JPH04349492A - Multi-video display system - Google Patents

Abstract

PURPOSE:To eliminate a feeling of discontinuity of a moving picture at an adjacent part and to make an excellent moving picture display by scanning the lower end of an upper image display device screen and the upper end of a lower image display device screen at nearly the same timing. CONSTITUTION:Devices 24-26 of a 2nd stage are rotated by 180 deg., i.e., upside down about devices 27-29 of a 1st stage and devices 21-23 of a 3rd stage. Therefore, scanning directions 34-36 on the 2nd-stage screen are in upside-down and right-left inverted relation with scanning directions 37-39 on the 1st-stage screen and scanning directions 31-33 on the 3rd-stage screen. At this time, the upper-end part of the 2nd-stage screen and the lower-end part of the 3rd-stage screen are scanned at the contiguous parts of the 2nd stage and 3rd stage at the timing of the end of nearly the same one field to eliminate the feeling of discontinuity of the moving picture at the contiguous part. The contiguous parts of the 1st stage and 2nd stage are in the same situation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-image display system in which a plurality of image display devices are two-dimensionally arranged and a single enlarged image is obtained using the display devices.

0002

[Prior Art] Multi-video display systems, in which image display devices such as television sets are piled up to form a single screen, can easily be thinner and have higher brightness compared to the screen size, so they can be used at event venues, showrooms, etc. It is used. For example, the method of stacking image display devices used in such a multi-video display system and the configuration of a screen enlarger that enlarges the input video signal and supplies it to each image display device are disclosed in Japanese Patent Laid-Open No.
It is described in No. 101481.

0003

An example of television scanning is shown in FIG. The image sending side converts the two-dimensional field image information into electrical signals according to the scanning lines and sends out video signals in time series, and the image display device side assembles the sent video signals into images sequentially according to the scanning lines and displays the image. It is something to do. Such a television scanning method is described, for example, in pages 4 to 7 of the NHK Television Technical Textbook (Part 1) published by the Japan Broadcasting Publishing Association (November 30, 1990).

[0004] Television scanning is normally performed from left to right in the horizontal direction and from top to bottom in the vertical direction, as shown by the arrows in FIG. This scan can be simplified to 1 from the top left to the bottom right.
As shown by the arrows in the book, for example, in the case of a 9-panel multi-image display system in which 9 image display devices are stacked, the scanning direction of each image display device will all be in the same direction as shown by the arrows in Figure 11. . Note that 81 to 89 indicate the nine image display devices mentioned above.

Consider a case in which, for example, a car moving from left to right is displayed on the nine-screen multi-image display system shown in FIG. Since the multi-video display system is not taken into account on the image transmission side, the image of a car on the left side in field 1 moving to the right in the next field 2 is converted into a video signal as one image, as shown in Figure 12. ing. Although there is no separation between images on the image transmission side screen shown in FIG. 12, for convenience of explanation, the image display device 8
A break corresponding to ~89 is included. For simplicity, only the image display devices 81 and 84 will be explained below.

FIG. 13 shows images displayed on the image display devices 81 and 84 in chronological order. The lower part of the screen of the image display device 81 is displayed at the end of the field, whereas the upper part of the screen of the image display device 84 immediately below is displayed at the beginning of the field. Therefore, at the end of field 1, the image of field 1 on the image sending side shown in FIG. 12 is reproduced. In the next field 2, as shown in FIG. 13, the images on the image display devices 81 and 84 are sequentially replaced with the images in field 2 on the image sending side in FIG. 12 from the top. In other words, the image of field 1 and the image of field 2 coexist. At this time, if we pay attention to the adjacent parts of the image display devices 81 and 84, while the image sending side continues to send the video signal of field 2, the images of field 1 and field 2 are always adjacent, that is, the car is discontinuous. This causes a sense of discomfort in the moving images displayed on the multi-video display system.

An object of the present invention is to reduce the feeling of discontinuity in images that occurs at the upper and lower boundaries of an image display device when displaying a moving image;
An object of the present invention is to provide a multi-video display system that enables high-quality video display.

[0008]

[Means for Solving the Problem] The above object is to make the scan timings of the bottom edge of the screen of the upper image display device and the top edge of the screen of the bottom image display device almost coincide with each other for vertically adjacent image display devices. This is achieved by In other words, as a multi-video display system, for example, a multi-video display device in which vertically adjacent image display devices are installed upside down to reverse the vertical scanning direction, and input video signals are written to a field memory. This is achieved by using a screen enlarger that enlarges and reads out the video signal written in the field memory according to the scanning direction of each image display device.

[0009]

[Operation] FIG. 14 shows the image display devices 81 and 84 when the image display devices 84 to 86 in the middle row of FIG. 11 are rotated 180 degrees and the vertically adjacent image display devices are installed upside down. FIG. 3 is a diagram showing displayed images in chronological order. In this way, by vertically reverse scanning the upper and lower image display devices, the moving image is displayed continuously at the adjacent portions of the lower edge of the upper image display device screen and the upper edge of the lower image display device screen. A multi-video display screen with less discontinuity can be realized.

0010

[Example] A multi-image display system that combines multiple image display devices to form one screen has various numbers of image display devices, but an example is a so-called 9-screen multi-image display system that uses nine image display devices. Embodiments of the present invention will be described below with reference to the drawings, taking up a video display system.

FIG. 1 is a block diagram showing an embodiment of a nine-screen multi-video display system to which the present invention is applied. The 9-screen multi-video display system includes 9 image display devices 21 to 29.
After writing the input video signal into the field memory 111, the multi-video display device that combines the 9 image display devices 21 to 29 to form one screen is It consists of a screen enlarger that enlarges and reads out the video signal written in the field memory. In addition, 10 is an A/D converter, 112 is a D/A
Converter, 113 is a write address generation circuit, 114 is a read address generation circuit, 91 is a synchronization control circuit, and 11 to 19 are enlarged video signal generation units.

In FIG. 1, the multi-video display device includes 1
The image display devices 24 to 26 in the second tier are rotated 180 degrees with respect to the image display devices 27 to 29 in the tier and the image display devices 21 to 23 in the third tier. Therefore, in the scanning direction of each screen, 1
In contrast to the scanning directions 37 to 39 of the screen in the third stage and the scanning directions 31 to 33 of the screen in the third stage, the scanning direction 34 of the screen in the second stage is
~36 are reversed both vertically and horizontally. At this time,
Assuming that the horizontal and vertical scanning timings of all image display devices are the same, there will be two
Since the upper end of the 3rd stage screen and the lower end of the 3rd stage screen are scanned at almost the same timing at the end of one field, as explained above with reference to FIG. The sense of continuity can be eliminated. Similarly, in the adjacent parts of the first and second stages, the top edge of the first stage screen and the bottom end of the second stage screen are scanned at approximately the same timing at the beginning of one field, so the image display device It is possible to eliminate the sense of discontinuity in moving images in adjacent areas.

Next, a screen enlarger section that forms a video signal to be supplied to a multi-video display device will be explained. The analog video signal input to the multi-video display system is
After the signal is converted into a digital video signal by a /D converter, it is written into each field memory 111 of the enlarged video signal generators 11 to 19 according to the output address of the write address generation circuit synchronized with the input video signal. This field memory 1
11 is read out according to the output address of a read address generation circuit synchronized with the scanning directions 31 to 39 of the corresponding image display devices 21 to 29, and
The A converter 112 converts the signal into an analog video signal and supplies it to each image display device. The synchronization control circuit 91 is a circuit that forms a synchronization signal to be given to the image display devices 21 to 29. As described above, since the image display devices 21 to 29 only need to scan at the same timing, only one type of synchronization signal timing is required. It only needs to occur.

FIG. 2 is an explanatory diagram showing the timing of field memory addresses generated by the write address generation circuit and the read address generation circuit. The horizontal axis shows time and the vertical axis shows memory addresses. To simplify the explanation, field memory addresses are shown only in the vertical direction, and the horizontal direction is omitted. Further, the field memory is a so-called dual port type field memory having a memory capacity for two fields and having two input/output terminals for writing and reading. The bold arrow 101 in FIG. 2 indicates the memory address generated by the write address generation circuit 113, and the address changes linearly in a sawtooth waveform every two fields. On the other hand, there are three types of memory addresses generated by the read address generation circuit 114.
The arrow 211 indicates the enlarged video signal generators 11 to 13 corresponding to the second-stage image display devices 24 to 23, and the arrow 2 indicates the enlarged video signal generators 14 to 16 corresponding to the second-stage image display devices 24 to 26.
21, the enlarged video signal generating units 17 to 19 corresponding to the first-stage image display devices 27 to 29 are indicated by arrows 231.

The reading order of field 2 will be explained in more detail. In field 1, the video signal written in the field memory 111 is transferred to the next field 2.
In the case of a 9-panel multi-video display system in which three layers are stacked one above the other, the read memory address generation circuit requires three types of vertical addresses, which are obtained by dividing the field memory address into three equal parts. Furthermore, as shown in FIG. 1, the second stage image display device is flipped 180 degrees with respect to the first and third stage image display devices, and the vertical scanning direction is reversed. The read address straight line 221 corresponding to the image display device of the third row has a shape that shows a monotonous decrease compared to the other address straight lines 211 and 231 that show a monotonous increase within the field. What should be noted here is that at the beginning of field 2, the address line 23
The addresses indicated by 1 and 221 are close to each other, and the upper ends of the screens of the first-stage image display devices 27 to 29 and the lower ends of the screens of the second-stage image display devices 24 to 26 are scanned almost simultaneously to form an image. It is a point. Further, at the end of field 2, the addresses indicated by the address lines 221 and 211 are close to each other, and the upper ends of the screens of the second-stage image display devices 24 to 26 and the lower ends of the screens of the third-stage image display devices 21 to 23 are close to each other. They are scanned almost simultaneously to form an image. In other words, as mentioned above, in the adjacent parts of the first and second rows and the adjacent parts of the second and third rows, the upper end of the lower screen and the lower end of the upper screen are scanned at almost the same timing. , it is possible to eliminate the sense of discontinuity of moving images in adjacent parts of the image display device.

Note that it is not necessary to provide the write address generation circuit 113 and the read address generation circuit 114 in all the enlarged video signal generation sections 11 to 19, respectively.
For example, it is clear that the write address generation circuit 113 can be shared as one circuit, and the read address generation circuit 114 can be provided as three circuits for common use in accordance with the three-tiered image display device. It is also clear that the field memory 111 does not need to be provided for the entire screen of each of the enlarged video signal generators 11 to 19, and that a memory capacity that can cover the display screen of each corresponding image display device is sufficient. Further, the field memory 111 may be a frame memory or the like, and the same applies to other embodiments described below.

A second embodiment of a nine-screen multi-video system to which the present invention is applied is shown in FIG. In the configuration of the multi-image display device shown in FIG. 1, the horizontal scanning direction of the second-stage image display device is 1
In contrast to the image display device in the 3rd and 3rd tiers, FIG.
The configuration differs in that the horizontal scanning direction is the same for all image display devices. In the embodiment shown in FIG. 1, for example, the image display devices 24 to 26 are rotated 180 degrees, but as is clear from the above description, the image display devices 24 to 26 are rotated by 180 degrees.
By simply reversing the vertical scanning direction of '~26', the upper edge of the lower screen and the lower edge of the upper screen can be Since the images can be scanned at almost the same timing, it is possible to eliminate the sense of discontinuity of moving images in adjacent areas of the image display device. The operation of the screen magnifier portion is the same as that in the first embodiment, so a description thereof will be omitted.

A third embodiment of a nine-screen multi-video display system to which the present invention is applied is shown in FIG. VTR (Video)
Tape Recorder) and VDP (Video
Disk Player), signal sources 51 and 52 such as a computer, a screen enlarger 50 whose configuration is shown in FIGS. 1 and 3, a video signal switching circuit 53, a control terminal 54, and image display devices 44 to 46 capable of switching the vertical scanning direction. The system consists of a multi-video display device using a second-stage video display. Signal source 5
When expanding one video signal to display the entire screen of the multi-video display device, the video signal switching circuit selects the output video signal of the screen expander based on the control signal input to the control terminal 54. By setting the vertical scanning direction of the second-stage image display device to the direction opposite to that of the first and third stages (that is, reverse scanning from bottom to top), the second implementation can be performed. It is clear that the configuration is similar to that of the example, and that the sense of discontinuity of moving images in adjacent parts of the image display device can be eliminated.

Furthermore, in order to improve the added value of the multi-video display system, a plurality of signal sources 52 are prepared, and the video outputs of these signal sources 52 are appropriately switched by a video signal switching circuit 53 to provide a signal to each image display device. It is desirable that a variety of images can be obtained by providing the information. In this way, unless the vertical scanning of the image display device to which the video signal from the signal source 52 is applied is a forward scanning from top to bottom, the image will be upside down. Therefore, in the third embodiment shown in FIG.
When the video signal switching circuit 53 selects the signal source 52 based on the signal from the control terminal 54, the second-stage image display devices 44 to
46 vertical scanning is switched to forward scanning from top to bottom to obtain an image in which the top and bottom of the image are correct.

Next, examples of image display devices 44 to 46 whose vertical scanning directions can be switched based on control signals will be described. FIG. 5 shows a CRT (Ca
This is an example of the configuration of a (ThodeRay Tube) image display device. 61 is a vertical deflection circuit, 63 is a changeover switch, 65
66 is a control terminal, 66 is a CRT drive circuit, 67 is a blanking circuit, 68 is a vertical deflection coil, and 69 is a CRT. CR
To switch the vertical scanning direction of the T-image display device, a switch 63 is used to change the direction of the current flowing through the vertical deflection coil 68.
This can be easily achieved by switching with .

FIG. 6 shows an example of the configuration of a CRT image display device whose vertical scanning direction can be switched based on a control signal. Figure 5
A current detection circuit 62 and a control circuit 64 are added to the configuration. In the embodiment shown in FIG. 6, if the changeover switch is switched while current is flowing through the vertical deflection coil, a high voltage may be generated across the vertical deflection coil, potentially damaging the vertical deflection circuit or the like. To prevent this, the current detection circuit 62 detects the timing when the current flowing through the vertical deflection coil becomes 0, and the control circuit 64 adjusts the forward scanning and reverse scanning control signals given to the control terminal 65 to the timing when the current becomes 0. By controlling and switching the selector switch 63 in accordance with this, generation of the above-mentioned high voltage is prevented and damage to the vertical deflection circuit is prevented. Furthermore, the control circuit 64 controls the blanking circuit 67 when switching the vertical scanning direction.
The beam current of the CRT 69 is suppressed to prevent image disturbances that occur when switching the vertical scanning direction from appearing on the screen.

FIG. 7 shows an example of the configuration of a matrix type image display device capable of switching the vertical scanning direction. 71 is a vertical scanning start signal forming circuit, 72 is a changeover switch, 73 is a control terminal, 74 is a horizontal driver, 75 is a vertical driver, and 76 is a matrix display panel. Vertical driver 75,
For example, by comprising a bidirectional shift register 77 and a buffer circuit 78 that converts its output level to a level required for a matrix display panel 76 such as a liquid crystal panel, the bidirectional shift register 77 can be used to switch the vertical scanning direction. This can be easily realized by switching the shift direction of the register. Note that the bidirectional shift register has two input terminals, upper and lower, for instructing the start of vertical scanning, and the output signal of the vertical scanning start signal forming circuit 71 is input to the upper input terminal for forward scanning from top to bottom; In reverse scanning from above to above, a changeover switch 72 is required that performs a switching operation according to a control signal input to a control terminal 73 so as to be applied to a lower input terminal.

A fourth embodiment of a nine-screen multi-video display system to which the present invention is applied is shown in FIG. All the image display devices 21 to 23, 2 of the multi-video display device part shown in FIG.
4"-26", 27-29 scanning direction 31-33, 34
36 and 37 to 39 are in the same direction, which is almost the same as a conventional multi-video display device. The feature of the fourth embodiment is that the output synchronization signal of the synchronization control circuit 91 is used for the third stage image display devices 21 to 23 as in the conventional case, whereas the second stage image display devices 24'' to 26 ” and 3
The image display devices 27 to 29 in the rows are provided with a synchronization signal obtained by delaying the output synchronization signal of the synchronization control circuit 91 by a delay circuit 92, and a synchronization signal obtained by further delaying the synchronization signal by a delay circuit 93. It is.

The operation of the fourth embodiment will be explained below with reference to FIG. 8, which shows address generation and synchronization signal timing. The upper part of FIG. 9 shows time on the horizontal axis and field memory address on the vertical axis, as in FIG. 2, and the thick line 10
2 indicates a write memory address generated by the write address generation circuit 113. Here, in order to reduce the memory capacity of the field memory, the write address for each field is changed sequentially during the effective display period when screen display information is contained, and the write address is not changed during the blanking period when screen display information is not contained. An example is shown. Even if 102 in FIG. 9 is a straight line during the flyback period, the same thing can be naturally expected if appropriate changes are made. On the other hand, the three types of read memory addresses generated by the read address generation circuit 114 are indicated by the arrow 2 for the enlarged video signal generation units 11 to 13 corresponding to the third-stage image display devices 21 to 23.
12. Arrows 222 indicate enlarged video signal generators 14 to 16 corresponding to second-stage image display devices 24'' to 26'';
Enlarged video signal generators 17 to 19 corresponding to first stage image display devices 27 to 29 are indicated by arrows 232. Note that VD0 is the vertical synchronization signal waveform of the input video signal, and
D1 is the vertical synchronization signal waveform of the synchronization control circuit 91 that is applied to the third-stage image display devices 21 to 23, and VD2 is the vertical synchronization signal waveform of the delay circuit 92 that is provided to the second-stage image display devices 24'' to 26''. , VD3 is the first stage image display device 27~
29 shows the vertical synchronizing signal waveform of the delay circuit 93 applied to the delay circuit 29. ■、■、■、■ are fields 1, 2, and 2, respectively.
3 and 4 show video signals written to the field memory.

In field 1, the video signal (2) written in the field memory 111 is processed as shown by the read address lines 212 of the enlarged video signal generators 11 to 13.
For example, during the valid display period of field 1, the memory contents of the upper 1/3 field of the screen are sequentially read out and provided to the third-stage image display devices 21 to 23. Subsequently, from the retrace period of field 1 to the effective display period of field 2, the memory contents of 1/3 field in the center of the screen are sequentially read out, as shown by the read address lines 222 of the enlarged video signal generation units 14 to 16. , second stage image display device 24'' to 26''
give to Furthermore, from the effective display period of field 2 to the retrace period and the effective display period of field 3, the memory contents for the lower 1/3 field of the screen are read as shown by the read address lines 232 of the enlarged video signal generators 17 to 19. The images are sequentially read out and applied to the first-stage image display devices 27 to 29. The above operation is repeated for the video input signal of each field to display a moving image. At this time, the vertical synchronizing signal given to each stage, which is synchronized with the video signal given to the image display device of each stage, is delayed by a time TD corresponding to approximately the effective display period, as shown by VD1, VD2, and VD3. A phase relationship is required, and these signals are sent to the synchronous control circuit 9.
1 and delay circuits 92 and 93.

In the above operation, the time at which the lower ends of the screens of the third-stage image display devices 21 to 23 are scanned, the time at which the upper ends of the screens of the second-stage image display devices 24'' to 26'' are scanned, and Since the time at which the lower edges of the screens of the image display devices 24'' to 26'' are scanned and the times at which the upper edges of the screens of the first-stage image display devices 27 to 29 are scanned can be made approximately the same, the adjacent portions of the image display devices This eliminates the sense of discontinuity in moving images. As described above, according to the fourth embodiment, even if the vertical scanning direction of the image display device is not reversed and all scanning is performed in the same direction, multi-image display can be performed by using the image enlarger of the present invention and a plurality of synchronization signals. This has the effect of eliminating the sense of discontinuity of moving images in adjacent areas of the image display device, which is unique to display systems.

In the explanation so far, the embodiment has been explained using a 9-screen multi-video display system as an example, but if it is a multi-video display system of the type that is stacked up and down, it is possible to use a multi-video display system other than 9-screens. It is clear that the present invention can also be applied.

[0028]

According to the present invention, for vertically adjacent image display devices, the bottom edge of the screen of the upper image display device and the top edge of the screen of the bottom image display device can be scanned at approximately the same timing. This has the effect of reducing the sense of discontinuity of moving images in adjacent areas of the display device and providing a multi-video display system that can display good moving images.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a first embodiment of a nine-screen multi-video display system to which the present invention is applied.

FIG. 2 is an explanatory diagram showing address generation timing in the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of a nine-screen multi-video display system to which the present invention is applied.

FIG. 4 is a configuration diagram showing a third embodiment of a nine-screen multi-video display system to which the present invention is applied.

FIG. 5 is a configuration diagram showing an example of a CRT image display device capable of switching the vertical scanning direction.

FIG. 6 is a configuration diagram showing an example of a CRT image display device capable of switching the vertical scanning direction.

FIG. 7 is a configuration diagram showing an example of a matrix type image display device capable of switching the vertical scanning direction.

FIG. 8 is a configuration diagram showing a fourth embodiment of a nine-screen multi-video display system to which the present invention is applied.

FIG. 9 is an explanatory diagram showing address generation and synchronization signal timing in a fourth embodiment of the present invention.

FIG. 10 is an explanatory diagram showing the principle of television scanning.

FIG. 11 is an explanatory diagram showing the scanning direction of a conventional nine-screen multi-image display device.

FIG. 12 is a diagram showing an example of an image on the image sending side.

FIG. 13 is a diagram showing an example of image display of a conventional multi-video display system.

FIG. 14 is a diagram showing an example of image display of the multi-video display system of the present invention.

[Explanation of symbols]

10... A/D converter, 11-19... Enlarged video signal generation section, 21-29, 24'-26', 24"-26", 81-
89... Image display device, 31-39, 34'-36', 34"-36"...Arrow indicating scanning direction, 44-46... Image display device capable of switching vertical scanning direction,
50... Screen enlarger, 51, 52... Signal source, 53, 63, 72... Changeover switch, 61... Vertical deflection circuit, 62... Current detection circuit, 64... Control circuit, 66... CRT drive circuit, 67... Blanking Circuit, 68... Vertical deflection coil, 69... CRT, 71... Vertical scanning start signal forming circuit, 74... Horizontal driver, 75... Vertical driver, 76... Matrix display panel, 77... Bidirectional shift register, 78... Buffer buffer. , 91...Synchronization control circuit, 92, 93...Delay circuit, 111...Frame memory, 112...D/A converter, 113...Write address generation circuit, 114...Read address generation circuit.

Claims (8)

[Claims] Claim 1: A multi-image display system in which a plurality of image display devices are combined to form one screen, comprising: a multi-image display device in which vertically adjacent image display devices are installed in a positional relationship rotated 180 degrees with respect to each other; The screen enlarger writes the video signal written in the memory into the memory, and then enlarges and reads out the video signal written in the memory according to the scanning direction of each of the plurality of image display devices. Multi-video display system. 2. A multi-image display system in which a plurality of image display devices are combined to form one screen, wherein vertical scanning directions of vertically adjacent image display devices are in a reverse scanning relationship with respect to each other; The screen enlarger is configured to write the input video signal into the memory and then enlarge and read out the video signal written in the memory according to the scanning direction of each of the plurality of image display devices. Features a multi-video display system. Claim 3: In a multi-image display system in which a plurality of image display devices are combined to form one screen, the vertical scanning direction is sequential scanning from top to bottom in even-numbered (or odd-numbered) rows stacked up and down. and a multi-video display device using an image display device that can be switched to reverse scanning from bottom to top, and an image display device in the even-numbered row (or odd-numbered row) after writing the input video signal to the memory. The video signal written in the memory is enlarged and read out according to vertical reverse scanning, and the video signal is written to the memory according to vertical forward scanning for other odd-numbered (or even-numbered) stage image display devices. a screen enlarger for enlarging and reading out the video signal, and each VTR or VD corresponding to the output signal of the screen enlarger and the above-mentioned image display device;
A multi-video display system characterized by being provided with a switching device for switching signals from signal sources such as P. 4. In an image display device comprising a CRT, a deflection coil, and a drive circuit, a control signal is input that instructs either forward scanning from top to bottom or reverse scanning from bottom to top in the vertical scanning direction. An image display device for a multi-video display system capable of switching vertical scanning directions, and a multi-video display system comprising the image display device. . 5. In an image display device comprising a CRT, a deflection coil, and a drive circuit, a control signal is input that instructs either forward scanning from top to bottom or reverse scanning from bottom to top in the vertical scanning direction. a current detector that detects the timing when the current flowing through the vertical deflection coil becomes almost zero, and a timing indicated by the current detector based on the vertical scanning direction instruction given to the control input terminal. An image display device for a multi-video display system capable of switching vertical scanning directions, and a multi-video display system comprising the image display device, characterized by having a switch for switching the direction of current flowing through a vertical deflection coil. 6. In a matrix image display device comprising a plurality of pixels arranged in a two-dimensional matrix, and a horizontal driver and a vertical driver that sequentially drive the plurality of pixels, the vertical scanning direction is a forward scanning from top to bottom and a downward scanning direction. The vertical driver has a control input terminal into which a control signal instructing either reverse scanning from above to upward is input, and a bidirectional shift register that can switch between forward scanning and reverse scanning according to the instruction of the control input terminal. An image display device capable of switching vertical scanning direction. 7. A multi-image display device that combines a plurality of image display devices to form one screen; In a multi-image display system comprising a screen enlarger which enlarges and reads out a video signal written in the field memory, the timing for reading out the video signal to be applied to the image display device is determined by a screen enlarger arranged immediately above the screen enlarger. 1. A multi-video display system comprising a field memory read address generation circuit that delays the timing of reading video signals applied to an image display device. 8. In a multi-image display system in which a plurality of image display devices are combined to form one screen, the lower end of the display of the upper image display device and the 1. A multi-image display system comprising a multi-image display device in which the light emission timing or scanning timing of the upper end of the display section of the image display device is substantially matched.