JPH0759091B2 - Digital convergence device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for correcting the convergence of a color television receiver, which can be adjusted with high accuracy and is sufficiently compatible with those having different input sync signal frequencies. It relates to a possible low-cost digital convergence device.

2. Description of the Related Art Generally, in a color television receiver, there are three types of red, green and blue.
An image is created by synthesizing colors on a fluorescent surface or on a projected screen. In this case, accurate alignment of the three colors, that is, convergence adjustment is an important issue affecting image quality.

Here, the deviation in convergence will be described by taking a projection type color television receiver as an example.

In FIG. 2, reference numeral 1 denotes a projection screen for displaying an image, and 2, 3, 4 are projection type cathode ray tubes equipped with optical lenses for forming an image obtained on a fluorescent surface on the projection screen 1, respectively. Images of three colors, red, green, and blue, are obtained on the fluorescent surface. As shown in FIG. 2, when these cathode ray tubes are arranged in the horizontal direction, the projection angles with respect to the projection screen 1 are different from each other, so that the projected raster is displaced for each color as shown in FIG. In FIG. 3, a solid line 3l shows a projection raster of the green light by the cathode ray tube 3, a broken line 4l shows a projection raster of the blue light by the cathode ray tube 4, and a chain line 2l shows a projection raster by the red light of the cathode ray tube 2.

To correct this misalignment, use projection type cathode ray tubes 2, 3, and 4.
In addition to the main deflection coil, a convergence adjusting coil is provided, the sawtooth wave current in the horizontal scanning period is amplitude-modulated in the vertical period, and the amplitude can be adjusted independently for each color.

However, this color shift amount changes due to variations in the mounting position of each cathode ray tube, variations in the configuration of the optical lens system, variations in the projection screen position, and so on. Therefore, in order to perform highly accurate convergence adjustment, a simple sawtooth wave current or , A parabolic current combination is not possible.

As a method for realizing such convergence adjustment, a convergence circuit having a digital correction waveform forming unit is considered.

The conventional digital convergence device will be described in detail below with reference to FIG.

Horizontal and vertical cycle pulses synchronized with the deflection current cycle are applied as synchronization signals, and the read address control unit 5 is driven thereby. The crosshatch pattern generator 6 is driven by using the pulse from the read address control unit 5 to project the crosshatch pattern on the projection screen. FIG. 2 shows a crosshatch pattern. On the other hand, the address key of the control panel 12 is used to specify a cross point (for example, FIG. 4A) at a position where convergence correction is required, and the position address is set in the write address control unit 8. Next, the correction data is written in the one-frame memory 10 through the data reversible counter 11 while looking at the screen with the data write key of the color to be corrected, for example, the red data write key provided on the control panel 12. Normally, the writing in the 1-frame memory is switched and controlled by the multiplexer 9 so as to be performed in the blanking period of the image signal. Therefore, reading is not impaired. The same operation is performed at each adjustment point as described above. Next, the reading of the 1-frame memory 10 is performed by the read address control unit 5 at the cross position of each cross hatch on the screen, and through the register 18 driven by the read control unit 5, vertical interpolation processing is performed. The unit 13 performs a correction amount process in the vertical scanning direction between the cross hatches. Next, the operation of this correction processing will be described with reference to FIGS. The correction amount of each scanning line between A and B or between C and D in FIG. 5 can be obtained from the equation (AB) K + A. Here, K represents a value obtained by linear approximation and is written in the ROM. Therefore, it is clear that K can be obtained from the number N of scanning lines between AB. Further, the number N of scanning lines is obtained from the number of scanning lines M of one field and the horizontal lines of the crosshatch. Next, the correction amount processing between FIG. 5 and AB will be described with reference to FIG. The correction amounts at points A and B read from the one-frame memory 10 by the read address control unit 5 are registered in the registers 1 and 18 and the registers 2 and 19. The output signals of the registers 1 and 2 are subjected to (A-B) calculation by the subtractor 20, sent to the multiplier, multiplied by the coefficient for each scanning line to obtain (A-B) K, and added by the adder 23. (AB) K + A is sent. In this way, the correction amount of the scanning line for which the correction amount is not stored is obtained. Next, the output signal is converted into an amount of analog by the D / A converter 14. Next, it passes through the low-pass filter 15 and is applied to the output amplification circuit section 16 to supply a correction current to the convergence coil 17. Convergence adjustment of each adjustment point is performed as described above.

Problems to be Solved by the Invention However, in the above configuration, when the input sync signals are different (such as different models of PCs or NT
SC and high-definition TV), the amount of convergence correction was adjusted according to the frequency of each input sync signal and stored in multiple frame memories. However, the digital convergence device that supports a variety of diversified signal sources is only compatible with a limited number of signal sources because the capacity of the frame memory increases and the cost increases. Therefore, with respect to frequencies other than the limited frequencies, the convergence, which corresponds to the deflection system of the receiver but requires a highly accurate one, does not operate.

In view of such a point, the present invention has an object to detect the frequency of an input synchronizing signal and inform the user of the apparatus that only a limited synchronizing signal can be used by using the digital convergence apparatus.

Means for Solving the Problems The present invention provides a first screen for displaying a plurality of convergence adjustment points arranged in a grid on a screen of a color television receiver.
Of the display means, an input means for inputting position information of the convergence adjustment point for performing convergence adjustment, and a frequency of a synchronization signal input to the color television receiver,
First detecting means for detecting a frequency within a predetermined range, second detecting means for detecting a frequency outside the predetermined range, and the first
The plurality of storage means for storing the convergence correction amount according to the frequency within the predetermined range detected by the second detection means, and the color television image reception when the second detection means detects a frequency outside the predetermined range. When a frequency within a predetermined range is detected by the second display means for displaying a predetermined image on the screen of the machine and the first detection means, convergence correction according to the frequency detected from the plurality of storage means is performed. The digital convergence device is provided with an output unit that reads out and outputs the amount, and when the second detection unit detects a frequency outside a predetermined range, outputs a constant convergence correction amount.

With the above-described configuration, the present invention displays the screen on the screen when the second detecting means detects the synchronizing frequency, and indicates to the user that the frequency is other than the specified frequency, and allows the digital convergence device to be used correctly. is there.

Embodiment FIG. 1 is a block diagram of a digital convergence device according to an embodiment of the present invention, in which components operating in the same manner as in the conventional example are designated by the same reference numerals and the description of the operation is omitted.

In FIG. 1, 24 is a second frame memory that adjusts and stores the amount of convergence correction when synchronization signals of different frequencies are input, 25 is a second register, and 26 is a second frame memory that detects a limited frequency of the synchronization signal. 1 frequency detection circuit, 27 is the first
Switching device, 28 is a second frequency detection circuit for detecting the outside of the limited frequency range, 29 is a second switching device, 30 is a third switching device, 31 is a constant value output circuit, and 32 is when the outside of the limited range is detected. It is the second display means for output display.

The operation of the digital convergence device having the above configuration will be described.

First, the time of inputting a limited synchronization signal will be described. The limited synchronizing signal is detected by the first frequency detecting circuit 26 as to whether it corresponds to the first frame memory 10 or the second frame memory 24. If the synchronizing signal corresponds to the first frame memory 10, the first switching is performed. Then, if the synchronizing signal corresponds to the second frame memory 24, the first switching device is switched to the side b, and adjustment is performed in the same manner as in the conventional case. At this time, the second switch and the third switch are set to the a side. Next, when a synchronizing signal out of the limited range is input, the second frequency detection circuit 28 operates, the second switch 29 is turned to the low side, and the dot signal of the dot generator of the second display means is displayed. Furthermore the third
The switch 30 is switched to the low side, and the constant value output circuit 31 supplies convergence correction data of a constant value to the convergence coil.

As described above, according to the present invention, the second frequency detection circuit 28 for detecting the frequency of the limited synchronization signal out of the range is provided, and the second display means and the constant value output circuit 3 different from those when the limited synchronization signal is input.
If the first, second and third switching devices 29, 30 are provided and controlled as described above, the user can correctly adjust the digital convergence.

Although the dot signal is generated as the second display means, it may be a color or other display means.

EFFECTS OF THE INVENTION As described above, according to the present invention, the user can correctly adjust the digital convergence device, and the practical effects are large.

[Brief description of drawings]

FIG. 1 is a block diagram of a digital convergence device in one embodiment of the present invention, FIG. 2 is a principle diagram of a projection type color TV receiver, FIG. 3 is a diagram for explaining the convergence deviation, and FIG. FIG. 5 is a block diagram of a conventional digital convergence device, FIG. 5 is a pattern diagram for explaining the device, and FIG. 6 is a partial block diagram for explaining the operation of the device. 5 ... Read-out address control unit, 6 ... First display means, 8
...... Write address controller, 9 …… Multiplexer,
10 …… First frame memory, 11 …… Data reversible counter, 12 …… Control panel, 13 …… Vertical insertion circuit, 18 …… First register, 24 …… Second frame memory,
25 ... second register, 26 ... first frequency detection circuit, 27 ...
… First switch, 28 …… Second frequency detection circuit, 29 …… Second
Switching device, 30 ... 3rd switching device, 31 ... Constant value output circuit, 32
...... Second display means.

Claims (1)

[Claims] 1. A first display means for displaying a plurality of convergence adjustment points arranged in a grid on a screen of a color television receiver and position information of the convergence adjustment points for performing the convergence adjustment. Input means, first detecting means for detecting a frequency within a predetermined range of frequencies of the synchronization signal input to the receiver, second detecting means for detecting a frequency outside the predetermined range, and the first detecting means. The plurality of storage means for storing the convergence correction amount according to the frequency within the predetermined range detected by the first detection means, and the color television when the second detection means detects a frequency outside the predetermined range. When a frequency within a predetermined range is detected by the second display means for displaying a predetermined image on the screen of the receiver and the first detection means, a command corresponding to the frequency detected from the plurality of storage means is detected. Reading and outputting Bazensu correction amount, the second detecting means, when detecting a frequency outside a predetermined range, the digital convergence apparatus and output means for outputting a constant convergence correction amount.