JPS6211394A - Digital convergence device - Google Patents

Abstract

PURPOSE:To attain an excellent adjusting throughout the entire screen by projecting auxiliary adjusting patterns in the peripheral part of the screen and in the middle of the neighboring adjusting points of a pattern that shows plural convergence adjusting points. CONSTITUTION:Correction at every adjusting point is achieved in such a manner that the convergence correction amount in one of the adjusting points that are displayed as crossing points of cross hatching patterns of heavy line on the screen is selected by means of a cursor key 17 provided on a control panel 1 to be written in a one-frame memory 3 and at the same time, the color is selected by means of a write key 18. When adjusting the correction amount for an adjusting point outside the screen, the adjusting is achieved while watching an auxiliary cross hatching pattern. Correction between the adjusting points is executed in such a manner that the difference between the correction amount of a first line and that of a second line is obtained by a subtraction circuit 5, which is multiplied by the weighting coefficient of each scanning line written beforehand in a coefficient ROM 7 by a multiplier circuit 6, and its result and the correction amount of the second line are added with each other by an adding circuit 8, and is inserted. The output is converted to an analog amount by a D/A converter 9, smoothened, and supplied to the convergence yoke.

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 for a color television receiver.

Conventional Technology As is well known, the shadow mask type color cathode ray tube (hereinafter abbreviated as CRT) used in general color television receivers has three electron guns: red, green, and blue. . However, since it is structurally impossible to arrange all of these plurality of electron guns on the central axis of the CRT, they are mounted slightly away from the central axis or 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,
At the same time, red, green, and blue fluorescent dots are emitted through the same hole, 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, CR
At locations other than the central axis of T, the three electron beams converge in front of the shadow mask. Therefore, the three electron beams cannot pass through the same hole at the same time, and the reproduced image has a larger color shift or convergence shift as it moves away from the center of the screen.

In order to prevent such inconveniences, it is necessary to perform convergence correction so that the three electron beams converge at the shadow mask over the entire screen.In addition, three CRTs that emit the three primary colors are used to expand the image onto the screen. In a projection type color receiver that projects images, CR
Since the angle of incidence of T on the screen is different for each CRT, color shift occurs on the screen.

So-called convergence correction, which superimposes images of these three primary colors on the screen, is generally performed using horizontal flybank pulses and vertical deflection waveforms.

A method of obtaining a convergence correction waveform in an analog manner using a passive element such as R has been adopted, but there is a problem in terms of convergence accuracy. On the other hand, as a method of performing convergence with higher precision, a method of performing convergence correction digitally has been proposed, for example, as shown in US Pat. No. 3,943,279.

In the above conventional example, the concept is to project a convergence correction pattern such as a crosshatch or dot on the screen,
The data of the convergence correction amount for each point is digitally written into one frame memory, this information is read and written in synchronization with horizontal scanning and vertical scanning, and D/A conversion is performed.
This is to perform convergence correction. A detailed explanation will be given below based on FIGS. 4 and 5.

First, as shown in FIG. 5, the hatch generator 16 displays a pattern for convergence adjustment at multiple points on the screen, for example, a crosshatch showing adjustment points in 9 rows horizontally and 7 columns vertically. Use the cursor key 17 of the control spring A/1 to select the adjustment point where you want to adjust the point, which is the intersection of the cross hatches. The address of the adjustment point selected with the cursor key 17 is stored in the cursor counter 13. Next, while observing the convergence state at that adjustment point, select the color you want to correct, for example red, and press key 1.
8, the data reversible counter 2 is incremented by 1, and its output is written to the address specified by the cursor counter 13 in the 1 frame memory 3, which is a data memory for convergence correction.

The contents written in this way to the address selected by the cursor counter 13 are read out again from the one-frame memory 3 to the data reversible counter 2, and if you want to further increase the convergence correction amount, press the write button. 18
When you want to increase the contents of the data reversible counter 2, or conversely, decrease the contents of the data reversible counter 2, the desired data is stored in one frame memory 3.
Write and adjust by writing to. 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 locations corresponding to each adjustment point, it is necessary to perform interpolation for each scanning line between adjustment points in the vertical direction. Therefore, for example, after reading the correction data for the adjustment point in the first column from the 1-frame memory 3 and setting it in the register 4 for 1 horizontal scanning period (1H),
Read the correction data for the adjustment points in the second column from the 1-frame memory 3, and use the correction data in the first and second columns to set the correction data between the adjustment points in the first and second columns. The amount of correction for each included scanning line is determined by interpolation.

That is, the subtraction circuit 6 calculates the difference between the correction amount in the first column and the correction amount in the second column, and the multiplication circuit 6 multiplies the weighting coefficient for each scanning line written in advance in the coefficient ROM 7. and the correction amount in the second column are added together in an adding circuit 8 to perform interpolation. Next, the output signal of the adder circuit 8 is transferred to a D/A converter 9.
Convert it to an analog quantity with low pass filter (LPF) 1
smoothed with 0 and supplied to the convergence yoke after amplification
The same applies to the other green and blue colors.

In the conventional apparatus described above, since each adjustment point can be corrected independently, convergence correction can be performed with high accuracy.

Problems to be Solved by the Invention However, in the conventional configuration as described above, since the adjustment pattern itself can be observed at each adjustment point indicated by the adjustment pattern on the screen, it is possible to accurately adjust the correction. This method has a problem in that it is difficult to improve the convergence accuracy because the necessary correction amount is unclear in the middle part and the peripheral part of the screen where adjustment points are not displayed on the screen. In particular, in high-definition CRT displays and the like, it is necessary to project high-quality images and characters all over the screen, including the periphery of the screen, so the same convergence accuracy is required at the periphery of the screen as at the center. In view of the above-mentioned problems, it is an object of the present invention to provide a digital convergence device that can easily adjust convergence in areas other than adjustment points and around the screen, and can improve accuracy.

Means for Solving the Problems In order to solve the above-mentioned problems, the digital convergence device of the present invention sets the H& convergence adjustment point at a position between adjacent adjustment points of the pattern and at the periphery of the screen. The configuration is such that a plurality of auxiliary adjustment patterns are further projected at the position.

Effect of the Invention With the above-described configuration, the present invention makes it possible to adjust the amount of convergence correction at a predetermined convergence adjustment point on the screen while simultaneously checking the intermediate position of the adjustment point and the auxiliary adjustment pattern at the periphery of the screen. Therefore, it is possible to easily adjust the convergence so that the entire screen is in a good condition overall, and the overall accuracy can be improved.

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 the configuration of a digital convergence device in an embodiment of the present invention.
Reference numeral 1 designates a control panel for inputting adjustment position and correction amount data at the time of convergence adjustment, 2 a data reversible color/column in which the correction amount data is set, and 3 a 1-frame memory for storing convergence correction data. 4
is 1 horizontal scanning period register, 5 is a subtraction circuit, 6 is a multiplication circuit, 7 is a coefficient ROM, and 8 is an addition circuit, these are for creating interpolation data, o9 is a D/A converter, and 1o is a convergence circuit. This is a low-pass filter that outputs a correction waveform. Numeral 11 is a multiplexer that specifies the adjustment point by specifying the address of one frame memory 3, 12 is the overall control circuit, 13 is a cursor counter that specifies the adjustment point, 14 is a comparator for both addresses, and 16 is a read address counter. 016 is a hatch generator that generates a signal for displaying a crosshatch pattern as a convergence adjustment pattern; 17 is a cursor key for inputting an adjustment point;
18 is a data write key for inputting convergence correction data; 19 is an auxiliary hatch generator for generating an auxiliary crosshatch pattern signal for displaying an auxiliary adjustment pattern, which is a feature of this device; and 2o is a mixing circuit.

Figure 2 shows a crosshatch pattern for convergence adjustment showing adjustment points in 9 rows horizontally and 7 columns vertically on the screen, as well as two auxiliary adjustment points at intermediate positions and at the periphery of the screen. FIG. 3 is a front view of the picture tube showing a projection state in which an auxiliary crosshatch pattern is displayed.

FIG. 3 shows a conceptual diagram of one embodiment of this digital convergence device. First, in FIG. 3, reference numeral 21 denotes a video signal input terminal, and the video circuit 22 amplifies the incoming video signal to a required amplitude to drive the CRT 23. The video circuit 22 operates in the same way as a normal television receiver, but is supplied with a crosshatch signal indicating the adjustment point created by the digital convergence circuit 27, which is displayed during convergence adjustment.

25 is a deflection circuit, 29 is a deflection yoke, and synchronization signal input terminal 2
The electron beam of the pcRT 23 is deflected by the synchronization signal that arrives at 4. The control panel 26 corresponds to the control panel 1 in FIG. 1, and includes a cursor key 17 for instructing which position on the screen to perform convergence correction, and a key 18 for writing the correction amount into the digital convergence circuit.
The keys necessary for convergence adjustment are installed.

The digital convergence circuit 27 includes a one-frame memory 3 made of non-volatile memory, stores convergence correction data from the control panel 26, reads out this data, amplifies the current in the output circuit 28, and sends the convergence coil 30 to the convergence coil 30. Convergence is corrected by applying a correction current.

Note that the digital convergence circuit 27 is supplied with a synchronization signal because it needs to operate in synchronization with the deflection. In order to facilitate understanding, convergence of a receiver using a CRT with a delta type electron gun arrangement will be described below.

The Kuromeno-Sochi pattern signal for displaying the convergence adjustment point is generated by the No-Tsuchi generator 16 shown in FIG. The signals are mixed to form a cross-no-cross pattern signal for convergence adjustment. Second
As shown in the figure, the crosshatch pattern indicating the adjustment points is indicated by the intersection of thick lines, and is arranged in 9 rows vertically and 7 columns horizontally on the screen, and two auxiliary Kuromeno-Tsuchi patterns are inserted between each adjustment point. .

Including the screen quality adjustment points, there are 11 rows in the vertical direction and 9 columns in the horizontal direction.

First, we will discuss the correction for each adjustment point.Use the cursor keys 17 on the control panel 1 to determine the convergence correction amount at which position of the adjustment points displayed as intersections of thick crosshatch patterns on the screen as shown in Figure 2. 1
Assume that at the same time as selecting whether to write to the frame memory 3, a color is selected using the write key 18, and red is selected. The cursor keys 17 can be moved up, down, left and right one by one with a thick hatch so that any adjustment point displayed on the screen can be selected.

The address of the dot selected by the cursor key 17 on the 1-frame memory 3 is stored in the cursor counter 14, and the output signal of the cursor counter 14 is added to the 1-frame memory 3 via the address multiplexer 11 to During the retrace period of the machine, the correction amount data written in the 1-frame memory 3 is read out, and the data reversible counter 2
Set to . The 1-frame memory 3 is composed of nonvolatile RAM, and its capacity is 4 types: red, green, blue radial, and blue lateral, assuming that the number of hatches is 11 horizontally x 9 vertically and the correction amount is 8 bits. There is a total of 11 x 9 x 8 x 4 bits. The data reversible counter 2 is used to write the data of the convergence correction amount to the one frame memory 3, and also to modify the contents written to the one frame memory 3. When increasing the
When increasing the contents of the data reversible counter 2 and decreasing the correction amount, the contents of the data reversible counter 2 are sequentially written into the one-frame memory 3. Do the same for all the points that need to be corrected. Here, when adjusting the correction amount of the adjustment point (b) outside the screen, do so while looking at the auxiliary crosshatch pattern (C). Adjust the other screen peripheries in the same way.

As described above, the correction amount corresponding to each adjustment point in the 11th row and 9th column shown in FIG. 2 is written into the one frame memory 3, and convergence correction is performed at each adjustment point. However, no correction is made between adjustment points. So, if we assume that the scanning line contains water between the adjustment points in the vertical direction, then 1
It is necessary to generate correction data corresponding to M scanning lines between adjustment points with no data from the correction amounts of adjustment points written in the frame memory 3. Therefore, for example, the correction amount of the adjustment console in the first row is read out from the 1-frame memory 3, and 1
After setting it in the H register 4, the correction amount of the adjustment point in the second column is read from the one frame memory 3, and the difference between the correction amount in the first column and the correction amount in the second column is determined by the subtraction circuit 5. , a weighting coefficient for each scanning line written in advance in the coefficient ROM 7 is multiplied by a multiplication circuit 6 to obtain a variation for each scanning line, and an addition circuit 8 adds this variation and the correction amount for the second column. Perform interpolation accordingly. Next, the output signal of the adder circuit 8 is
/A converter 9 converts it into an analog quantity.

Since the output signal waveform of the D/A converter 9 has a staircase waveform, a low-pass filter (LPF) is used for correction between adjustment points in the horizontal direction.
)10 to obtain a smooth convergence correction waveform.

Note that since the operation of the one-frame memory 3 needs to be performed in accordance with the screen, horizontal and vertical synchronization signals are supplied to the control circuit 12.

I have talked about red convergence correction above, but
The same applies to green and blue.

As described above, according to this embodiment, by projecting an adjustment pattern in which two auxiliary crosshatch patterns are superimposed between adjacent crosshatch patterns at a convergence adjustment point, The convergence adjustment of the parts can be easily adjusted and the accuracy can be improved.

In the above embodiment, the electron gun arrangement is a delta type CR.
Although we have described the concept of T, it goes without saying that the idea of the present invention is also effective in a CRT in which the electron gun is arranged in-line, and in a projection type television receiver that uses a plurality of projection type CRTs to configure a large screen television. .

Further, in this embodiment, the adjustment pattern is a crosshatch pattern, but it may also be a dot pattern.

Further, the auxiliary adjustment pattern may be displayed with a different line width or brightness in order to be easily distinguished from the adjustment pattern indicating adjustment.

Effects of the Invention As described above, according to the present invention, an adjustment pattern in which a plurality of auxiliary adjustment patterns are superimposed is projected at a position between adjacent predetermined convergence adjustment points in a digital convergence device or at the periphery of the screen. By doing so, it is possible to adjust the correction amount data of the adjustment points to achieve a good convergence state as a whole while also observing the convergence state of the intermediate position of the adjustment point and the peripheral area of the screen using the auxiliary adjustment pattern. This allows for easy and accurate adjustment.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a digital convergence device according to an embodiment of the present invention, Fig. 2 is a front view showing the display state of the adjustment pattern, Fig. #E3 is a block diagram showing its usage state, and Fig. 4 5 is a block diagram of a conventional digital convergence device, and FIG. 5 is a front view showing the display state of the adjustment pattern. 16... Hatch generator, 19... Auxiliary hatch generator, 2o River... Mixing circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
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Claims (2)

[Claims] (1) means for projecting convergence adjustment patterns at multiple points in the horizontal and vertical directions on the screen of a color television receiver; A means for inputting convergence correction information at a point position, and a correction signal generating means for correcting a convergence shift at each convergence adjustment point based on the convergence correction information read from the convergence correction data memory. . A digital convergence device, further comprising means for projecting a plurality of auxiliary adjustment patterns at positions intermediate between adjacent ones of the plurality of convergence adjustment points and at positions around the screen. (2) Claim 1, characterized in that the auxiliary adjustment pattern has a different line width or brightness that can be distinguished from the pattern indicating the convergence adjustment point.
The digital convergence device described in .