JP2646762B2 - Digital convergence device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for correcting convergence of a color television receiver, and more particularly to a digital convergence device capable of displaying a cursor of an adjustment point outside a screen and performing extrapolation with high accuracy. Things.

2. Description of the Related Art In general, in a projection type color receiver for enlarging and projecting onto a screen using three projection tubes that emit three primary colors,
Since the angle of incidence of the projection tube on the screen is different for each projection tube, a color shift occurs on the screen. The superposition of these three primary colors, so-called convergence, employs a method in which a convergence correction waveform is created in an analog manner in synchronization with the horizontal and vertical scanning periods, and the size and shape of the waveform are changed to adjust the convergence accuracy. There is a problem in the point. Therefore, as a method having high convergence accuracy, for example, a digital convergence apparatus disclosed in Japanese Patent Publication No. 59-8114 has been proposed.

The conventional digital convergence device will be described below. FIG. 3 is a block diagram of a conventional digital convergence device, in which a convergence correction pattern such as a cross hatch pattern (shown in FIG. 4) is projected on a screen, and a convergence correction amount for each adjustment point is shown. Is digitally written into a frame memory, and this data is read out and subjected to digital / analog conversion (hereinafter abbreviated as D / A conversion) to perform convergence correction.

FIG. 3 shows a block diagram of a conventional digital convergence device. In the figure, 1 is a pattern projection circuit, 2
Is a horizontal synchronization signal, 3 is a horizontal address counter circuit, 4 is a vertical synchronization signal, 5 is a vertical address counter circuit, 6 is a read address generation circuit, 7 is a write address generation circuit, 8 is a control panel, 9 is a data reversible counter, 10 is a frame memory control circuit, 11 is a frame memory, 12 is a vertical interpolation circuit, and 13 is a D / A conversion circuit. First, as shown in FIG. 4, for example, a cross hatch signal of 9 rows in the horizontal direction and 7 columns in the vertical direction is projected from the pattern projection circuit 1 on the screen. The horizontal signal H1 of the pattern signal is generated by supplying a horizontal synchronizing signal 2 synchronized with screen scanning to a horizontal address counter circuit 3 composed of a PLL circuit and a frequency dividing circuit. The vertical signal V1 of the pattern signal is reset by a vertical synchronizing signal 4.
And supplied to the pattern projection circuit 1 to be projected. Next, an intersection (hereinafter referred to as an adjustment point) of a crosshatch signal at a location to be corrected and a color to be corrected, for example, red, are selected by a cursor key (not shown) of the control panel 8. The address of the adjustment point selected by the cursor key is stored in the write address generation circuit 7 and supplied to the frame memory 11 via the frame memory control circuit 10, and the correction data of the adjustment point specified by the cursor key is stored in the frame memory.
The data is read from 11 and written to the data reversible counter 9. Further, a write key (not shown) on the control panel 8
Is operated to increase / decrease the data reversible counter 23, and write correction to the frame memory 11 is performed.

Next, reading of the convergence correction data written in the frame memory 11 will be described. The horizontal and vertical addresses corresponding to the screen adjustment points are created and read out by a horizontal address counter circuit 3 receiving a horizontal synchronization signal 2 synchronized with screen scanning and a vertical address counter circuit 5 receiving a vertical synchronization signal 4 as input. The frame memory is supplied to the address generation circuit 6 and transmitted to the frame memory via the frame memory control circuit 10.
In addition to 11, the correction data of each adjustment point is read. Since the frame memory 11 only stores correction data at locations corresponding to the respective adjustment points, the vertical interpolation circuit 12 performs interpolation between the adjustment points in the vertical direction. The vertical interpolation circuit 12 includes a subtraction circuit, a coefficient ROM, a multiplication circuit, an addition circuit, and the like.
The operation is as shown in FIG. 4, for example, a difference is obtained by a subtraction circuit from the correction data of the two adjustment points of the second row P1 and the third row P2, and the scanning line previously written in the coefficient ROM is obtained. Is multiplied by a multiplication circuit, and the result is added to the correction data of the second row P1 by an addition circuit to perform interpolation. The output of the vertical interpolation circuit 12 operating as described above is
The signal is converted into an analog quantity by the A conversion circuit 13 to obtain a staircase wave-like signal. The signal between the horizontal adjustment points is supplied to a convergence yoke after the correction amount of the adjustment point of each row is smoothed by a low-pass filter (not shown) and amplified.

As described above, according to the conventional method, each adjustment point can be independently corrected, so that convergence correction can be performed with high accuracy.

However, in the digital convergence device configured as described above, the convergence adjustment can be performed with high accuracy. Since the cursor is displayed at the position of the extrapolation point, when the deflection amplitude of the projection television receiver is overscanned, the cursor display of the extrapolation point becomes invisible and cannot be adjusted. In addition, since the extrapolation point correction data is obtained from the correction data from the adjustment point in the screen, the extrapolation point adjustment must be performed at the end, and for that purpose, a current amplification stage for driving the convergence yoke is provided. There was a problem that a wideband amplifier was required. Therefore, the current amplification stage has a problem of extremely large power consumption.

In view of this, the present invention makes it easy to see the cursor position,
It is another object of the present invention to provide a digital convergence device capable of performing highly accurate correction.

Means for Solving the Problems To solve the above problems, the present invention provides a means for generating a plurality of convergence adjustment points in the horizontal and vertical directions on a screen of a color television receiver and displaying a cursor, and displaying the cursor. Means for digitally storing the convergence correction amount for each adjustment point, means for converting this digital amount to an analog amount, means for driving and correcting the convergence yoke with the analog signal, Means for detecting the level of the analog signal from the maximum value to the minimum value and outputting a level detection signal; and displaying the cursor display area in a screen area corresponding to a correction range based on each adjustment point based on the level detection signal. Means.

The present invention displays the correction range, which is a dynamic range, on the screen by displaying the cursor display area in the screen area corresponding to the correction amount from the maximum value to the minimum value of the correction range based on each adjustment point. Therefore, high-precision correction can be realized without troublesome initial adjustment operation. In addition, since a cursor such as a square or a circle can be displayed on the basis of the adjustment point, the cursor position can be recognized at a glance and the adjustment time can be reduced. Further, since the convergence accuracy between the adjustment points can be confirmed by displaying the cursor of the square or the circle, the correction can be performed with high accuracy.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention, in which a cursor is displayed in a screen area corresponding to the correction amount from the maximum value to the minimum value of the correction range based on each adjustment point. Things. In FIG. 1, reference numeral 21 denotes an address control unit for controlling read / write of a memory, and 23 detects a maximum value and a minimum value of a correction amount converted into an analog signal from the D / A conversion circuit 13, and detects a level. A level detection circuit 24 for outputting a signal is a cursor generator for controlling the range of a cursor display area based on the level detection signal. In FIG. 1, components operating in the same manner as in FIG. 3 of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

In order to explain the digital convergence device of this embodiment in detail, a display screen diagram and a correction data diagram of FIG. 2 will be used. FIG. 7A is a screen view when the convergence correction in the vertical direction at the adjustment point D is performed, and the broken line at the adjustment point D indicates the position of the cross hatch signal 50 when the correction is performed. In the case of the maximum correction amount that can be corrected in the vertical direction, the maximum value of the correction data from the D / A conversion circuit 13 is detected by the level detection circuit 23, and this detection signal is supplied to the cursor generation circuit 24. Then, it is set so that the cursor is generated at the screen position corresponding to the maximum correction amount in the vertical direction. Therefore, as shown in FIG. 2A, a square cursor is displayed in a range corresponding to the position of the maximum correction amount. Similarly, when the horizontal convergence correction shown in FIG. 2 (b) is performed, the maximum value of the correction data from the D / A conversion circuit 13 is detected by the level detection circuit 23, and this detection signal It is supplied to the device 24 and is set so that a cursor is generated at a screen position corresponding to the maximum correction amount. Therefore, a square cursor is displayed in the range corresponding to the position of the maximum correction amount in the horizontal direction as shown in FIG. This means that the correctable range can be seen at a glance on the screen, so that the correction data overflows and there is no need to adjust again.

Next, a detection signal for performing level detection will be described in detail. The maximum correction amount on the display screen is determined by the number of quantization bits in the memory and the amount of amplification after being converted into an analog signal. Therefore, when an 8-bit memory is used as shown in FIG. 2 (c) as a detection signal for performing level detection, signals from correction data 0 to 256 around the correction data 128 are used as detection signals. And the range of the cursor display area is determined according to the state. This detection signal is set to be output, for example, during a vertical blanking period or during initial adjustment. D /
In order to detect the level of the analog signal from the A conversion circuit 13, since the gain of the output amplification unit 16 in the subsequent stage is constant,
This is because the D / A stage can be used instead. Therefore, the cursor display can be used by displaying an area indicating the correction range of the convergence correction in addition to the determination of the position of the adjustment point.

As described above, according to the present embodiment, the cursor display area is displayed at the screen position corresponding to the correction amount from the maximum value to the minimum value of the correction range based on the adjustment point, so that the position of the adjustment point can be determined. Since the correction range, which is the dynamic range, can be displayed on the screen, the adjustment can be performed in a short time, and the convergence accuracy between the adjustment points can be confirmed, so that high-precision correction can be performed.

Although the projection type color receiver has been described in the embodiment for easy understanding, it is needless to say that the invention is also effective for a shadow mask type direct-view type receiver.

Further, in the embodiment, the extrapolation operation means has been described as an operation method based on linear approximation.

Further, in the embodiment, the case where the cursor is displayed in a rectangular area has been described, but the cursor may be displayed in other shapes.

Effect of the Invention As described above, according to the present invention, by displaying the cursor display area on the screen area corresponding to the correction amount from the maximum value to the minimum value of the correction range based on the adjustment point,
The dynamic range setting and correction sensitivity setting at the time of initial adjustment can be checked at a glance with the cursor display, so it can be set without having to perform initial adjustment operations, and in particular, vertical raster unevenness caused by the vertical quantization bit number etc. Since the screen disturbance can be reduced, highly accurate convergence correction can be realized in a short time. In addition, since a cursor display method of a square or a circle based on the adjustment point can be performed, the cursor position can be recognized at a glance, and the adjustment time can be greatly reduced. In addition, since the convergence accuracy between the adjustment points can be confirmed by the cursor display of the square or the circle, the correction can be performed with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital convergence device according to one embodiment of the present invention, FIG. 2 is a display screen diagram and a detection data diagram for explaining the operation of the embodiment, and FIG. 3 is a conventional digital convergence device. FIG. 4 is a block diagram of the apparatus, and FIG. 4 is a display screen diagram for explaining the operation of the apparatus. 1 ... pattern detection circuit, 8 ... control panel,
11 ... frame memory, 12 ... vertical interpolation circuit, 21 ... address control unit, 23 ... level detection circuit, 24 ... cursor generation circuit.

Claims (1)

(57) [Claims] 1. A means for generating a plurality of convergence adjustment points in a horizontal and vertical direction on a screen of a color television receiver and displaying a cursor, and digitally storing a convergence correction amount for each adjustment point displayed on the cursor. Means for converting the digital amount into an analog amount, means for driving and correcting the convergence yoke with the analog signal, and detecting the level of the analog signal from the maximum value to the minimum value of the correction amount in the storage means. A digital convergence device comprising: means for outputting a level detection signal; and means for displaying, based on the level detection signal, an area of the cursor display in a screen area corresponding to a correction range based on each adjustment point.