JPS62138891A - Video signal generation circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a video signal generation circuit for a display device using a color CRT, in order to reduce misconvergence due to the difference between the adjustment magnetic field of the CRT and the geomagnetism of the destination area. A delay circuit for correcting the phase is inserted into each color signal system of the video circuit. Accordingly, the present invention relates to a video signal circuit that can reduce CRT misconvergence that occurs in a destination area in a display device using a color CRT.

[Conventional technology] A conventional O1'tT video signal circuit is shown in FIG.

In the figure, 1 is a character generator (CG), 2 is a shift register for parallel-to-serial conversion, and 31132133 is a driver for outputting each color video signal (red, green, blue).

As shown in the figure, the conventional video circuit only sends out red, green, and 1F video signals at the same time, and does not particularly include phase adjustment means for each color signal system of the CRT.

[Problem that the invention seeks to solve]

Since the above-mentioned conventional display device using a color CRT uses an electromagnetic deflection method, misconvergence, that is, deviation of the color video signal, occurs if the destination region is different. For this reason, I will. For this reason, devices shipped to various parts of the world require adjustment for each destination terrestrial magnetic field, which is very complicated in terms of management and cost.

Furthermore, if a misalignment occurs on-site, adjustment requires specialized knowledge, which causes maintenance problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a video signal generation circuit having means for reducing misconvergence that occurs in a destination area in a display device using a color CRT.

[Means for solving problems]

In order to achieve the above object, the present invention provides a method for correcting the phase of each color signal system of the video circuit in order to reduce the generation of misconvergence based on the difference between the adjustment magnetic field of the CRT and the geomagnetism of the destination area. delay circuit 1
21/123 and 122 were inserted.

[For production]

With the above configuration, it is possible to match the phase of the color signal system by adjusting the signal delay circuit in any destination area.

FIG. 1 is a diagram explaining the principle of the present invention. In the same figure, the red or blue serial video signal is transferred to the signal delay circuit 12+/1.
23, an arbitrary delayed signal thereof is selected by a parallel selection switch 13t/j33, and a red/1t video signal is outputted via a drive circuit 31153.

On the other hand, the green serial video signal is input to the signal delay circuit 122, and the delayed signal is outputted as a green video signal via the drive circuit 32. In this case, the signal delay circuit 12
Each output phase of s/123 has a width that can sufficiently correct the misconvergence te with respect to the output phase of the signal delay circuit 122.

〔Example〕

FIG. 2 is an explanatory diagram of the configuration of an embodiment of the present invention.

The difference between this figure and FIG. 4 is a shift register 2 for parallel-to-serial conversion and a driver 311 for outputting each color signal!
+2133, there is provided an AND circuit 11111121113 which is commonly controlled by the output of the shift register 2 and inputs the red, green, and pre-control signals respectively, and a delay line (DL) 121, 122, 123 is provided for this output, respectively.
Connect the rotary switch 131.15 taken out as a tap from the middle part of the delay output of DL 121.123.
z is provided, and these outputs are connected to a waveform shaping driver 141,
14°, and the output of the DL 122 is directly input to the waveform shaping driver 142. Thereafter, red, green, and blue video signals are outputted via drivers 31 to 63. In the figure, the first
The same numbers are given to the parts corresponding to the principle diagram in the figure, and the AND circuit 11. ~113 and waveform shaping drivers 141~143
This is a newly inserted version.

FIG. 3 is an operational waveform diagram of the embodiment of FIG. 2.

Now, suppose that the misconvergence between the red/fr video signal and the green video signal deviates as shown in the same figure (CL) and the same figure (b), then rotary switch 1! By changing +1.132, the phase of the red/blue video signal in (α) in the same figure can be shifted as shown in (c) - ■ in the same figure, and (b) in the same figure.
The phase of the green video signal can be matched within an acceptable range.

By arranging this rotary switch '31.132 at a position that can be adjusted by the operator, it can be easily adjusted while viewing the screen at the installation location.

In addition, if the device has a lock that is sufficiently high speed compared to the video signal, the delay line (DL) 12] to 12
3 and the waveform shaping drivers 141 to 143 can be replaced with three shift registers.

〔Effect of the invention〕

As explained above, according to the present invention, it is suitable for domestic use.

In both overseas and overseas devices, misconvergence based on the difference between the adjustment magnetic field and the earth's magnetism at the installation location can be easily corrected using the same selection switch (rotary switch) on the display. A great advantage is that even if a deviation occurs on-site, it can be easily adjusted by the user.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIG. 6 is an operational waveform diagram of an embodiment of the present invention.
FIG. 4 is an explanatory diagram of the configuration of a conventional example. In the figure, 1 is a character generator (CG), 2 is a shift register for parallel-to-serial conversion, and 61
~63 is a driver, 11, ~113 is an AND circuit, 12
1 to 123 are delay lines, 16. . 16□ is a rotary switch, 14. 143 indicates a waveform shaping driver.

Claims (1)

[Claims] In a video signal generation circuit for a display device using a color CRT, each color of the video circuit is A video signal generation circuit characterized in that delay circuits (12_1 to 12_3) for correcting phases are inserted in each signal system.