JPH0429191A - Display device - Google Patents

Abstract

PURPOSE:To adjust the display position of a horizontal image to the center of a cathode-ray tube by detecting the phase difference between a saw-tooth wave current and a color pattern signal and shifting the phase of a synchronizing signal with the output signal of the detection. CONSTITUTION:The display device is equipped with a phase difference detecting means 15 which detects the phase difference between the saw-tooth wave current outputted by a deflecting means 7 with the synchronizing signal generated by a signal source 11 and the color pattern signal indicating the start and end of the brightness information of a brightness signal generated by a signal source 11 and a phase shifting means 6 which shifts the phase of the synchronizing signal with the output signal of the phase difference detecting means 15. Then the phase of the synchronizing signal is shifted according to the phase difference between the pulse signal and color pattern signal. Consequently, the display position of the horizontal image on the cathode-ray tube display 10 is adjusted to the center of the cathode-ray tube 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a display device used in computer output devices, word processors, and the like.

2. Description of the Related Art Conventionally, a display device has been provided with an adjustment function for adjusting the display position of an image.

A conventional display device will be explained below.

FIG. 3 is a block diagram of a conventional display device.

In FIG. 3, 22 is a cathode ray tube display, 1 is a computer, and 23 is a video board that produces a signal for sending output information from the computer 1 to the cathode ray tube display 22.

In the video board 23, 2 is a luminance signal generation circuit that generates a luminance signal for sending the output information of the computer 1 to the cathode ray tube display 22, and 3 is a luminance signal generating circuit that generates a dot clock signal that is the basis of the horizontal synchronization signal and the vertical synchronization signal. The dot clock generation circuit 24 is a timing signal generator circuit that generates a vertical synchronization signal and a horizontal synchronization signal using the dot clock signal.

In the cathode ray tube display 22, 4 is a cathode ray tube, and 5 is a deflection yoke. Reference numeral 6 denotes a phase shift circuit for adjusting the display position of the horizontal image by shifting the phase of the horizontal synchronization signal. When a voltage is applied to this phase shift circuit 6, the phase shift circuit 6 shifts according to the applied voltage. Shift the phase. 25 is a horizontal position adjustment volume, and by turning this horizontal position adjustment volume 25, the phase shift circuit 6 (
:The applied voltage changes. 7 is a horizontal deflection circuit which generates a sawtooth wave current from a horizontal synchronizing signal and supplies it to the deflection yoke 5. 8 is a vertical deflection circuit which generates a sawtooth wave current from a vertical synchronizing signal and supplies it to the deflection yoke 5. Reference numeral 9 denotes a vertical centering circuit that superimposes a DC current on the sawtooth wave current output from the vertical deflection circuit in order to adjust the display position of the image in the vertical direction.
, the vertical centering circuit 9 superimposes a direct current depending on the applied voltage. 26 is a vertical position adjustment volume, and by turning this vertical position adjustment volume 26, the voltage applied to the vertical centering circuit 9 changes.

A method for adjusting the display position of an image on the display device configured as described above will be described below.

The output information of the computer 1 is displayed on the cathode ray tube 4 of the cathode ray tube display 22 using the luminance signal, horizontal synchronization signal, and vertical synchronization signal generated by the video board 23, but the display position of this image is determined by the luminance signal and the luminance signal. It is determined by the phase relationship between the horizontal synchronization signal and the vertical synchronization signal.

First, when the user of the computer 1 adjusts the display position of the image in the horizontal direction to be at the center of the cathode ray tube 4, the user turns the horizontal position adjustment volume 25 and applies a voltage to the phase shift circuit 6. The phase shift circuit 6 shifts the phase of the horizontal synchronization signal according to this applied voltage. By this phase shift, the display position of the image is adjusted to be at the center of the cathode ray tube 4.

Next, when adjusting the display position of the vertical image to be at the center of the cathode ray tube 4, the user turns the vertical position adjustment volume 26 and applies a voltage to the vertical centering circuit 9. In response to this applied voltage, the vertical centering circuit 9
A direct current is superimposed on the sawtooth wave current output by the vertical deflection circuit 8. By superimposing this direct current, the display position of the image is adjusted to be at the center of the cathode ray tube 4.

Problems to be Solved by the Invention However, in the conventional configuration described above, not only does the phase timing of the luminance signal, horizontal synchronization signal, and vertical synchronization signal vary depending on the video board, but also the phase timing varies due to switching of the scanning frequency of the video board. Since the timing changes, the video display position changes by switching the video board or the scanning frequency of the video board. Therefore, each time the video board is replaced or the scanning frequency is switched, the user turns the horizontal position adjustment volume and vertical position adjustment volume while watching the video display position to adjust the video display position to the center of the cathode ray tube. The problem was that it needed to be done.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a synchronization signal generated by a signal source to determine the beginning and end of the luminance information of the sawtooth wave current output from the deflection means and the luminance signal generated by the signal source. The synchronization signal includes a phase difference detection means for detecting a phase difference with a color pattern signal indicating the synchronization signal, and a phase shift means for shifting the phase of the synchronization signal based on the output signal of the phase difference detection means.

Operation The present invention shifts the phase of the synchronization signal according to the phase difference between the pulse signal and the color pattern signal using the above-described configuration.

Embodiment FIG. 1 is a block diagram of a display device in an embodiment of the present invention.

In FIG. 1, l is a computer, 2 is a luminance signal generation circuit, 3 is a dot black generator circuit, 4 is a cathode ray tube, and 5
is a deflection yoke, 6 is a phase shift circuit, 7 is a horizontal deflection circuit, 8 is a vertical deflection circuit, and 9 is a vertical centering circuit. These are the same configurations as the conventional example shown in Fig. 3, so a detailed explanation will be provided. omitted. 10 is a cathode ray tube display, and 11 is a video board that generates a signal for sending output information from the computer 1 to the cathode ray tube display 10.

In the video board 11, 12 is a timing signal generator circuit that generates a vertical synchronization signal, a horizontal synchronization signal, a front porch signal, and a bag porch signal using a dot clock signal; 13 is a timing signal generator circuit that generates a vertical synchronization signal, a horizontal synchronization signal, a front porch signal, and a bag porch signal; This is a white pattern signal generator circuit that generates a white pattern signal with all white information from the beginning to the end.

In the cathode ray tube display 10, 14 is a clock signal generation circuit that generates a clock signal, and 15 is a clock signal generator that clocks the phase difference between the flyback pulse signal and the white pattern signal generated when the horizontal deflection circuit 7 supplies a sawtooth wave current to the deflection yoke 5. 16 is a jitter correction circuit that corrects jitter in the count signal; 17 is a digital circuit that converts the jitter-corrected count signal into voltage and outputs it to phase shift circuit 6; /Analog conversion circuit.

18 is a phase difference detection circuit that counts the phase difference between the vertical output pulse signal and the white pattern signal generated by the vertical deflection circuit 8 supplying the sawtooth wave current to the deflection yoke 5, using the clock signal as a reference, and outputs a count signal; 19 is a count value correction circuit that corrects the count value of the count signal according to the scanning frequency; 20 is a jitter correction circuit that corrects jitter of the count signal; and 21 is a vertical centering circuit 9 that converts the count signal after jitter correction into a voltage. This is a digital/analog conversion circuit that outputs to

Regarding the display device configured as described above, the operation of adjusting the display position of an image will be described below.

The video board 11 uses the timing signal generator circuit 12 based on the dot clock signal as shown in FIG. 2(b).
As shown in (c), (d), and (e), a horizontal synchronization signal, a vertical synchronization signal, a front porch signal, and a bag porch signal are generated. The white pattern signal generator circuit 13 generates a white pattern signal in which all of the luminance information from the beginning to the end of the luminance signal is converted into white information from the front porch signal and the bag porch signal as shown in FIG. 2(d), and generates a cathode ray. It is output to the tube display 10.

In the cathode ray tube display 10, when adjusting the horizontal display position of the image to be at the center of the cathode ray tube 4, the horizontal synchronizing signal sent from the video board 11 via the phase shift circuit 6 is The phase difference between the flyback pulse signal and the white pattern signal generated by creating a wave current and supplying it to the deflection yoke 5 is shown in Figure 2 (a).
) (f) As shown in (g), a clock signal outputted between the center between the flyback pulse signal and the next flyback pulse signal and the center between the output of the white pattern signal E. In order to count this, the phase difference detection circuit 15 first counts the clock signal that is output to A between a flyback pulse signal and the next flyback pulse signal.

Next, the clock signal output to B is counted while the white pattern signal is being output. Furthermore, the clock signal outputted to C between the falling edge of the flyback pulse signal and the rising edge of the white pattern signal is counted. These AX
From the count value of BXC, the count value of E is outputted from the phase difference detection circuit 15 as E=A/2−(C+B/2). The jitter of this count signal is corrected by the jitter correction circuit 16, and the voltage is converted to a voltage by the digital/analog conversion circuit 17 and applied to the phase shift circuit 6. The phase shift circuit 6 shifts the phase of the horizontal synchronizing signal in accordance with this applied voltage. This phase shift adjusts the horizontal image display position to the center of the cathode ray tube 4.

When adjusting the display position of the vertical image to be at the center of the cathode ray tube 4, a sawtooth wave current is generated in the vertical deflection circuit 8 based on the vertical synchronization signal sent from the video board 11 and deflected via the vertical centering circuit 9. The phase difference between the vertical output pulse signal and the white pattern signal generated by supplying it to the yoke 5 is determined by comparing the vertical output pulse signal and the next vertical output pulse signal as shown in FIGS. 2(a), (f), and (h). The phase difference detection circuit 18 first detects the vertical output pulse signal and the next vertical output pulse in order to count it as a clock signal output to K between the center between the center and the center during which the white pattern signal is output. Count the clock signal output to H during the signal. Next, the clock signal output to I is counted while the white pattern signal for one screen is being output. Further, the clock signal outputted to J between the falling edge of the vertical output pulse signal and the rising edge of the white pattern signal is counted. From these count values of H, I, and J, the count value of K is outputted from the phase difference detection circuit 18 as K=H/2−(J+I/2). After the count value of this count signal is corrected in accordance with the scanning frequency in a count value correction circuit 19, the jitter is corrected in a jitter correction circuit 20, and it is converted into a voltage by a digital/analog conversion circuit 21 and sent to the vertical centering circuit 9. applied. The vertical centering circuit 9 superimposes a direct current on the sawtooth wave current output from the vertical deflection circuit 8 in accordance with this applied voltage. By superimposing this direct current, the display position of the image is adjusted to be at the center of the cathode ray tube 4.

Here, the reason why the count value outputted from the phase difference detection circuit 18 only needs to be corrected by the count value correction circuit 19 when adjusting the display position of the image in the vertical direction is as follows.

In other words, if the display position of the image of the cathode ray tube 4 is shifted by the same amount at different scanning frequencies, the value of the DC current superimposed on the sawtooth current will not change even if the scanning frequency is different, but the vertical output pulse and the white pattern will be different. This is because the phase difference with the signal becomes smaller as the scanning frequency becomes higher, and the count value of the phase difference becomes smaller.

In this embodiment, when adjusting the display position of the horizontal image to be at the center of the cathode ray tube 4, the phase of the horizontal synchronizing signal is shifted in accordance with the phase difference between the flyback pulse signal and the white pattern signal. The horizontal image display position is adjusted to be at the center of the cathode ray tube 4, but this can also be adjusted by superimposing a DC current on the sawtooth wave current output by the horizontal deflection circuit 7.

In addition, when adjusting the display position of the vertical image to be at the center of the cathode ray tube 4, the sawtooth wave current output from the vertical deflection circuit 8 is adjusted according to the phase difference between the vertical output pulse signal and the white pattern signal. By superimposing a direct current, the display position of the image is adjusted to the center of the cathode ray tube 4, but this can also be adjusted by shifting the phase of the vertical synchronization signal.

Effects of the Invention As described above, the present invention combines the sawtooth wave current output from the deflection means from the synchronization signal generated by the signal source and the color pattern signal indicating the start and end of the luminance information of the luminance signal generated by the signal source. By including a phase difference detection means for detecting a phase difference and a phase shift means for shifting the phase of a synchronization signal using the output signal of the phase difference detection means, synchronization can be performed according to the phase difference between a pulse signal and a color pattern signal. It is now possible to shift the phase of the signal, making it possible to replace the video board,
When switching the scanning frequency of the video board, there is no need to adjust the display position of the video to the center of the cathode ray tube.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a display device according to an embodiment of the present invention, FIG. 2 is a timing chart of a display device according to an embodiment of the present invention, and FIG. 3 is a block diagram of a conventional display device. 1...Computer 2...Brightness signal generation circuit 3...Dot clock generation circuit 4...Cathode ray tube 5...Deflection yoke 6...Phase shift circuit 7...Horizontal deflection circuit 8... - Vertical deflection circuit 9...Vertical centering circuit 10...Cathode ray tube display 11...Video board 12...Timing signal generator circuit 13...
White pattern signal generator circuit 14...Clock signal generation circuit 15...Phase difference detection circuit 16...Jitter correction circuit 17...Digital/analog conversion circuit 18...Phase difference detection circuit 19...Count Value correction circuit 20...Jitter correction circuit 21...Digital/analog conversion circuit 22...Cathode ray tube display 23...Video board 24...Timing signal generator circuit 25...
Horizontal position adjustment volume 26... Vertical position adjustment volume

Claims (2)

[Claims] (1) It has a cathode ray tube, a deflection yoke attached to the cathode ray tube, and a deflection means for supplying a sawtooth wave current to the deflection yoke from a synchronization signal generated by a signal source, and is output from the deflection means. phase difference detection means for detecting a phase difference between a sawtooth wave current and a color pattern signal indicating the start and end of luminance information of the luminance signal generated at the signal source; A display device comprising: a phase shift means for shifting the phase shift means. (2) comprising a cathode ray tube, a deflection yoke attached to the cathode ray tube, and a deflection means for supplying a sawtooth wave current to the deflection yoke from a synchronization signal generated by a signal source; a phase difference detection means for detecting a phase difference between a pulse signal generated by supplying a sawtooth wave current and a color pattern signal that colors the entire displayable area of an image generated by the signal source; and an output of the phase difference detection means. 1. A display device comprising: centering means for superimposing a direct current on a sawtooth wave current according to a signal.