JPS61133779A - Vertical line warp correction circuit - Google Patents

Abstract

PURPOSE:To display original vertical line image to the extent that the warp cannot deteced by human eye, by adjusting and feeding back the phase, etc. output signal of the frequency division circuit which divides the output pulse of the horizontal oscillation circuit to the output terminal of the horizontal oscillating circuit. CONSTITUTION:An attenuator 21 adjusts the level of the input pulse and sends it to a phase adjuster 22 where phase is adjusted. The output pulse of the phase adjuster 22 is added to the output pulse of horizontal oscillating circuit 4 by an adder 23. When the division ratio of a division circuit is 1/2, the output pulse of the horizontal oscillating circuit 4 deviates its phase by alpha for every 2H as shown in the diagram A, but as the pulse of cycle 2H as shown in the diagram B picked up by a phase adjusting circuit 22 is added to horizontal oscillating pulse as shown in the diagram B at the adding point 23, the pulse which has constant 1H phase as shown in the diagram C is supplied to the input terminal of a horizontal drive circuit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vertical line bending correction circuit, and in particular to a circuit that divides the output signal frequency of a horizontal oscillation circuit, such as a high-voltage output circuit or a switching power supply circuit, into an integer by a frequency dividing circuit. The present invention relates to a vertical line curvature correction circuit for correcting the curvature of vertical lines on a screen in a raster scan type display device having a circuit operated by a signal obtained by dividing the frequency of the vertical line.

Conventional technology Figure 4 shows a television receiver and monitor television.

1 shows a block system diagram of an example of a main part of a general raster scan type display device such as a computer display. In the figure, the horizontal synchronization pulse that enters the input terminal 1 is supplied to the horizontal AFC circuit 3 through the pulse shaping circuit 2, and here, in order to remove disturbances in horizontal synchronization due to noise,
A signal taken out at the average period of a predetermined number of periods of the input horizontal synchronizing pulse is supplied to the horizontal oscillation circuit 4, and its oscillation frequency is variably controlled. As a result, synchronized with the average period of the horizontal synchronization pulse taken out from the horizontal oscillation circuit 4,
The pulses at the horizontal scanning frequency r+ are amplified and waveform-shaped by the horizontal drive circuit 5 and then supplied to the horizontal output circuit 6 . A sawtooth wave tail flow having a horizontal scanning frequency fH is caused to flow through the horizontal flattened coil 7 by the horizontal output circuit 6. Further, the output signal of the horizontal output circuit 6 is divided into 1/n (
However, the frequency is divided into periods n-H (where n is an integer greater than or equal to 2).
However, after being converted to a pulse with H = horizontal scanning period),
High voltage or power supply drive circuit 9 and high voltage or power supply output circuit 1
0 and then supplied to the switching transformer 11.

Switching transformer 11 and next stage rectifier/smoothing circuit 12
This means that the frequency-divided pulse with a period of 0·H is boosted, then rectified and smoothed, and the resulting high voltage or DC power supply voltage is output to the output terminal 13.

Problems to be Solved by the Invention A raster system that drives circuits that operate with large energy, such as high-voltage output circuits and switching power supply circuits, with a signal having a frequency 1/n times the output signal frequency fH of the horizontal oscillation circuit 4. In a scan type display device, a high voltage or power output circuit 10. Or the noise component from the switching transformer 11,
Pulse shaping circuit 2. In order to interfere with the horizontal AFC circuit 3 or the horizontal oscillation circuit 4, the phase of the output pulses of the horizontal oscillation circuit 4 is shifted every n times, resulting in a phenomenon in which the scanning line on the screen shifts to the left or right every n grains. .

Therefore, for example, if the value of the integer n is "2", the output pulse of the horizontal oscillation circuit 4 will shift in phase by α every two days, as shown in FIG. As shown by 15 and 16 in FIG. 5, the lines result in an image shifted to the left or right for each scanning line.

In order to prevent this vertical line bending phenomenon, it is necessary to provide strict shielding to the required circuits, or insert a low-pass filter into the input side of the horizontal AFC circuit 3 or the low-voltage power supply line. However, even if these methods are adopted, it is difficult to correct the vertical line bending to such an extent that it cannot be visually detected.

Therefore, the present invention solves the above problem by adjusting the phase etc. of the output signal of a frequency dividing circuit that divides the output pulse of the horizontal oscillation circuit and feeding it back to the output terminal of the horizontal oscillation circuit. The purpose is to provide a correction circuit.

Means for Solving the Problems The vertical line bending correction circuit according to the present invention uses a frequency-divided signal of an integer fraction of the output signal frequency of a horizontal excavation circuit extracted from a frequency dividing circuit in a raster scan type display device. is supplied to an adjustment circuit, where at least the phase of the phase and level is adjusted. The output signal of this adjustment circuit is added and combined with the output signal of the horizontal oscillation circuit by a combining means to form a composite signal having a constant phase.

Effect When the frequency dividing ratio of the frequency dividing circuit is set to 110, the output signal (pulse) of the horizontal oscillation circuit 4 has a vertical line bending phenomenon because the phase deviates from 1H every n scanning lines as described above. However, by adding and synthesizing the output signal of the adjustment circuit and the output signal of the horizontal excavation circuit by the synthesis means, the above-mentioned phase shift for each n scanning line is corrected, and the frequency dividing circuit always has a constant value. A pulse with a phase of H period is supplied. Hereinafter, the circuit of the present invention will be explained in more detail along with examples.

Embodiment FIG. 1 shows a block diagram of an embodiment of a vertical line bending correction circuit according to the present invention. In the figure, the same components as those in FIG. 4 are denoted by the same reference numerals, and the explanation thereof will be omitted. In FIG. 1, the switching transformer 20 has a configuration in which, for example, a new winding is added to its negative side, and a pulse with a period of n-)1 is supplied from the newly added winding to the attenuator 21. do. The attenuator 21 adjusts the level of the input pulse and outputs it to the phase adjuster 22, where phase adjustment is performed. The level adjustment by the attenuator 21 and the phase adjustment by the phase adjuster 22 are performed by a person while monitoring the screen so that, for example, a vertical line is displayed on a monitor display device so that it visually looks like the original vertical line. It will be done.

The output pulses of the phase adjuster 22 are summed together with the output pulses of the horizontal excavation circuit 4 at a summing point 23. Now, if the frequency division ratio of the frequency dividing circuit 8 is set to 1/2, the output pulse of the horizontal oscillation circuit 4 will be <28 as shown in FIG. 2(A), as described above.
Although the phase is shifted by α every time, the pulse as shown in FIG. 2(B) with a period of 2H extracted from the phase adjustment circuit 22 is added to the horizontal oscillation pulse shown in FIG. 2(A) at the loading point 23. Since the signals are combined, the input terminal of the horizontal drive circuit 5 is supplied with a 1H cycle pulse whose phase is always constant, as shown in FIG.

As a result, on the screen, for example, two vertical lines are 25 in Figure 3.
．． As shown at 26, the vertical lines are displayed as original straight vertical lines with no visible bends.

It should be noted that the present invention is not limited to the above-described embodiments, and the branching means for frequency-divided pulses is not limited to changing the configuration of the switching transformer 20. For example, the output terminal of the high voltage or power output circuit 1o and the ground Two capacitors may be connected in series between the capacitors and the capacitor may be taken out from the midpoint between the two capacitors, and various other methods may be considered. In addition, by the attenuator 21 and the phase adjustment circuit 22,
Although the level and phase of the frequency-divided pulse are adjusted, it is possible in principle to correct vertical line bending by adjusting at least the phase.

Effects of the Invention As described above, according to the present invention, it is possible to always supply a 1H cycle pulse with a constant phase to the horizontal drive circuit, so that it is possible to produce an original vertical line image in which vertical line bending is hardly visually noticeable. It has features such as being able to display images.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the circuit of the present invention;
FIG. 2 is a signal waveform diagram for explaining the operation of the block system shown in FIG. FIG. 5 is a block diagram showing an example of a main part of a typical display device; FIG. 5 is an enlarged view showing a main part of a vertical line image on a screen by the device shown in FIG. DESCRIPTION OF SYMBOLS 1...Horizontal synchronization pulse input terminal, 2...Pulse shaping circuit, 3...Horizontal AFC circuit, 4...Horizontal oscillation circuit, 5...Horizontal drive circuit, 7...Horizontal deflection coil, 8... Frequency dividing circuit, 11.20... Switching transformer, 15.16, 25.26... Vertical line, 21...
・Attenuator, 22... Phase adjustment circuit, 23...
Additional points.

Claims (1)

[Claims] In a raster scan type display device having a circuit that operates using a signal obtained by dividing the output signal frequency of a horizontal oscillation circuit into an integer by a frequency dividing circuit, the phase and level of the output signal of the frequency dividing circuit may be changed. A vertical line comprising at least an adjustment circuit that adjusts the phase, and a synthesizing means that adds and synthesizes the output signal of the adjustment circuit with the output signal of the horizontal oscillation circuit to output a composite signal having a constant phase. Bending correction circuit.