JPS6359191A - Digital convergence device - Google Patents

Abstract

PURPOSE:To attain convergence adjustment excellent in accuracy by controlling the address of a memory element and the cut off frequency of an LPF according to an inputted horizontal scanning frequency, selecting the memory element according to an aspect and controlling the number of scanning lines between search points and a coefficient value according to the number of scanning lines. CONSTITUTION:According to a signal from a horizontal scanning frequency detecting part 26 for detecting the horizontal scanning frequency of a signal, the address of one frame memory 10 and the cut off frequency of the LPF30 are controlled. According to a signal from an aspect detecting part 32 for detecting the aspect ratio, the one frame memory having various types of memories is selected, according to a signal from a scanning line number detecting part 31 for detecting the number of the scanning lines of the signal, the data of a setting part 27 of the number between the search points and a coefficient setting part 28 is controlled to perform a processing between vertical adjustment points. Thereby, since a space adjustment point position and the quantity of correction constantly correspond to the signal different in the input scanning frequency and the aspect ratio, the convergence can be adjusted with excellent accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for correcting the convergence of a color television receiver f3m, which can be adjusted with high accuracy and can be used even when the input synchronization signal has a different frequency and aspect ratio. The present invention relates to a fully compatible digital convergence device.

Conventional technology 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, accurate alignment of the three colors, that is, convergence adjustment, is an important factor that affects image quality. It becomes a challenge.

Here, we will use a projection type color television receiver as an example.
The convergence shift will be explained below.

In FIG. 2, 1 is a projection screen for projecting an image, and 2, 3, and 4 are projection-type cathode ray tubes equipped with optical lenses that form the image obtained on the fluorescent surface onto the projection screen 1. There are 3 red, green, and blue lights on each fluorescent surface.
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 is
A positional shift occurs as shown in the figure.

In FIG. 3, a solid line 31 shows a raster projected by the picture tube 3 for green light, a broken line 4e shows a raster N projected by the picture tube 4 for blue light, and a dashed-dotted line 21 shows a raster projected by the picture tube 2 for red light.

To correct this positional deviation, the projection type cathode ray tubes 2 and 3 must be
．． 4, a convergence adjustment coil is provided separately from the main deflection yoke, and the width of the sawtooth wave current in the horizontal scanning period is modulated in the vertical period, so that the amplitude can be adjusted independently for each color.

However, this amount of color shift is due to variations in the mounting position 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 labola 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 converter will be explained in detail below with reference to FIG.

Horizontal and vertical period signals synchronized with the deflection current period are input as synchronization signals, which drive the read address control section 5.
The cross-hatch pattern generator 6 is driven using the . Specify the cross point at the position that requires correction (for example, A in FIG. 5) and set the position address in the write address control section 8. Next, select the color you want to correct, for example, the red data provided on the control panel 12. Using the write key, while looking at the screen, write data through the reversible counter 11.
The correction amount is written in the 1-frame memory 1o. Usually this 1
The multiplexer 9 performs switching control so that writing to the frame memory is performed during the blanking period of the video signal. Therefore, reading is not required.

Similar operations are performed at each adjustment point as described above. Next, the one-frame memory 1o is read out by the readout address control section 5 for each Kuromeno Tsuchi cross position on the screen, and the vertical direction insertion is performed via the register 18 driven by the readout address control section 6. The inter-processing section 13 performs correction amount processing in the vertical direction between crosshatches.

Next, the operation of this correction process will be explained with reference to FIGS.

The amount of correction for each scanning line between points A, 4 and B or between point 0 and B shown in FIG. 6 is (A-B)K-! -A or (C-D)
It can be obtained from K10. Here, K indicates a value obtained by linear approximation, and is written in the ROM in advance. Therefore, it is obvious that K can be determined from the number N of scanning lines 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. Next, the correction amount processing between points A and B in FIG. 6 will be explained with reference to FIG. 1 frame memory 1 by read address control unit 5
The correction amounts of points A and B read from ゜ are stored in register 1.
18, registered in registers 2 and 19.

゛ The output signal of register 1.2.18.19 is subtracter 2
2, multiplied by the coefficient for each scanning line from the coefficient generator 21 to obtain (A-B)K, and the adder 23 calculates (A-
B) K+A is sent out. In this way, the amount of correction for the scanning line for which the amount of correction is not stored is determined. Next, the output signal is converted into an analog quantity by the D/A converter 14 in FIG. Next, the correction amount in the horizontal direction is smoothed through a low-pass filter (LPF) 1s, and is applied to the output amplification section 16 to supply a correction current to the convergence coil 17. Convergence adjustment at each adjustment point is performed as described above.

Problems to be Solved by the Invention However, in the conventional digital convergence device, when the synchronization signals of the horizontal and vertical synchronization pulses are different, the number of scanning lines between the adjustment points of the vertical direction interpolation processing section 13 shown in FIG. and L for smoothing the values of the coefficient generator 21 shown in FIG. 6, various address signals, and horizontal correction amounts.
If the PFO cutoff frequency is not changed, the distance between the cross points of the crosshatch pattern displayed on the entire screen will change, resulting in a problem that accurate convergence adjustment cannot be performed.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide a digital convergence device that performs accurate convergence adjustment even when input synchronization signals have different frequencies and aspect ratios.

Means for Solving the Interval Point The present invention comprises n storage means for digitally storing the convergence correction amount for each adjustment point, and a method for calculating the horizontal scanning frequency and the scanning line number aspect from the synchronization signal input to the receiver. means for detecting the ratio, means for controlling the address of a storage element using the signal detected by the horizontal scanning frequency, and reading a convergence correction amount corresponding to the horizontal scanning frequency; a control means for selecting a memory element; a means for setting the number of scanning lines between adjustment points in the vertical direction based on the signal detected for the number of scanning lines;
Vertical direction adjustment that controls a coefficient setting means for each number of scanning lines from the number of scanning lines between the adjustment points and calculates the convergence correction amount between the adjustment points from the difference in the positive amount of the upper and lower adjustment points and the coefficient value. The present invention is a digital convergence device comprising point-to-point processing means and low-pass filter means for controlling the cutoff frequency of a low-pass filter for smoothing the correction amount in the horizontal direction using the frequency detected signal.

According to the above-described configuration, the present invention controls the address of the storage element and the cutoff frequency of the LPF according to the input horizontal scanning frequency, selects the storage element according to the aspect, and selects the storage element according to the number of scanning lines. The number of scanning lines between adjustment points,
By controlling the coefficient values, accurate convergence adjustment can be performed even for different input scanning frequencies and aspect ratios.

Embodiment FIG. 1 shows a block diagram of a digital convergence device in a first embodiment of the present invention.

Components in FIG. 1 that operate in the same way as in FIG. 4 are designated by the same numbers and their explanations will be omitted. In FIG. 1, 26 is a horizontal scanning frequency detection section that detects a horizontal scanning frequency from an input synchronization signal, 31 is a scanning line number detection section that detects the number of scanning lines from an input synchronization signal, and 32 is a detection section that detects an aspect ratio from an input signal. The aspect detection unit 1o has n storage elements.
Frame memory, 26. 28 is an adjustment point number setting section and coefficient setting section for setting the number of adjustment points and coefficients in the vertical direction, 29
3o is a vertical adjustment point processing unit that calculates the convergence correction amount between adjustment points by calculating the difference between the correction amounts of upper and lower adjustment points, and the set number of adjustment points and coefficients; 3o is a cutoff frequency controlled The address of the one frame memory 1o is controlled by the horizontal scanning frequency detection signal, and the convergence correction amount corresponding to the horizontal scanning frequency is read out. In addition, the aspect detection signal selects one frame memory 1o, and the scanning line number detection signal performs vertical adjustment point-to-point processing, and then the horizontal correction amount is determined by the LPF 30 according to each horizontal scanning frequency. By doing this, the convergence correction amount corresponding to the input scanning frequency is read out from the one-frame memory 10.

The operation of the digital convergence device of this embodiment configured as described above will be explained below.

A horizontal synchronization signal HP synchronized with the deflection current cycle is applied to the horizontal scanning frequency detection section 26. Horizontal scanning frequency detection section 2
6 consists of a counter, etc., which detects the horizontal scanning frequency and
PF30. Write address control unit 8. It is supplied to the read address control section 5. The write address control section 8 and the read address control section 6 create an address signal corresponding to the horizontal scanning frequency based on the signal from the horizontal scanning frequency detection section 26. Further, a horizontal synchronization signal HP and a vertical synchronization signal vp synchronized with the deflection current cycle are applied to the scanning line number detection section 31. Similar to the horizontal scanning frequency detection section 26, the scanning line number detection section 31 is composed of a color filter or the like, and detects the number of scanning lines and controls the number of adjustment points setting section 27. It is supplied to the coefficient setting section 28. An input signal from the receiver is applied to an aspect detection section to detect the aspect ratio. The one frame memory 1o has several types of memories and is selected by a signal from the aspect detection section 31. The adjustment point interval number setting section 27 and the coefficient setting section 28 are set by a signal from the scanning line number detection section 31 from among several types of adjustment point interval number data and coefficient data written in advance.

The adjustment point interval number data from the adjustment point interval number setting section 26 and the coefficient data from the coefficient setting section 28 are supplied to the vertical direction adjustment point interval processing section 29 . The operation and configuration of this vertical direction adjustment point processing section 29 are the same as those in the conventional one shown in FIG.
A correction amount for each scanning line between adjustment points is calculated from the set data on the number of adjustment points and coefficient data.

The correction amount corresponding to each horizontal scanning frequency is smoothed by an LPF 30, such as an active filter, whose cutoff frequency can be controlled by a signal from the horizontal scanning frequency detection section 26. Next, reading and writing from the one-frame memory 10 are the same operations as in the prior art, so explanations thereof will be omitted.

As explained above, according to this embodiment, the address of the one frame memory 1o and the cutoff frequency of the LPF 30 are controlled by the signal from the horizontal scanning frequency detection section 26 that detects the horizontal scanning frequency of the signal, and the aspect ratio is also detected. Based on the signal from the aspect detection section 32, which selects one frame memory from several types of memories, the number of adjustment points setting section 27. By controlling the data of the coefficient setting section 28 and performing processing between vertical adjustment points,
Even if the input scanning frequency and aspect ratio are different, the spatial adjustment point positions and correction amounts always correspond to each other, so convergence adjustment can be performed with high precision. Also, the number of adjustment points setting section 27. By having a large ROM content in the coefficient setting section 28 and a large memory capacity of one flail memory, it is possible to handle any scanning frequency.

In the first embodiment, the aspect detection section 32 detects from the input signal of the receiver, but when the aspect ratio changes depending on the horizontal scanning frequency of different signals, the horizontal scanning frequency detection section 26 detects the aspect ratio from the input signal of the receiver. When the aspect ratio changes depending on the number of scanning lines, the aspect detection section 32 may be used as the scanning line number detection section 31.

As described in detail, according to the present invention, even for signal specifications with different input scanning frequencies, the adjustment point and correction amount always correspond to the same position on the screen, so convergence adjustment can be performed with high precision. , its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a digital convergence device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the principle of a projection type color television receiver, and FIG. 3 is a diagram for explaining the convergence deviation. Figure 4 is a block diagram of a conventional digital convergence device;
The figure is a diagram for explaining the operation of a conventional digital convergence device. 26...Horizontal scanning frequency detection section, 31...
... Scanning line number detection section, 27 ... Adjustment point interval setting section, 28 ... Coefficient setting section, 29 ... Vertical direction adjustment processing section, 3o. ...LPF, 8.
. . . Write address control section, 5 . . . Read address control section, 10 . . . 1 frame memory. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

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 horizontal scanning frequency detection means for detecting a horizontal scanning frequency from a synchronizing signal input to the receiver; a number of scanning lines to be detected, an aspect detection means to detect an aspect ratio from a signal input to the receiver, and an address of a storage element controlled by the signal detected by the horizontal scanning frequency, and a number of scanning lines corresponding to the horizontal scanning frequency. reading means for reading out a convergence correction amount; control means for selecting n storage elements based on a signal from the aspect detection means; and setting the number of scanning lines between adjustment points in the vertical direction based on the signal detected by the number of scanning lines. The setting means and the coefficient setting means for each scanning line of the number of scanning lines between the adjustment contacts in the vertical direction are controlled, and the convergence correction amount between the adjustment points is determined from the difference between the correction amounts of the upper and lower adjustment points and the coefficient value. A digital convergence device comprising vertical adjustment point-to-point processing means for calculating, and low-pass filter means for controlling a cutoff frequency of a low-pass filter for smoothing the horizontal correction amount using the frequency detected signal. Device.