JPS63122391A - Digital convergence device - Google Patents

Abstract

PURPOSE:To eliminate an error correction data input and a writing malfunction and to attain a stable and highly accurate convergence adjustment by executing the writing operation of a storing means only at the time of the convergence adjustment in which a convergence adjusting pattern is projected on a screen. CONSTITUTION:At the time of the convergence adjustment, a cross hatch signal is outputted from a signal switching circuit 19 according to a control signal supplied to a control terminal 21 and a cross hatch pattern is projected on a projection screen. The control signal from the control terminal 21 is supplied to a writing operation control part 20. The signal from the writing operation control part 20 is supplied to a writing address control part 8 and only at the time of the convergence adjustment, the address is set. Thereby, a convergence dislocation due to the malfunction of a control panel and the writing malfunction due to an external noise are eliminated to execute the stable and highly accurate convergence adjustment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for correcting the convergence of a color television receiver, and more particularly to a digital convergence device that can be adjusted with high accuracy, has stable device operation, and is highly reliable. It is.

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 a projected screen, but in this case, accurately aligning the three colors, that is, convergence adjustment, is an important issue that affects image quality. become.

Here, the convergence shift will be explained using a projection type color television receiver as an example. - In Figure 6, 1 indicates a projection screen for projecting images. 2.3.4 is a projection type picture tube equipped with an optical lens that focuses the image obtained on the fluorescent surface onto the projection screen 1, and each fluorescent surface has three-color images of red, green, and *. is obtained. As shown in Figure 6, 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 6. . In FIG. 6, a solid line 31 is a raster projected by the picture tube 3 of green light, a broken line 41 is a raster projected by the picture tube 4 of blue light, and a dashed line 2
1 shows a raster projected by the picture tube 2 of red light. In order to correct this positional deviation, a convergence adjustment coil is provided in the projection picture tube 2, 3.4 separately from the main deflection yoke.
A sawtooth wave current with a horizontal scanning period is amplitude modulated with a vertical period,
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.
Since the convergence changes due to variations in the configuration of the optical lens system, fluctuations in the projection screen position, etc., it is impossible to perform highly accurate convergence adjustment with a combination of a sawtooth 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 to drive the read address control section 6. The pulse from the read address control section 5 is used to drive the crosshatch generator 6 to project a crosshatch pattern on the projection screen. On the other hand, the address key of the control panel 12 is used to designate a cross point at a position requiring convergence correction, and the position address is set in the write address control unit 8. Next, select the color you want to correct, for example, control panel 12.
While looking at the screen, press the red data write key provided on the
1 frame memory 1 through data reversible counter 11
Write the correction amount in o.

Normally, the multiplexer 9 performs switching control such that writing into the one-frame memory 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, one frame memory is read by the read address control section 5 for the cross position of each crosshatch on the screen. In step 13, the correction amount for each vertical scanning line between crosshatches, that is, for each scanning line for which no correction amount is stored, is determined by, for example, linear approximation. Next, the output signal is converted into an analog quantity by the D/MU converter 14. Next, the correction amount in the horizontal direction is smoothed through a low-pass filter (LPF) 15, and a correction current is applied to the output amplification section 1θ and supplied to the convergence coil 17. The invergence adjustment of each adjustment point is performed as described above.

Problems to be Solved by the Invention However, in the configuration described above, the writing operation to the one frame memory 1o is always performed, so for example, when the video signal is being projected on the projection screen, it is necessary to operate the control panel. This also solves the problem of the digital convergence device malfunctioning due to external noise such as internal discharge of the CRT or fluctuations in power supply voltage, resulting in convergence deviations due to changes in the correction data at each adjustment point. had.

In view of the above, it is an object of the present invention to provide a digital convergence device that eliminates convergence deviations caused by erroneous operation of a control panel and that always operates stably even in the face of external noise.

Means for Solving the Problems The present invention provides storage means for digitally storing convergence correction amounts for adjustment points, switching means for switching and displaying convergence adjustment patterns and input video signals, and writing in the storage means. a control means for controlling the switching means to perform a writing operation only when a convergence tone pattern is displayed; and a reading means for the storage means to read out the convergence correction amount in response to a synchronization signal of the receiver. It is a digital convergence device equipped with

According to the above-described configuration, the present invention performs the writing operation of the storage means only during convergence adjustment when the convergence adjustment pattern is projected on the screen, thereby controlling (7) when the input video signal is projected on the screen. Stable and accurate convergence adjustment can be performed by eliminating changes in correction data due to panel operations and write malfunctions due to external noise.

Embodiment FIG. 1 shows a block diagram of a digital convergence device according to 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, 19 is a signal switching circuit that switches between the crosshatch signal of the convergence adjustment pattern and the video signal from the input terminal 22, and 20 is a write operation control section that controls the write operation to the 1-frame memory 1o. .

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

The crosshatch signals for convergence adjustment from the crosshatch generators are supplied to the signal switching circuit 19, and the input video signal from the input terminal 22 is switched by the control signal from the control terminal 21.

As the control signal supplied to the control terminal 21, for example, a signal from a signal mode changeover switch of a television receiver is input. The signal from the signal switching circuit 19 is supplied to the video circuit 7, and an image is projected on the projection screen.

During convergence adjustment, a crosshatch signal is output from the signal switching circuit 19 in response to a control signal supplied to the control terminal 21, and a crosshatch pattern is projected on the projection screen. - A control signal from the force control terminal 21 is supplied to the write operation control section 20. The signal from the write operation control section 2o is supplied to the write address control section 8, and the address is set only during convergence adjustment.

As explained in the conventional example shown in FIG. 4, the correction amount for each adjustment point is written in the one frame memo +)10. Reading of the one frame memory 10 is performed by the read address control section 6, and the vertical interpolation processing section 13 calculates the amount of correction between the vertical scanning lines between the adjustment points, that is, the scanning lines for which no correction amount is stored. For example, it is determined by linear approximation. Next, the output signal is converted into an analog quantity by the D/MU converter 14. Next, the correction amount in the horizontal direction is smoothed through a low pass filter (LPF) 15, and a correction current is supplied to the output amplification section 1e to supply the convergence coil 17. In the manner described above, convergence adjustment at each adjustment point can be performed.

Next, when the convergence adjustment is not performed, that is, when it is desired to display the input video signal, the video signal is output from the signal switching circuit 19 in accordance with the control signal from the control terminal 21.
An input video signal is projected onto a projection screen. - A control signal from the force control terminal 21 is supplied to the write control section 20. The signal from the write operation control section 2o is supplied to the write address control section 8, and the one frame memory 10
Only the write operation to is stopped. Reading from the one-frame memory 10 is performed in the same manner as described above, so a description thereof will be omitted.

As described above, according to this embodiment, by providing the write operation control unit 2o so that the write operation of the one frame memory 1o is performed only during convergence adjustment, it is possible to prevent convergence deviation due to incorrect operation of the control panel and write due to external noise etc. It is possible to eliminate malfunctions and perform stable and accurate convergence adjustment.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, according to the present invention, it is possible to eliminate error correction data input and write malfunctions, and perform stable and accurate convergence adjustment, which has great practical effects.

[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 principle diagram showing the principle of a projection television receiver, FIG. 3 is a diagram explaining the convergence deviation, and FIG. FIG. 4 is a block diagram of a conventional digital convergence device. 6... Read address control section, 6...
・Crosshatch generator, 8...Write address control unit, 1o...1 frame memory, 19.
...Signal switching circuit, 2o...Writing operation control section.

Claims (1)

[Claims] generating means for generating a convergence adjustment pattern having a plurality of convergence adjustment points in the horizontal and vertical directions on the screen of a color television receiver; input means for inputting position information of the adjustment points; and convergence adjustment patterns for the adjustment points. storage means for digitally storing correction amounts; switching means for switching and displaying the convergence adjustment pattern and the input video signal; and writing in the storage means when the switching means displays the convergence adjustment pattern. 1. A digital convergence device comprising: a control means for controlling the write operation to be performed only by the receiver; and a reading means for reading the convergence correction amount from the storage means in response to a synchronization signal of a receiver.