JPS62193476A - Digital convergence device - Google Patents

Abstract

PURPOSE:To make unnecessar a complicated interpolation arithmetic circuit, and to adjust a convergence dislocation rapidly and with accuracy, by performing the approximate calculation of a correction data corresponding to a scanning line between adjusting points in a vertical direction, and providing a 1 frame memory which storage the correction data at the adjusting point, and between the adjusting points in the vertical direction. CONSTITUTION:Since only the correction data of a position corresponding to the adjusting point is written in a 1 frame memory (RAM) 4, it is necessary to write the correction data at every M-number of scanning lines included between the adjusting points in the vertical direction by finding it with the approximate calculation. Then, for example, a change share by every scanning line between the adjusting points is found from a correction quantity (a) on the first line, and a correction quantity (b) on the second line, and the correction quantity by every scanning line is found by adding the change share with the correction quantity on the second line. Next, the output signals of the 1 frame memory (RAM)4 are converted to analog quantities with D/A converters 5-8 for each color, and are smoothed at low-pass filters (L.P.F) 9-12, and after being amplified at amplifiers 13-16, they are supplied to convergence yokes for each color.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital convergence device that can quickly and accurately adjust convergence correction in a color television receiver.

BACKGROUND OF THE INVENTION As is well known, a shadow mask type color cathode ray tube (hereinafter abbreviated as CRT) used in general color television receivers has three electron guns, one for red, one for green, and one for blue.

However, it is structurally impossible to arrange all of these electron guns on the central axis of the iCRT, so they are installed slightly away from the central axis and slightly tilted inward with respect to the central axis. Therefore, on the screen on this central axis, each electron beam converges at the shadow mask, and simultaneously passes through the same hole and emits red, green, and blue fluorescent lights, creating a convergence state. . However, since the radius of curvature of the shadow mask is larger than the distance from the center of deflection to the center of the shadow mask, the three electron beams converge in front of the shadow mask at locations other than the central axis of the CRT. Therefore, the three electron beams cannot pass through the same hole at the same time, and the reproduced image has a color shift, that is, a convergence shift, which increases as it moves away from the center of the screen. In order to prevent such problems, it is necessary to perform convergence correction so that the three electron beams converge at the shadow mask over the entire screen.

However, in a projection color receiver that uses three CRTis that emit three primary colors to project an enlarged image onto a screen, CR
Since the angle of incidence of T on the screen is different for each CRT, color shift occurs on the screen.

The superposition of these three primary colors, so-called convergence, is generally done by using passive elements such as L, C, and R to obtain a convergence correction waveform in an analog manner from a horizontal flyback pulse and a vertical deflection waveform. has been adopted, but there is a problem in terms of convergence accuracy. On the other hand, a method of digitally performing convergence correction has been proposed as a method for achieving more accurate convergence.
ing.

The concept is to project a convergence correction pattern such as a crosshatch or dot on the screen, digitally write the convergence correction amount data for each point in one frame memory, and synchronize this information with horizontal and vertical scanning. The data is read out, D/A converted, amplified, and convergence correction is performed. The explanation will be given below based on FIGS. 2 and 3.

As shown in FIG. 2, there are, for example, nine rows in the horizontal direction on the screen.

Seven vertical lines of adjustment points? A crosshatch signal 28 shown is outputted from the hatch generator 27 and displayed on the screen.

The intersection of the crosshatches 29 on this screen becomes the adjustment point.

When an adjustment point is selected using the cursor key 21 of the control panel 1, the CPU 2 obtains the cursor address of the adjustment point and sets the cursor 3o in the register to be displayed. At this time, the address of the 1 frame memory 3 is also obtained.

Next, select the color you want to correct, for example red, using the z1 selection key 22 and press the data write key 23 to select the color on the screen. While checking, all the red color deviations are adjusted and the desired data is written to the specified address of the one frame memory 3. Then, in order, green\, blue↓.

Do the same for blue←. The same procedure is repeated for all adjustment points on the screen.

Next, reading out the convergence correction amount written in the one-frame memory 3 will be explained.

Since the one-frame memory 3 only has correction data for positions corresponding to the adjustment points shown in FIG. 2, it is necessary to perform interpolation for each scanning line between adjustment points in the vertical direction. Therefore, for example, by using the correction data of the first and second rows read from the one-frame memory 3, the amount of correction in the scanning line included between the adjustment points of the first and second rows is calculated. Interpolation calculation circuit 3
Determine by 1. Next, the output signal of the interpolation calculation circuit 31 is converted into an analog quantity by D/A converters 5, 6, 7.8 for each color, smoothed by low pass filters (LPF) 9, 1o, 11°12, After being amplified by amplifiers 13, 14, 15, and 16, it is supplied to the convergence yoke of each color.

In the digital convergence device described above, the adjustment points can be independently corrected as desired, so the accuracy is greatly affected by the convergence correction.

Next, the operation of the interpolation calculation circuit 31 will be explained in detail with reference to FIG. In FIG. 2, if M scanning lines are included between the adjustment points in the vertical direction, the correction amount of the n adjustment points written in one frame memory 3 is calculated from the M scanning lines between the adjustment points with no data. It is necessary to generate correction data corresponding to the line.

Therefore, for example, after reading all the correction amounts for the adjustment points in the first row from the one-frame memory 3 and setting them in the 1H register 32, reading out the correction amounts for the adjustment points in the second row from the one-frame memory 3, and setting the correction amounts for the adjustment points in the first row. The difference between the eye correction amount and the second row correction amount is calculated by the subtraction circuit 33 and multiplied by the weighting coefficient for each scanning line written in advance in the coefficient ROM 35 by the multiplication circuit 34.
The amount of change for each scanning line is obtained by multiplying by , and the addition circuit 36 adds this amount of change to the correction amount for the second row to perform full interpolation. Next, the output signal i of the adder circuit 3e D/A converter 5
, 6, 7.8 to convert it into an analog quantity.

In addition, as shown in FIG. 3, in order to save the interpolation calculation circuit 31, the interpolation calculations of four types of correction data: red/, green - 2 blue ↓, and blue ← are carried out by one interpolation calculation circuit 31. , which is done on a time-sharing basis.

Problems to be Solved by the Invention However, the interpolation calculation circuit 31 having the above configuration has the following problems:
In order to perform real-time processing, a complicated circuit must be constructed using all of the high-speed multiplication circuits 34 as shown in FIG. 4, which is a problem.

In view of the above problems, the present invention provides a digital convergence system in which all correction data corresponding to scanning lines between adjustment points in the vertical direction is generated and converted into analog quantities by a D/A converter without providing the interpolation circuit. It provides equipment.

Means for Solving the Problems In order to solve the above problems, the digital convergence device of the present invention has a non-volatile one-frame memory that stores all adjustment point correction data, as well as a memory for scanning between adjustment points in the vertical direction. It has one frame memory for storing correction data corresponding to a line, and stores correction data corresponding to all scanning lines obtained by approximate calculation from the correction data of each adjustment point in the one frame memory. .

Effect: The present invention can accurately adjust convergence over the entire screen using the above-described simple circuit configuration.

Embodiment Hereinafter, a digital convergence device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a digital convergence device in an embodiment of the present invention.

In FIG. 1, 4 is a one-frame memory of a random access memory (RAM) that stores all correction data corresponding to vertical adjustment points and scanning lines between them, and the other parts are the same as in FIG. Yes, explanation will be omitted.

The operation of the digital convergence device configured as described above will be explained using FIG. 1.

As shown in FIG. 2, a convergence correction crosshatch signal 28 indicating adjustment points in, for example, 9 columns in the horizontal direction and 7 rows in the vertical direction is output from the hatch generator 27 and displayed on the screen. The intersection of the crosshatches 29 on this screen becomes an adjustment point, and correction data for this point is stored in the nonvolatile memory 3 for one frame.

When an adjustment point is moved using the cursor keys 21 of the control panel 1, the CPU 2 obtains the cursor address of the adjustment point and sets the cursor in a register to be displayed.

At this time, the addresses of one frame memory (nonvolatile) 3 and one frame memory (RAM) 4 are also obtained. Next, select the color for which you want to correct the convergence shift, for example, using the red z2 selection key 22, adjust all red color shifts using the data write key 23 while looking at the screen, and store the desired data in one frame memory (
(Non-volatile) 3 and one frame memory (RAM) 4 at the specified address. Then, one after another, green.
Do the same for Blue ↓ and Iku →, and do the same for all the adjustment points on the screen below by moving the cursor 3o.

Next, reading of the convergence correction amount written in the one-frame memory (RAM) 4 at n will be explained.

In the 1-frame memory (RAM) 4, the above operation writes only the correction data for the positions corresponding to the adjustment points shown in Figure 2, so the correction for each M scanning line included between the adjustment points in the vertical direction is corrected. Data must be obtained by approximate calculation and written.

Therefore, as shown in Figure 2, for example, the correction amount for the first line and the correction amount for the second line are calculated as the change for each scanning line between the adjustment points, and this change and the correction for the second line are calculated. amount? In addition, the amount of correction for each scanning line is determined.

That is, the Nth (86M) correction amount C from the first row is approximated by the following equation.

1 frame memo IJ (RAM) 4 during vertical retrace period
write to.

Next, the output signal of the one frame memory (RAM) 4 is converted into an analog quantity by D/A converters 5, 6, 7.8 for each color, and low-pass filters (L, P, F) 9, 10 ,1
After smoothing with 1.12 and amplified with amplifiers 13, 14 and 15.16, it is supplied to the convergence yoke of each color.

As described above, this configuration can eliminate the conventional complicated interpolation calculation circuit 31 by providing the 1-frame memory (RAM) 4, and can also adjust fL without convergence quickly and precisely as in the conventional case. can.

Effects of the Invention As described above, according to the present invention, approximate calculation is performed using correction data 1cPU etc. corresponding to the scanning line between adjustment points in the vertical direction,
By providing one frame memory for storing correction data corresponding to vertical adjustment points and scanning lines therebetween, the conventional complicated interpolation calculation circuit can be eliminated. Then, using the same method as before, the convergence shift t can be quickly and accurately determined.
Can be adjusted.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of a digital convergence device according to an embodiment of the present invention, Fig. 2 is a front view showing the projected state of the cross note which is the convergence correction circuit, and Fig. 3 4 is a block diagram showing the configuration of a conventional digital convergence device, and FIG.
FIG. 3 is a detailed configuration circuit diagram for explaining the operation of the interpolation calculation circuit 31 shown in the figure. 1...Control panel, 2...C
PU, 3...Non-volatile 1 frame memory for storing correction data of adjustment points, 5, 6, 7.8...
・D/A converter, 9, 10, 11.12...Low pass filter (L, P, F), 13, 14, 15.1
6...Current amplifier, 21...Cursor key, 22...Selection key, 23...Data writing key, 26...Various controls circuit, 2
7... Kuromeno 1tsuchi generator, 28...
・Cross hatch signal, 29... displayed on the screen. Crosshatch signal, 30...kernoll. Name of agent: Patent attorney Toshio Nakao and 1 other person
Figure 7 column

Claims (1)

[Claims] Means for inputting position information of a plurality of convergence adjustment points in the horizontal and vertical directions on the screen of a color television receiver, means for correcting convergence deviation of the adjustment points, and means for generating a convergence correction pattern. and a means for calculating correction data corresponding to the scanning line between the adjustment points in the vertical direction by approximate calculation from the correction data of the adjustment points and writing it into a one-frame memory; A digital convergence device characterized by comprising means for reading correction data corresponding to a scanning line between points.