like. This CRT has a larger pincushion distortion at the central portion than a conventional spherical CRT. This tends to reduce pincushion distortion in the peripheral portion.

The conventional left and right pincushion distortion correction device is adapted to the above-mentioned aspherical CRT.
As described in the publication No. 77661 (H04N 3/23) and the like, the amount of signal feedback at the time of forming a parabolic wave voltage for pincushion distortion correction by integrating a vertical sawtooth voltage is varied, and the correction is performed by this variable. The current flowing in the horizontal deflection coil of the horizontal output circuit is modulated with the vertical cycle by the parabolic wave voltage thus obtained.

[0006]

In the case of the above-mentioned conventional correction device, the amount of correction is adjusted stepwise in accordance with the magnitude of the parabolic wave voltage by switching of a zener diode or a diode, so that the correction characteristic is low. There is a problem that it is not only vertically symmetrical, and in particular, it is not possible to correct the vertically asymmetrical distortion of the above (a).
T of the entire screen of the left and right pincushion distortion accurate correction of a problem can not be performed.

The present invention relates to a CRT including the distortion (a).
It is an object of the present invention to provide a left and right pincushion distortion correction device capable of accurately correcting left and right pincushion distortion of the entire screen .

[0008]

To SUMMARY OF THE INVENTION To achieve the above object, in the left and right pincushion distortion correction apparatus of the present invention, the every vertical period based on the vertical sync signal into a plurality of correction sections divided
Then, at the timing of screen scanning in each of the correction sections, each of the corrections is performed.
A correction interval setting unit that forms a positive section selection signal of the respective correction amount adjustment voltage, a plurality of setting conductive by the respective selection No.択信
Alternatively selected voltage from pressure, or a plurality of voltages selected from the respective set voltage by the selection signal via a resistor
The integration smoothed voltage of the parallel combined voltage, the correction amount adjusting electrostatic
A correction amount adjusting unit that superimposes the pressure on the parabolic wave voltage.

[0009]

In the correction apparatus of the present invention having the above-described configuration, the correction section setting section corrects each correction section obtained by dividing the entire screen in the vertical direction in accordance with scanning of the CRT screen.
A selection signal for the quantity adjustment voltage is formed.

Furthermore, the voltage selection of based rather correction amount adjuster to these selection signals, superimposes the voltage to the parabolic wave voltage to form a correction amount adjusting voltages of each correction interval, Pas Laboratories wave voltage adjusted to each of the correction amount with respect to the distortion
Adjust for each correction section .

[0011] The entire CRT screen has a plurality of vertical
Is divided into the correction section, moreover, it is possible to freely set the correction amount adjustment voltage for each of these correction interval, correction of vertically asymmetric distortion there are variations between sets are lines Ukoto is
To correct the pincushion distortion of the entire CRT screen with high accuracy.
The correction accuracy can be significantly improved by making the correction section finer.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS.

(First Embodiment) First, one embodiment will be described with reference to FIGS. In FIG. 1, reference numeral 1 denotes an input terminal of a horizontal drive signal, and 2 denotes a horizontal output circuit having various diode modulation circuits. As in the circuit described in the above publication, a horizontal output transistor Q1 and damper diodes D1, D
2. Retrace capacitances C1 and C2, primary winding L1 of horizontal output transformer, horizontal deflection coil L2, S-shaped correction capacitor C
3. Consists of a modulator coil L4 and a modulator capacitor C4.

Reference numeral 3 denotes a vertical output circuit, L4 denotes a vertical deflection coil, C5 denotes a vertical coupling capacitor, R1 denotes an AC feedback resistor, C6 denotes a coupling capacitor, 4 denotes a vertical sawtooth voltage input terminal, and 5 denotes a parabolic wave voltage generation. And a variable resistor VR1 and a capacitor C for the Miller integrating circuit.
7, a DC feedback resistor R2, a variable resistor VR for adjusting a DC output voltage, a drive transistor Q2 for inverting amplification, an output transistor Q3, a choke coil L4, a base input resistor R3, and a bias resistor R4.

Reference numeral 6 denotes an input terminal of the vertical synchronizing signal Sv, 7A denotes a correction control unit, which comprises a correction section setting unit 8A and a correction amount adjustment unit 9A. The setting unit 8A is composed of five monostable multivibrators (hereinafter referred to as monomultivibrators). The adjustment unit 9A is formed by a cascade circuit of 10a to 10e and two NAND gates 11a and 11b, and an adjustment unit 9A includes an analog switch circuit 12 of a model number PD4051B, five variable resistors VR3 to VR7 for setting a correction amount adjustment voltage, and a voltage division Are formed by the resistors R5 and R6.

In the figure, + B and Vcc are positive DC bias power supply terminals, and -B is a negative DC bias power supply terminal. In the analog switch circuit 12, A, B, and C are control terminals, X is an output terminal, INH is a prohibition gate terminal for prohibiting high-level active operation, and X0 to X7.
Is an input terminal which is alternatively selected and connected to the output terminal X.

Then, the input terminal 1 is input from the horizontal drive circuit.
Output circuit 2 by the horizontal drive signal supplied to the
The horizontal output transistor Q1 is switched, and this switching causes a horizontal period sawtooth current to flow through the deflection coil L2 and a high voltage output current to flow through the primary winding L1 of the output transformer.

Further, the vertical output circuit 3 supplies the deflection coil L4
Is supplied to the input terminal 4 based on the vertical deflection current supplied to the input terminal 4, and the voltage V 1 is supplied to the correction circuit unit 5.
Is subjected to Miller integration and inverted and amplified.

The parabolic wave voltage V2 for correcting pincushion distortion is formed by this inversion amplification, and this voltage V2 is supplied to the horizontal output circuit 2 via the choke coil L4. Then, the current flowing through the deflection coil L2 is modulated in the vertical cycle by the parabolic wave voltage V2, and the pincushion distortion is corrected.

However, simply forming the parabolic wave voltage V2 by mirror integration of the vertical sawtooth voltage V1 causes inconveniences such as the inability to correct vertically asymmetric distortion as described in the conventional example. Therefore, in this embodiment, the correction control unit 7A
To adjust the parabolic wave voltage V2 as described below.

First, the vertical synchronizing signal Sv having the pulse width τv shown in FIG. 2A is supplied from the input terminal 6 to the mono-multi 10a, and the mono-multis 10a to 10e are sequentially triggered. At this time, the outputs Sa to Sd of the mono multis 10a to 10d
Fall in synchronism with the rising edges of the inputs (= Sv, Sa, Sb, Sc) as shown in FIGS. 2B to 2E, and generate low-level pulses having pulse widths τa to τd.

The output Se of the mono-multi 10e is shown in FIG.
(F), the signal rises in synchronization with the fall of the input (= Sd) and generates a high-level pulse having a pulse width τe. Further, the outputs Sb and Sd are supplied to the NAND gate 11a, and the outputs Sc and Sd are supplied to the NAND gate 11a.
b and outputs Sf, S of both gates 11a, 11b.
g becomes as shown in (g) and (h) of FIG.

The outputs Se, Sf and Sg formed based on the vertical synchronizing signal Sv are determined by a combination of their high level ("1") and low level ("0").
CRT screen divided into vertical periods (one screen)
Τv + τa, τb, τc, τ obtained by dividing the whole in the vertical direction
It becomes a selection signal of the correction amount adjustment voltage in each of the five correction sections of d and τe.

This selection signal, that is , the screen of each correction section
Outputs Se, Sf, and Sg formed at the timing of scanning are supplied to the control terminals C, A, and B of the switch circuit 12.
Between the input terminals X0 to X4 to which R3 to VR7 are connected and the output terminal X are selectively turned on in accordance with screen scanning.

[0025] Then, set the voltage of the alternative on the selected input terminal, for example, a variable resistor VR3 voltage input terminal X0 set in the input terminal X0, the resistors R5, R6 via the output terminal X Connect the correction amount adjustment voltage to the connection point.
Ru is output Te.

The output Sx of the adjustment voltage is applied to the base of the transistor Q2 of the correction circuit unit 5 via the resistor R6, and the correction amount adjustment voltage is multiplexed with the parabolic wave voltage based on the vertical sawtooth voltage V1.

Then, selection is made by a selection signal of each correction section.
The multiplex of correction amount adjustment voltage, the parabolic wave voltage V2 to be supplied to the deflection circuit 2 according to the scanning of C RT screen, appropriate adjustment of the correction amount of the correction section is performed. When the parabolic wave voltage based on the vertical sawtooth voltage shown in FIG. 3A is a solid line in FIG. 3B, an example of the output Sx and an adjustment characteristic based on the output Sx will be described below. Become.

That is, (c), (d) and (e) of FIG.
The variable resistors VR3 to VR7 are selectively selected based on the combination of the signals of the control terminals A, B, and C shown in FIG.
The output Sx in the vertical period 1V changes according to the correction section as shown in FIG. Then, by the change of the output Sx according to the correction section, the parabolic wave voltage (parabolic wave voltage before adjustment) indicated by the solid line in FIG. 3B is divided for each correction section, and the correction amount is individually adjusted. The parabolic wave voltage V2 shown by the broken line in FIG.

Based on the corrected parabolic wave voltage V2, for example, as shown on the CRT screen 13 in FIG. 4, the distortion that is corrected only to the extent indicated by the solid line in the uncorrected parabolic wave voltage is indicated by the broken line in FIG. As described above.

[0030] This parabola wave voltage, in accordance with the screen scan of each correction interval obtained by dividing the entire screen in the vertical direction, the correction interval it set by the variable resistor VR3~VR7
Is because that is adjusted by the correction amount adjustment voltage of respective appropriately sized, the correction of the vertically asymmetric vertical line distortion there are variations between sets was not possible prior This adjustment is also performed. In addition, as is clear from the broken line in FIG.
Since the output Sx is integrated and smoothed by the correction circuit unit 5, the boundary of the correction on the CRT screen based on the stepwise difference of the correction amount adjustment voltage becomes inconspicuous.

(Other Embodiment) Next, another embodiment will be described with reference to FIGS. FIG. 5 shows a circuit unit corresponding to the correction control unit 7A of FIG. 1. Reference numeral 7B denotes a correction control unit, which includes a correction section setting unit 8B and a correction amount adjustment unit 9B. 13 is an input terminal for the horizontal synchronization signal Sh, and 14 is an input terminal for the vertical synchronization signal Sv.

The correction section setting unit 8B includes three cascade-connected flip-flops (hereinafter referred to as FFs) 15a to 15c for counting the horizontal synchronizing signal Sh and the NOR gate 1.
6, Programmable 4-bit synchronous counter circuit 17, model number 74HC161, inverters 18, 19, frequency dividing F
F20 comprises four OR gates 21a to 21d.

Further, the correction amount adjusting section 9B has a model number μPD40.
51B, four analog switch circuits 22a to 22d,
Eight variable resistors VR8 to VR15, V for correction amount setting
R16 to VR23, VR24 to VR31, VR32 to V
R39, output resistors R7 to R10, coupling resistor R
11 to R13 and an integrating capacitor C8.

The cascaded FFs 15a to 15c have their inverted output terminals Q ^* connected to the respective data input terminals D to form a 1/2 frequency divider, and the input terminals 14 shown in FIG. The vertical synchronizing signal Sv is supplied to the low-level active clear terminal CLR, and is cleared and reset when the leading edge of the vertical synchronizing signal Sv falls.

Further, the horizontal synchronizing signal S of the input terminal 13
h, the output of the non-inverting output terminal Q of the preceding FF 15a, 15b is supplied to the clock terminal CK of the FF 15a-15c, and the output of the output terminal Q of each FF 15a-15c is the signal S
Inversion is repeated at a cycle of 2, 4 and 8 times v.

The output of the output terminal Q of each of the FFs 15a to 15c is supplied to the NOR gate 16, and the gate 16
The output S ₁₆ of FIG.
Each time a pulse is counted, it becomes a high-level pulse for one horizontal period.

The output S ₁₆ of the gate 16 is supplied to a clock terminal CK of the counter circuit 17, this time, the counter circuit 17 is an input terminal A of the preset data, B, C,
D is grounded to a low level, and the load input terminal LD, the count enable terminal EP, and the count disable terminal ET are both pulled up to a high level, and set to the counting state of the rising edge of the pulse applied to the clock terminal CK. You.

[0038] Then, the output terminal QA of the least significant bit of the 4 bits of the order of the counter circuit 17 by the pulse count of the output S _16, QB, QC, QD of the output SA, SB, SC, S
D changes as shown in (c), (d), (e), and (f) of FIG. 6 to form a 4-bit binary count value that increases by one for every eight pulses of the signal Sh.

The output S _{18 of the} inverter 18 in which the output of the ripple carry terminal CY of the counter circuit 17 is inverted.
Goes low only when the count value of the counter circuit 17 reaches the maximum (SA, SB, SC, SD = "1") as shown in FIG. 6 (g).

Further, the output S18 is supplied to the clock terminal CK of the FF 20 and frequency-divided by 、. The output S20 of the non-inverted output terminal Q of the FF 20 becomes as shown in FIG. The output S20 * of Q * has an inverted waveform of S20. The output SD of the most significant bit of the counter circuit 17
Is supplied to the inverter 19 and the OR gates 21a and 21c, and the output S19 of the inverter 19 is supplied to the OR gate 21b,
21d.

The OR gate 21a outputs the outputs SD, S
OR gate 21b gates outputs S19 and S20, OR gate 21c gates outputs SD and S20 *, and OR gate 21d gates outputs S19 and S20 *. By these gate processes, OR gate 2
Outputs S21a to S21d of 1a to 21d are shown in FIG.
As shown in (l).

[0042] Then, each output S _21a to S _21d output SA~SC and OR gate 21a~21d of the counter circuit 17 formed on the basis of the horizontal synchronizing signal Sh corresponding to the output Se, Sf, Sg in Figure 1 A selection signal is formed, and the outputs SA to SC are supplied in parallel to the control terminals A to C of the analog switch circuits 22a to 22d, and the outputs S _21a to S _21
S21d is supplied to the inhibit gate terminal INH of each of the analog switch circuits 22a to 22d.

At this time, the outputs S21a to S21d always select one of the analog switch circuits 22a to 22d, and the outputs SA to SC output the selected analog switch circuits 22a to 22d by a combination of the three bits. Each of the input terminals X0 to X7 is alternatively selected and connected to the output terminal X.

With this connection, the output terminals X of the selected analog switch circuits 22a to 22d are connected to the variable resistors VR8 to VR15, VR1 of the selected input terminals X0 to X7.
6 to VR23, VR24 to VR31, VR32 to VR3
9 and the voltages Vxa to Vxa set by the resistors R7 to R11.
Either Vxd occurs alternatively.

Then, one or more selected analogs
Set voltages Vxa to Vxd of switch circuits 22a to 22d
Are combined via resistors R7 to R10, and the combined voltage is integrated by an integrating circuit of resistors R11 to R13 and a capacitor C8.
Integral smoothing is performed to form a correction amount adjustment voltage for each correction section.

The output Sx 'of the correction amount adjustment voltage corresponds to the output Sx of FIG. 1, and the output Sx' is used for scanning the CRT screen.
Accordingly, the correction voltage is supplied to a correction circuit unit similar to the correction circuit unit 5 in FIG. 1, and the correction amount adjustment voltage in each correction section is superimposed on the parabolic wave voltage. Note that the output Sx ′ becomes a broken-line waveform obtained by integrating a solid-line step-like waveform obtained by combining the voltages Vxa to Vxd, for example, as shown in FIG.

In this embodiment, the selection of the four analog switch circuits 22a to 22d and the eight variable resistors V of each of the analog switch circuits 22a to 22d are performed.
.., VR32 to VR39, each vertical scanning period is divided into a much larger number of correction sections than in the first embodiment. In addition, the output SX 'is smoothed and the discontinuity of the correction amount is eliminated.

As a result, the correction amount can be adjusted more finely than in the case of the first embodiment, and the accuracy of distortion correction is significantly improved. The configuration and the like of each unit are not limited to the two embodiments, and the correction amount adjustment units 9A and 9B may be formed by a memory circuit, for example.

[0049]

Since the present invention is configured as described above, it has the following effects. Correction interval setting unit 8A, its accordance CRT screen scanned by 8B
Each of a plurality of correction sections that divide the entire screen vertically
Les are selection signals of the correction amount adjusting voltage formed, these based on the selection signal rather correction amount adjuster 9A, and 9B each correction interval
By the selection of the set voltage, by superimposing the correction amount adjustment voltage suitable for each correction interval in Pas Laboratoires wave voltage V2 in accordance with the screen scan to adjust the amount of correction of the voltage V2, adjusted parabolic wave voltage horizontal output circuit by V2 2 horizontal deflection coils L2
Can be modulated. In this case, CR
The entire screen of T is divided into a plurality of vertically independent correction sections.
Arbitrarily set the parabolic wave voltage for each correction section.
The correction amount adjustment voltage can be superimposed on the CRT screen.
For the whole, according to the scanning, left
The right pincushion distortion can be corrected. Therefore, the pincushion distortion of the CRT screen including the vertically asymmetric distortion, which cannot be corrected conventionally, can be corrected with higher accuracy than in the past. It has a remarkable effect when applied.

[Brief description of the drawings]

FIG. 1 is a block connection diagram of one embodiment of a left and right pincushion distortion correction device of the present invention.

2 (a) to 2 (h) are timing charts for explaining the operation of each unit in FIG.

FIGS. 3A to 3F are timing charts showing an example of the adjustment characteristics of FIG.

FIG. 4 is a front view of a CRT screen for explaining a correction effect in FIG. 1;

FIG. 5 is a block connection diagram of another embodiment of the present invention.

6 (a) to 6 (m) are timing charts for explaining the operation of FIG.

[Explanation of symbols]

 2 Horizontal output circuit 8A, 8B Correction section setting unit 9A, 9B Correction amount adjustment unit L2 Horizontal deflection coil V1 Vertical sawtooth voltage V2 Parabolic wave voltage Sv Vertical synchronization signal Sh Horizontal synchronization signal

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-29172 (JP, A) JP-A 1-177661 (JP, U) JP-A 60-124165 (JP, U) JP-A 60-124 98969 (JP, U) JP-A 52-159113 (JP, U) JP-B 54-5249 (JP, B2) JP-B 56-8298 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 3/23

Claims (1)

(57) [Claims] 1. A right and left pincushion distortion which integrates a vertical sawtooth voltage to form a parabola wave voltage for correcting pincushion distortion, and modulates a current flowing through a horizontal deflection coil of a horizontal output circuit in a vertical cycle by the parabola wave voltage. in the correction device, a vertical synchronizing every vertical period of the signal based on a plurality of correction sections
At the timing of screen scanning in each of the correction sections.
Serial and correction interval setting unit for forming a selection signal for each correction interval each correction amount adjustment voltage, said alternatively selected voltage, or each set voltage by the selection signals from a plurality of set voltage by each selection No.択信From
A correction amount adjusting unit configured to superimpose an integrated smoothed voltage of a voltage obtained by combining a plurality of selected voltages in parallel via a resistor on the parabolic wave voltage as the correction amount adjustment voltage, wherein a right and left pincushion distortion correction is provided. apparatus.