JPS6163180A - Digital convergence device - Google Patents

Abstract

PURPOSE:To prevent a spreading of adjusting points on a screen and to adjust with good accuracy by installing a vertical direction adjusting point section processing part, LPF, etc., and displaying always the same number of adjusting points on a screen. CONSTITUTION:Plural convergence adjusting points are generated and displayed from a video circuit 7 of a color TV receiver in the horizontal and vertical directions of a screen, and position information of the adjusting points is inputted from a control panel 12 to which a synchronizing signal is inputted, and supplied to one frame memory 10. An adjusted quantity for the adjusting points is stored to the memory 10, and a horizontal scanning frequency is detected from a synchronizing signal at a horizontal scanning frequency detecting part 26. By the detecting signal, a reading address control part 5 is controlled and a convergence corrected quantity is read by the memory 10. At a vertical direction adjusting point section processing part 29, the number of scanning lines between scanning lines in the vertical direction is set, D/D-converted 14, LPF30, supplied to a deflecting coil 17, the same number of the adjusting points is always displayed on the screen and adjustment with good accuracy is executed.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for correcting the convergence of a color television receiver, which can be adjusted with high precision and is fully compatible with input synchronization signals having different frequencies. The present invention relates to a possible digital convergence device.

Conventional configuration and its problems Generally, color television receivers have red and green.

An image is created by combining the three colors of blue on a fluorescent surface or an attached screen, but in this case, accurately aligning the three colors, that is, convergence adjustment, is an important issue that affects image quality. Here, we will explain the convergence deviation using a color television receiver as an example.0 In Figure 1, 1 indicates a projection screen for comparing images, and 2, 3, and 4 are It is a projection type cathode ray tube equipped with an optical lens that forms an image obtained on the light surface onto the projection screen 1, and each fluorescent light surface has three colors of red, green, and blue.
A color image is obtained.

As shown in Figure 1, when these picture tubes are arranged horizontally, their projection angles with respect to the projection screen 1 are different, so the projected raster will be misaligned for each color as shown in Figure 2. .

In FIG. 2, a solid line 3j shows a raster projected by the picture tube 3 for green light, a broken line 41 shows a raster projected by the picture tube 4 for blue light, and a dash-dotted line 21 shows a raster projected by the picture tube 2 for red light.

To correct this positional shift, the projection type cathode ray tubes 2 and 3 must be
．． 4 is provided with a convergence adjustment coil separate from the main deflection yoke, amplitude modulates the sawtooth wave current in the horizontal scanning period in the vertical period, and adjusts the amplitude independently for each color.

However, this amount of color shift is due to variations in the position of the mounting of each picture tube, variations in the configuration of the optical lens system, etc.
Since the convergence varies depending on changes in the projection screen position, etc., it is impossible to perform highly accurate convergence adjustment with a combination of a simple sawtooth wave current or a parabolic current.

As a method for realizing such convergence adjustment, a convergence circuit having a digital correction waveform forming section has been considered.

The conventional digital convergence device will be explained in detail below with reference to FIG.

Horizontal and vertical periodic pulses synchronized with the deflection current period are applied as synchronization signals, thereby driving the read address control unit 6. The pulses from the read address control section 5 are used to drive the crosshatch pattern generator 6 to project the black and white pattern on the projection screen. Figure 2 shows the Nicross hatch pattern. On the other hand, use the address key on the control panel 12 to select the cross point at the position where convergence correction is required (for example, A in FIG. 4).
, and set the position address in the write address control unit 8. Next, using the data write key of the color to be corrected, for example, red provided on the control panel 12, write the correction amount into the one frame memory 1Q through the data reversible counter 11 while looking at the screen. Normally, this one-frame memory writing is controlled by switching by the multiplexer 9 so that it is performed during the blanking period of the video signal. Therefore, reading is not impaired.

Similar operations are performed at each adjustment point as described above. Next, the readout of the one frame memory 1o is performed by the readout address control unit 5 for the cross position of each crosshatch on the screen, and through the register 18 driven by the readout address control unit 5, the vertical interpolation process is performed. Regarding the operation of the zero-order correction processing in which the correction amount processing is performed in the vertical direction between the crosshatches in the section 13, the fourth
Figure 6 explains υ.

The amount of correction for each scanning line between points A and B or between points 0 and D shown in Figure 4 is (A-B)K+A or (C-D)K+C
You can ask for more. Here, K indicates a value obtained by linear approximation, and is written in the ROM in advance. Therefore, it is clear that K can be determined from the number N of scans between points A and B. The number N of scanning lines is determined from the number M of scanning lines in one field and the number of horizontal lines in the crosshatch. Then the fourth
The correction amount processing between points A and B in the figure will be explained with reference to FIG. The correction amounts of points A and B read from the one frame memory 1Q by the read address control unit 6 are stored in the register 1, IJ.
Registers 2 and 19 are registered.

The output signals of registers 1, 2.18.1-9 are subtracted by subtracter 22.
is multiplied by the coefficient for each scanning line from the coefficient generator 21 to obtain (A-B)K, and the adder 23 outputs p(A-
B) K+A is sent out. In this way, the correction amount for the scanning line for which the correction amount is not stored is determined. Next, the output signal is converted into an analog fish signal by the D/A converter 14 in FIG. Next, the correction amount in the horizontal direction is smoothed through a reduced pass filter (LPF) 1s, and is added to the output amplification section 16.
A correction current is supplied to the convergence coil 17. Convergence adjustment at each adjustment point is performed as described above.

However, in conventional digital condensation devices, when the synchronization signals of the horizontal and vertical synchronization pulses are different,
In each case, the number of scanning lines between the adjustment points of the vertical interpolation processing section 13 shown in FIG. 3, the value of the coefficient generator 21 shown in FIG. Unless the cutoff frequency of the LPF is changed, the distance between the cross points of the crosshatch pattern displayed on the entire screen changes, resulting in a problem in that convergence cannot be adjusted properly.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a digital convergence device that performs accurate convergence adjustment even when the frequencies of human synchronization signals are different.

Structure of the Invention The present invention provides a means for digitally storing a convergence correction amount for each adjustment point, a means for detecting a horizontal scanning frequency from a synchronizing signal input to a receiver, and a means for detecting a horizontal scanning frequency from a synchronization signal input to a receiver, and a method for storing a memory element using the detected signal. means for controlling the address and reading a convergence correction amount corresponding to the horizontal scanning frequency; means for setting the number of scanning lines between the vertical difference points A based on the detected signal; and means for setting the number of scanning lines between the adjustment points. a vertical adjustment point-to-point processing means that controls a coefficient setting means for the scanning line and calculates a convergence correction amount between the adjustment points from the difference between the correction amounts of the upper and lower adjustment points and the coefficient value; It is a digital convergence device equipped with a reduced pass filter means for controlling the off-frequency, and the address of the storage element, the number of scanning lines between adjustment points, the coefficient value for each scanning line, and the like according to the input horizontal scanning frequency. By controlling the cutoff frequency of the LPF, even when the input horizontal scanning frequency is different,
It is important to perform accurate convergence adjustment.

DESCRIPTION OF THE EMBODIMENTS FIG. 6 shows a block diagram of a digital convergence device according to the first embodiment of the present invention. In FIG. 6, parts that operate in the same way as in FIG. 3 are designated by the same numbers and their explanations are omitted. do.

In FIG. 6, 26 is a horizontal scanning frequency detection section, 27 is an adjustment point interval setting section, 28 is a coefficient setting section, 29 is a vertical adjustment point interval processing section, and 3Q is an LPF, which is based on the input synchronization signal. A horizontal scanning frequency detection section 26 that detects the horizontal scanning frequency, and an adjustment point interval number setting section 27 that sets the number of adjustment points in the vertical direction and its coefficient based on the detected signal, and a coefficient setting section. 28, a vertical adjustment point inter-point processing section 29 which calculates the convergence correction amount between the adjustment points from the difference between the correction amounts of the upper and lower adjustment points, the set number of adjustment points and the coefficient; It is for smoothing the correction amount, and is composed of an LPF 30 whose cutoff frequency can be controlled by the detected signal.

The operation of the digital convergence device of this embodiment configured as described above will be explained below. A horizontal synchronization signal synchronized with the deflection current cycle is applied to the horizontal scanning frequency detection section 26. The horizontal scanning frequency detection section 26 is composed of a counter, etc., detects the horizontal scanning frequency, and includes an adjustment point interval number setting section 27, a coefficient setting section 2B, an LPF 30 . It is supplied to the write address control section 8 and the read address control section 5. The write address control section 8 and the read address control section 5 include an OA set point number setting section 2 and a coefficient setting section 28 which create an address signal corresponding to the horizontal scanning frequency based on the signal from the horizontal scanning frequency detection section 26. is set by a signal from the horizontal scanning frequency detection section 26 from among several kinds of adjustment point interval number data and coefficient data written in advance. The number of adjustment points data from the adjustment point number setting section 27 and the coefficient data from the coefficient setting section 28 are supplied to a vertical adjustment point processing section 29 . The operation and configuration of this vertical direction adjustment point processing unit 29 is the same as that shown in FIG. g6 of the conventional example. From the numerical data and coefficient data, the correction amount for each scanning line between the A difference points is calculated. The correction amount corresponding to each horizontal scanning frequency is smoothed by an LPF 30, for example, an active filter, whose horizontal scanning frequency is controlled by a signal from the horizontal scanning frequency detection section 26, and then read out from the memory 1o for one frame. The explanation will be omitted because the operation is the same as the conventional one. Effects of the Invention The digital convergence device of the present invention has a means for digitally storing the convergence correction amount for each adjustment point, and a means for digitally storing the convergence correction amount for each adjustment point, and a horizontal means for detecting a scanning frequency; means for allocating an address of a storage element from the detected signal to read a convergence correction amount corresponding to the horizontal scanning frequency; and a vertical adjustment point according to the detected signal. A means for setting the number of scanning lines between the adjustment points and a coefficient setting means for each scanning line based on the number of scanning lines between the adjustment points are controlled, and the convergence correction amount between the adjustment points is calculated based on the difference between the correction amounts of the upper and lower adjustment points and the setting. vertical direction adjustment point processing means for calculating from the number of scanning lines and coefficient values between the adjusted adjustment points;
By providing a reduced pass filter means for controlling the cutoff frequency using the detected signal, the same number of adjustment points can always be displayed on the screen. Therefore, the distance between the adjustment points on the screen will not be widened, allowing for highly accurate adjustment. Furthermore, by having a large amount of ROM contents in the adjustment point number setting section and coefficient setting section, it is possible to deal with synchronization signals of all frequencies, which has a great practical effect.

[Brief explanation of the drawings] Figure 1 is a block diagram showing the principle of a projection type color television receiver, Figure 2 is a diagram to explain the convergence deviation, and Figure 3 is a block diagram of a conventional digital convergence device. 4 and 5 are diagrams for explaining the operation of the conventional device, and FIG. 6 is a block diagram of the digital convergence device in one embodiment of the present invention. 26...Horizontal scanning frequency detection section, 27...
...Adjustment point interval setting section, 28...Coefficient setting section,
29...Vertical direction adjustment point processing unit, 30...
・・・LPF, a・mountain...Write address control section, 6
...Read address control section, 10...
1 frame memory.

Claims (1)

[Claims] a display means for generating and displaying a plurality of convergence adjustment points in the horizontal and vertical directions on the screen of a color television receiver; an input means for inputting position information of the adjustment points; and a digital display means for inputting the convergence correction amount for the adjustment points. a detecting means for detecting a horizontal scanning frequency from a synchronizing signal input to the receiver; and a detecting means for controlling an address of a memory element based on the detected signal so as to correspond to the horizontal scanning frequency. reading means for reading out the convergence correction amount; setting means for setting the number of scanning lines between adjustment points in the vertical direction based on the detected signal; and coefficient setting means for each scanning line from the number of scanning lines between adjustment points in the vertical direction. vertical adjustment point processing means for controlling the convergence correction amount between the adjustment points and calculating the convergence correction amount between the adjustment points from the difference between the correction amounts of the upper and lower adjustment points and the coefficient value; and controlling the cutoff frequency using the detected signal. a digital convergence device comprising: reduced pass filter means;