JPS58201486A - Digital convergence device - Google Patents

Abstract

PURPOSE:To attain the convergence adjustment especially for the circumference easily with good accuracy, by adding a simple circuit. CONSTITUTION:In adjusting the adjusting points at the outside of a screen independently, the points are changed by observing an auxiliary pattern, allowing to improve the accuracy of the convergence of the circumference. An adjusting point pattern generating circuit 18 generates a pattern and an auxiliary pattern generating circuit 19 generates a pattern corresponding to the intermediate pattern of the adjusting point pattern. The adjusting point pattern and the auxiliary pattern are summed at diodes D1, D2, and a signal level of the auxiliary pattern is reduced at a resistor R1. The pattern and a cursor signal are summed at resistors R2, R3 and the result is applied to a video circuit from an emitter of a transistor Q1 as a convergence adjusting signal. Further, an output signal level is set with emitter resistors R4 and R5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a convergence circuit for a color television receiver, and an object of the present invention is to provide a digital convergence device that can be adjusted quickly and accurately.

In the color picture tube of the Nyadou mask method used in general color television receivers, the radius of curvature of the shadow mask is larger than the separation from the center of the shadow mask to the center of the shadow mask, resulting in color shift. However, in projection-type color receivers that use three picture tubes emitting the three primary colors to project enlarged images onto a screen, the angle of incidence of the picture tubes on the screen is different for each picture tube, so the colors on the screen are different. Misalignment occurs. The superposition of these three primary colors, so-called convergence, is performed by creating a correction waveform synchronized with the horizontal and vertical scanning cycles and adjusting this waveform. This method tends to have large convergence defects around the image, and requires skill to adjust. For this reason, a method of digitally creating a convergence correction waveform has been proposed as a method of performing convergence with higher precision over the entire screen.

This digital convergence method projects a convergence correction pattern such as a dot signal on the screen, digitally writes convergence correction data for each point in one frame memory, and then scans this data horizontally and vertically. It is read out in synchronization with the signal and performs 1)/A conversion to create a convergence correction waveform.

This will be explained in detail below with reference to FIGS. 1 and 2. First, as shown in FIG. 1, when dots corresponding to the convergence adjustment points are displayed on the screen, for example in 9 rows in the vertical direction and in 9 columns in the horizontal direction, or when a synchronization signal is applied from the crosshatch synchronization input terminal 15, the control circuit 7 and the correction The image is displayed on the cathode ray tube screen by the pattern generation circuit 13. Next, select the dot corresponding to the adjustment point you wish to adjust using the cursor keys on the control panel 1. The address of the adjustment point selected with the cursor key is stored in the cursor counter 8. The address stored in the cursor counter 8 is applied to the coincidence detection circuit 1o together with the address of the 1-frame memory control counter 11 which sequentially outputs the address of each adjustment point of the dot pattern, and is combined with the output signal of the 1-frame memory control counter 11. ,
When the output signals of the cursor counter 8 match, a match detection circuit 10 generates a match output signal. The match output signal is then applied to the cursor generation circuit 12. The cursor generation circuit 12 generates a cursor signal corresponding to the storage address of the cursor counter 8. Next, the output signal of the cursor generation circuit 12 is added to the dot pattern signal of the correction pattern generation circuit 13 by the addition circuit 14, and the cursor is displayed on the television screen by superimposing it on the selected adjustment point.

After selecting the adjustment point as described above, the desired correction amount is set on the reversible counter 2 while looking at the screen using the writing key for the color 2 to be corrected, for example, red provided on the control panel 1. Next, the output signal of the reversible counter 2 is written to the address designated by the cursor counter 8 of the one frame memory 3 via the data multiplexer 17. When writing the correction amount to the 1-frame memory 3, the output of the reversible counter 2 is written. In addition to Mujin Mori 3, the contents of that address are being read. If you want to further increase the convergence correction amount,
When you want to increase or decrease the count number of the reversible counter 2, decrease the count number of the reversible counter 2 and transfer the address specified by the cursor counter 8 to the 1 frame memory 3 via the address multiplexer. In addition to 3, write to the address.

Next, reading from the one frame memory 3 will be explained.

Reading of the 1 frame memory 4 is performed using the first frame memory 4 according to the address signal output from the 1 frame memory control counter
It is read out in synchronization with the dot pattern shown in the figure. However, since the one-frame memory 3 only has correction amount data for locations corresponding to virtual adjustment points, it is necessary to find the correction amount for each scanning line between the adjustment points in the vertical direction. Therefore, interpolation calculation circuit 4
For example, in the case between points A and B in FIG. 1, the amount of correction for each scanning line included between points A and B is determined from the amount of correction at point A by interpolation. Next, the operation of the interpolation calculation circuit 4 will be explained. For example, in the vertical direction between points A and B shown in FIG.
Assuming that the correction amount for point a, the correction amount for point B, and the number of scanning lines between point A and B are Xn, and the coefficient Kn corresponding to each scanning line, then the correction amount for each scanning line is (a-b) It can be determined by Kn+a. Here, linear interpolation or non-linear interpolation is determined by the coefficient KnO value.

Next, the extrapolation calculation circuit 16 for calculating the amount of correction outside the screen will be explained. For example, when calculating the correction amount for point C in FIG. 1, this extrapolation calculation circuit 16 uses C-(
A linear interpolation calculation of D-E)+D is performed, and this correction amount is written to the address of point C in one frame memory B(7) via the data multiplexer 17. Therefore, the amount of correction for the 0 point is within the screen.

This changes by changing the amount of correction at point E. In the above manner, the convergence correction amount for each adjustment point is determined.

Next, the output signal of the interpolation calculation circuit 4 is converted into an analog signal by the D/A conversion circuit 5. Since the output signal of the D/A conversion circuit 6 has a staircase waveform, it is passed through a low pass filter (LPF) e.
After smoothing and widening, the signal is supplied to a convergence coil (not shown) to correct red, green, and blue.

Such a digital convergence device can perform convergence correction at each adjustment point independently, so that convergence correction can be performed with high accuracy.

However, as mentioned above, since it is obtained by extrapolation of correction outside the screen, due to variations in the magnetic field around the deflection yoke, etc., as shown in Figure 1, the result of combining the color shift at point E,
The outer part of the screen will be slightly misaligned, making it impossible to perform highly accurate convergence adjustment. Therefore, high-quality images cannot be displayed on high-definition character displays.

Therefore, instead of finding the correction amount for off-screen adjustment points only by extrapolation calculation, a method that can change the correction amount independently is considered.
Using this method improves the peripheral convergence accuracy. However, as shown in FIG. 1, with the conventional adjustment pattern, the off-screen adjustment points are not visible, so the necessary correction amount is unclear.

The present invention eliminates the above-mentioned drawbacks and allows peripheral convergence adjustment to be performed easily and accurately.
Examples of the present invention will be described below.

Figure 3 A2 shows a diagram in which the auxiliary pattern is superimposed on the adjustment point pattern and projected on the screen. As is clear from the figure, when adjusting the adjustment points outside the screen independently, the peripheral convergence accuracy can be improved by changing the auxiliary pattern while looking at it.

FIG. 4 is an embodiment of a circuit that generates the pattern of FIG. In FIG. 4, the adjustment point pattern generation circuit 18
The circuit that generates the conventional pattern shown in Figure 1, the auxiliary/
A pattern generating circuit 19 generates a pattern corresponding to the middle of the adjustment point pattern shown in FIG. 3, and 20 is a conventional cursor generating circuit. The adjustment point pattern and the auxiliary pattern are added by diodes D1 and D2, and the signal level of the auxiliary pattern is reduced by the resistor R1.

The pattern and cursor signals are added by resistors R2 and R3, and are supplied to the video circuit as a convergence adjustment signal from the emitter of transistor Q1. Further, the output signal level is set by emitter resistors R4 and R6.

In order to distinguish between the auxiliary pattern diagram and the pattern diagram showing the convergence adjustment points, the former may be displayed as a crosshatch signal and the latter as a dot signal, or the opposite signal may be displayed. According to the present invention, by adding a simple circuit, convergence adjustment, especially peripheral convergence adjustment, can be easily and accurately performed.

Incidentally, when the auxiliary pattern is not required, a switch can be provided in the auxiliary pattern generation circuit to make it erasable.

[Brief explanation of drawings]

Figure 1 is a pattern diagram when a correction pattern signal indicating the adjustment points of a conventional digital convergence device is displayed on a television receiver. Figure 4 is a pattern diagram when the adjustment pattern signal of the device is displayed on a television receiver.
FIG. 2 is a circuit diagram of a circuit for generating a pattern diagram of a digital convergence device in an embodiment of the present invention. 18...Adjustment pattern generation circuit, 19...
...Auxiliary pattern generation circuit, 2olIII society...cursor generation circuit) D D @a11@@ Diode, R1, R2, R31 2... Resistor, q... Transistor. Name of agent: Patent attorney Toshio Eko and 1 other person
1 shi4 Figure 3 Figure 4

Claims (1)

[Claims] (1) Means for generating a pattern that enables convergence adjustment at multiple points in the horizontal and vertical directions on the screen of a color television receiver, means for inputting positional information of the convergence adjustment points, and means for inputting position information of the foreboard adjustment points. 1. A digital convergence device comprising means for correcting convergence deviation and displaying an adjustment pattern diagram by superimposing an auxiliary crosshatch or dot signal on the crosshatch or dot signal indicating the convergence adjustment point. (≧ The auxiliary crosshatch or dot signal is displayed by line d to distinguish it from the crosshatch or dot signal indicating the convergence adjustment point) or the signal level is reduced and projected. Digital convergence device. (Cloudy) To distinguish between the auxiliary pattern diagram and pattern 1ヾ1 indicating the convergence adjustment point, the former should be displayed as a crosshatch signal and the latter as a dot signal, or the opposite signal should be displayed. A digital convergence device according to claim 1, characterized in that: