JPS61206380A - Image display device - Google Patents

Abstract

PURPOSE:To give no disagreeable feeling to the audience by scanning all width of a horizontal direction of an image receiving tube during projecting an image having a width smaller ratio than a length, forming a raster in all plane of the image receiving tube, and changing a luminance and a color of the right and left ends of the image receiving tube to eliminate a difference from the image in a center section. CONSTITUTION:A deflecting current C has a peak to peak value Iy2 set at a value corresponding to a width of a length to width of 3:5. An inclination in a periods ta1, ta2 except for a retrace line period tr2 in a blanking period (tbl) of an image signal (a) is made larger than the inclination in an image period (tds), and a scanning speed is higher. A current modulating circuit 15 connected to one end of a horizontal deflecting coil 21 has a small impedance when a current level is below Il1 and above Il2, in a scanning period ta2 on displaying the image of an ordinary television system, and produces an adding signal (d) to supply to primary color signal output circuits 12-14. Thereby, in a center section 16a of the image receiving tube 16 of the length and width ratio of 3:5, the image of the length and width ratio 3:4 of the ordinary television system is projected in a normal size, and the luminance of the right and left end sections 16b, 16c is reflected about the same as that of the center section 16a.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image display device, which projects a plurality of types of images with different aspect ratios onto a picture tube corresponding to the image with the largest width-to-height ratio. The present invention relates to a display device.

BACKGROUND OF THE INVENTION Currently, the display screens of normal television broadcasts and various video packages have an aspect ratio of 3=4. However, so-called high-definition television systems with a large number of scanning lines currently under development have an aspect ratio of 3:5.

It is possible to configure an image display device having an aspect ratio of 3:5 for this high-definition television system to display an image having an aspect ratio of 3:4 for normal television broadcasting. In this case, the image of high-definition television broadcasting is shown in Figure 2 (
As shown in FIG. 2(B), images of normal television broadcasting are projected on the central part 1a of the picture tube 1, and the images are projected on the entire picture tube 1 as shown in FIG. 2(B). No raster is formed on the left and right ends 1b and 1c shown.

Problems to be Solved by the Invention As mentioned above, when projecting ordinary television broadcast images onto a large-area picture tube 1 with an aspect ratio of 3:5, the left and right ends 1b and 1c of the picture tube 1 are There was a problem in that a raster was not formed, giving the viewer a sense of discomfort. In addition, the raster end portions of the image projected on the center portion 1a (the center portion 1a and the left and right end portions 1
b, 1c) is usually the solid line work a in Figure 2 (B),
However, depending on the content of the displayed image, it changes as shown by the broken lines IIa and IIb in FIG. This occurs because the raster horizontal amplitude changes due to changes in image brightness if the stability of the picture tube anode voltage and the stability of the deflection circuit are not sufficient for power-saving design. Generally, overscanning is performed by setting the horizontal scanning amplitude to be larger than the width of a picture tube with an aspect ratio of 3:4, so that the raster end portions described above are not displayed on the picture tube with an aspect ratio of 3:4.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image display device that solves the above problems by forming a raster over the entire width of a picture tube even when displaying an image with a small aspect ratio.

Problems to be Solved by the Invention The first invention solves the problem when projecting an image whose width-to-height ratio is smaller than the aspect ratio of the picture tube, when near the start and/or near the end of the video period of this image signal. The horizontal deflection is performed at a high scanning speed to scan the entire width of the picture tube. Also,
The second invention also varies the brightness or color of the picture tube during a large period of scanning speed.

In the first aspect of the invention, the entire width of the picture tube in the horizontal direction is scanned when displaying an image with a small horizontal to vertical ratio, thereby forming a raster over the entire surface of the picture tube. Further, in the second aspect of the present invention, the brightness or color of the left and right ends of the picture tube when the image is projected is varied to eliminate the difference from the image at the center of the picture tube.

Embodiment FIG. 1 shows a 10-system system diagram of an embodiment of the apparatus of the present invention. In the figure, 10 is a terminal to which a video signal comes in, and when receiving a normal television broadcast signal, a video signal a as shown in FIG. 3(A) obtained from this broadcast signal is sent to the terminal 10.
The signal is then supplied to the video processing circuit 11. The video signal processing circuit 11 separates and amplifies the luminance signal from the supplied video signal a, performs color demodulation of the carrier color signal to obtain a color difference signal, and performs matrix synthesis of the luminance signal and color difference signal to generate 3 Take out the three primary color signals R, G, and B. The primary color signals R, G, and B are separately output from primary color signal output circuits 12.13.
14 respectively. The primary color signal output circuit 12 adds, mixes and amplifies the supplied primary color signal R with an additional signal d from an 'R flow modulation circuit 15, which will be described later, and the primary color signal R obtained here is sent to the cathode KR of the picture tube 16. Supplied. Similarly, the primary color signal output circuits 13 and 14 add and mix the applied signals to the supplied primary color signals G and B, respectively, and the obtained primary color signals G and B are sent to the cathode K G * K of the picture tube 16 .
e is supplied to each. This picture tube 16 has an aspect ratio of 3:5.

The above-mentioned video signal processing circuit 11 uses a built-in synchronization separation circuit to separate the horizontal synchronization signal from the video signal a, and then separates the horizontal synchronization signal from the video signal a.
Supply to 7. A control signal indicating whether the video signal a is from a normal television system or a high-definition television system is input to the terminal 18, and is supplied to the regulator circuit 19 and the current modulation circuit 15, respectively. The regulator circuit 19 is supplied with voltage +Es+ from the DC power supply 20, and obtains different voltages depending on whether the control signal instructs a normal television system or a high-definition television system, and sends this to the horizontal deflection circuit 17. supply This is because the scanning speed of a high-definition television system is approximately twice that of a normal television system, and therefore a higher voltage is required than when displaying images of a normal television system. here,
Voltage +282 in normal TV system video display
is supplied to the horizontal deflection circuit 17.

The horizontal deflection circuit 17 generates a deflection current synchronized with the horizontal synchronization signal and supplies it to the horizontal deflection coil 21 .

This horizontal deflection coil 21 has one end grounded via a current modulation circuit 15. The current modulation circuit 15 always has a constant impedance when a control signal instructing video display in a high-definition television system is received, and changes the impedance when displaying a video in a normal television system. This impedance variation is performed depending on the level of the deflection current, for example, and the deflection current C when displaying images in a normal television system has a waveform as shown in FIG. 3(C). In this FIG. 3(C), when the current level is below le+ and when the current level is above 122, the current modulation circuit 1
5 has a small impedance.

Incidentally, for comparison with the deflection current C in the present invention, FIG. 3(B) shows a deflection current waveform when obtaining an image as shown in FIG. 2(B). In this conventional deflection current, the blanking period trl of the video signal a is Ill n tb
fl, and the scanning period js+ is set to be shorter than the video period tdS of the video signal a, and the deflection current peak and
The two-peak value IV+ is set to a value corresponding to the width with an aspect ratio of 3:4.

On the other hand, in the deflection current C in the device of the present invention, the retrace period tr2 is set shorter than the blanking period tb2 of the video signal a, the scanning period ts2 is set longer than the video period tds, and the peak-to-peak value IVz is set to a value (TV2→5/41V+) corresponding to the width with an aspect ratio of 3:5. Furthermore, a period tal, t other than the retrace period tr2 within the blanking period tbIl of the video signal a
In each a2, the slope of the deflection current C is the video period tdS.
during this period ta, , t
The scanning speed of a2 is said to be high. As a result, during the video period tdS of the video signal a, an image with an aspect ratio of 3:4 can be displayed with normal dimensions and without distortion as shown in FIG. 4(A). A raster is also formed on the outside between the left and right sides of this image with an aspect ratio of 3:4.

In addition, the current modulation circuit 15 reduces the impedance when the current level is below X21 and when the current level is above f2z within the scanning period jsz of the deflection current C during video display in a normal television system, and also reduces the impedance as shown in FIG. An additional signal d as shown in D) is generated and supplied to each of the primary color signal output circuits 12-14.

This is because the periods ta, , ta2 are within the blanking period tbIl of the video signal a, and the video signal a is at the pedestal level (black level).

This is intended to increase the brightness of ta2 to the same level as the video period tdS.

As a result, an image with an aspect ratio of 3:4 of a normal television system is projected on the center part 16a of the picture receiver @16 shown in FIG. The left and right end portions 16b.

16c is projected with the same brightness as the central portion 16a. Therefore, the viewer does not feel uncomfortable.

Incidentally, the slope of the deflection current in the vicinity of the current levels I to 1.22 of the deflection current C gradually changes with the distance W#. Also in the picture tube 16 shown in FIG. 4(A), the boundary line (broken line 16d) between the center portion 16a and the left and right end portions 16b and 16c.

16e) Each changes depending on the display content of the central part 16a, but as the slope of the deflection current changes gradually as described above, the boundary lines (broken lines 16d and 16e) are not so clear, and the curves of the boundary lines are not easily developed. Visually unnoticeable.

Note that the level of the additional signal d is determined by the primary color signal output circuits 12 to 1.
By arbitrarily setting and supplying the color to each of the four, the left and right ends 16b and 16C of the picture tube 16 can be made white,
Moreover, it can be made into any color other than white. Further, instead of supplying the additional signal d to each of the primary color signal output circuits 12 to 14, the additional signal d is supplied to the first grid electrode G1 of the picture tube 16 to increase the brightness of the left and right ends 16b and 16c. You may do so.

By the way, as the horizontal deflection circuit 17 shown in FIG. 1, the same circuit as the conventional device for obtaining a deflection current as shown in FIG. 3(B) is used, and the current modulation circuit 15 has a current level Fe3
Iez > let ) or below and current level IIl
If the impedance is set to be small when <(IJ!4<l<2) or more, the deflection current C will be as shown in Figure 3 (E).
The waveform will be as shown in .

This deflection current C in FIG. 3(E) is different from the conventional deflection current (FIG. 3(B)) in most periods [b] except for the first period tc and the last period tc2 within the scanning period tsl. They have the same slope, and the slope is large in the period [tCl, jc2, and the scanning speed of this period j(j+, tC2 is large, and its peak-to-peak value is I
It is said to be yz. Further, the current modulation circuit 15 operates when the current level is below Ifls and when the current level is l! within the scanning period tS+. When it is greater than la, an additional signal d shown in FIG. 3(F) is generated.

As a result, the central portion 1 of the picture tube 16 shown in FIG. 4(B)
Most of the image with an aspect ratio of 3:4 is projected on 6F with normal dimensions and no distortion. Of course, the left and right ends 16o of the picture tube 16,
Although the image located at 16h will be stretched and distorted in the horizontal direction, there is no practical problem because general television broadcasting is configured so that there is no important image information at the edges of the image.

FIG. 5 shows a signal waveform diagram in another modification of the device of the present invention. In this case, the current modulation circuit 15 makes the impedance small when the deflection current C is equal to or higher than the current level I2s as shown in FIG.
In the above case, the additional signal d shown in FIG. 5(C) is generated.

This current level IIl's is the blanking period tb of the video signal a of the normal television system shown in FIG. 5(A).
This value corresponds to the start position of fl. As a result, a period [d with a large slope is formed following the video period tdS of the video signal a within the video period tS2. As a result, as shown in FIG. 6, an image of a normal television system is displayed on the left side 16i of the picture tube 16, and an additional image is displayed on the right side 16j.

Of course, in the same way as above, an additional image is displayed on the left side of the picture tube 16.
It may be configured to display images of a normal television system on the right side.

Note that the aspect ratio of the picture tube 16 is not limited to 3:5, but may be any width to height ratio of 4 or more, and is not limited to the above embodiment.

Effects of the Invention As described above, the image display device according to the first invention forms a raster over the entire surface of the picture tube even when projecting an image with a smaller vertical to horizontal ratio than the picture tube. It has the advantage of not causing any discomfort to people.

In addition, in the second invention, since the scanning speed is increased, that is, the brightness or color of the left and right ends of the picture tube is varied, the brightness of the left and right ends and the center part of the picture tube are kept at the same level, which further reduces the sense of discomfort. Furthermore, even if the boundaries at both the left and right ends of the image change depending on the content of the image, the bending phenomenon of the boundaries is not noticeable.

[Brief explanation of the drawing]

FIG. 1 is a block system diagram of one embodiment of the device of the present invention, and FIG.
3 and 5 are waveform diagrams of various circuit parts of each embodiment of the device of the present invention, and FIGS. 4 and 6 are diagrams showing the state of image projection in the conventional device, respectively. FIG. 3 is a diagram showing a state in which an image is displayed in an example. 10.18...terminal, 11...video signal processing circuit,
12-14... Primary color signal output circuit, 15... Current modulation circuit, 16... Picture tube, 17... Horizontal deflection circuit,
19...Regulator circuit, 20...DC power supply, 2
1...Horizontal deflection coil.

Claims (4)

[Claims] (1) In an image display device that displays multiple types of images with different aspect ratios on a picture tube that corresponds to the image with the largest width-to-height ratio, images other than the image with the largest width-to-height ratio are displayed. When displaying, most or all of the video period of the video signal of the image to be projected is horizontally deflected at an appropriate scanning speed to obtain the image, and near the beginning and/or at the end of the video period. The present invention is characterized in that the scanning speed for a portion of the video period and/or a portion of the blanking period of the video signal in the vicinity is increased and horizontal deflection is performed to scan the entire width of the picture tube in the horizontal direction. Image display device. (2) In an image display device that displays multiple types of images with different aspect ratios on a picture tube that corresponds to the image with the largest width-to-height ratio, images other than the image with the largest width-to-height ratio are displayed. When displaying, most or all of the video period of the video signal of the image to be projected is horizontally deflected at an appropriate scanning speed to obtain the image, and near the beginning and/or at the end of the video period. The horizontal deflection is performed by increasing the scanning speed for a portion of the video period and/or a portion of the blanking period of the video signal in the vicinity to scan the entire horizontal width of the picture tube, and the scanning speed is increased. An image display device characterized in that it is configured to vary the brightness or color of a picture tube during a period of time. (3) The image display device according to claim 2, wherein the variation of the brightness or color of the picture tube is an increase in brightness by a predetermined amount. (4) The image display device according to claim 2, wherein the brightness or color of the picture tube is changed by setting a predetermined color.