JPH03177891A - Display system - Google Patents

Abstract

PURPOSE:To connect many displays and to display the same information on the displays by connecting branch circuits in many stages and preventing a display signal from attenuating or shifting in phase. CONSTITUTION:The branch circuits 3, 4, 6, and 7 branch display signals similar to the inputted display signal into two and output them and also compensate the phase of the display signal by phase matching circuits while compensating the attenuation of the signal. One display signal which is outputted is supplied to a following-stage branch circuit and the other display signal is supplied to the displays 15 - 17. Consequently, the same image information is displayed on the respective displays 15 - 17, which can be connected without being affected by the length of a cable which connects the branch circuits 3, 4, 6, and 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a display system, and particularly relates to control for displaying image information on each display in a display system equipped with a plurality of displays. .

[Conventional technology]

2. Description of the Related Art A so-called image search and display device is known in which various image information is registered in a large-capacity storage device such as an optical disk, and at the same time, a search code is used to search for target image information and display it on a display.

For example, one example is the one shown in Japanese Patent Application Laid-Open No. 62-72067.

[Problem to be solved by the invention]

Although the above-mentioned known technology attempts to display image information on one display, recently there has been a demand for displaying image information on a plurality of displays.

One possible display system to meet such demands is one shown in FIG. 5, for example. That is, a plurality of displays 52,
53 and 54, and the display signal 51 is sent to each connector 56 by branching it with a cable.

However, according to such technology, there are physical restrictions on the number of connectors that can be branched into one connector, and there is also a limit on the length of the cable to be connected in terms of signal transmission.

An object of the present invention is to provide a display system including a plurality of displays in which there is no limit to the number of connected displays and there is no attenuation or phase shift of signals for display.

[Means to solve the problem]

To achieve the above object, the present invention provides an image input means such as a scanner for inputting image information, a storage device such as an optical disk for storing the inputted image information, and at least image information output from the storage device. The present invention is realized in a display system that includes a printer that prints the image information, a display that displays at least image information output from the storage device, and a control device that controls these image input means, the storage device printer, and the display. In such a system, the present invention includes a plurality of branching circuits connected in series for sequentially branching a display signal indicating the image information sent from the control device into at least two identical display signals; a display each connected to one output of the circuit, and each branch circuit comprises:
Each display is equipped with a circuit for preventing attenuation of the display signal and matching the phase of the signal, so that the same image information is displayed on each display.

[Effect]

In the above configuration, each branch circuit branches a display signal similar to the input display signal into two and outputs the two, and the display signal is compensated for its phase by the phase matching circuit, and , signal attenuation is compensated. One of the output display signals is given to the next stage branch circuit, and the other one is
Two display signals are provided to the display. With this configuration, the same image information is displayed on each display. Furthermore, since each branch circuit is equipped with means for preventing signal attenuation and phase shift, multiple displays can be connected without being affected by the length of the cable connecting the branch circuits.

〔Example〕

FIG. 1 is a block diagram of an image display system according to an embodiment of the present invention. In FIG. 1, a control device 10 that controls the entire system includes an image input device 11, a printer 12,
and storage device 13 are connected, as well as a plurality of branch circuits 3
, 4, 6.7 are connected in series.

Here, the image input device 11 is, for example, a scanner, and is an image input device that scans and reads an image to be input.
The input image information is compressed in a control device 10 according to a certain algorithm and stored in a storage device 13 such as an optical disk. The printer 12 decompresses and prints the image information read from the storage device 13, for example.

Branch circuits 3, 4 and 6.7 each have a display 15.1.
6.17 is connected to the branch circuit 3, and the keyboard 14 is also connected to the branch circuit 3. Here, the display 15 provided with the keyboard 14 will be referred to as a basic display, and the displays 16 and 17 will be referred to as additional displays. The keyboard 14 includes, for example, function keys, and allows input of a search code for searching image information stored on the optical disc. optical disc 1
The image information retrieved from 3 is decompressed in the control device 10, converted into a display signal, and sent to branch circuits 3 and 4.
, 6.7, and are displayed on the displays 15, 16.17, respectively.

Branch circuits 3, 4, 6.7 branch the input display signal into two identical display signals. Therefore, the display signal sent out from the control bag W1 is transmitted to the branch circuit 3.
is branched and sent to the display 15. At the same time, a similar display signal is output to the other output terminal of the branch circuit 3. And the display signal is sent to branch circuits 4 and 6.
．． 7 to subsequent displays 16 and 17, respectively. Thus, similar image information will be displayed on the displays 15, 16, and 17.

FIG. 2 is a block diagram showing an example of a branch circuit. The display signal 26 sent out by control bag QIIO typically includes a horizontal sync signal, a vertical sync signal, and video data (see FIG. 3). Generally, it is desirable for displays used in image display systems to have high definition.
The scanning time for one dot is as fast as several ns, and data is often transferred in parallel. In this case, a clock is present at the interface to capture data on the display side.

In the case of this embodiment, the display signal 26 is a TTL level digital signal, and consists of one horizontal synchronization signal, one vertical synchronization signal, 16 video data, and one clock for capturing video data.

The relationship between each signal is shown in FIG. The falling edge of the clock is specified to be in the center of the video data, thereby ensuring data capture. Further, the time t□ from the horizontal synchronizing signal to the first data determines the display start position on the display surface.

In FIG. 2, the receiving circuit 21 includes a display signal 26.
I will take it. At this time, the horizontal synchronization signal, vertical synchronization signal, and video data are taken into the latch circuit 22 in synchronization with the above-mentioned clock.

The signal input to the latch circuit 22 is transmitted to the phase matching circuit 2.
3 to transmitting circuits 24.25, and output from the transmitting circuits 24.25 as output signals 27.28.

The contents of these output signals 27 and 28 are as follows:
4. ．． The output signal 27 is the same as the display signal 26 input to 6.7, and the output signal 27 is, for example,
．． 17, and the output signal 28 is sent to, for example, a branch circuit at the next stage.

The present invention is intended to display display signals without being limited by the length of cables connecting branch circuits and without phase shift on any display. Therefore, the electrical signal levels of the output signals 27 and 28 are compensated for the signal attenuation caused by the cable, and the phases of the output signals 27 and 28 are matched with the input signal 26. For this purpose, a phase matching circuit 23 is provided.

FIG. 4 shows a circuit diagram of the phase matching circuit 23 according to an embodiment of the present invention. In this figure, 44 is a block that integrates the transmission circuit 24 shown in FIG. 3 in the nth stage, the receiving circuit 21 shown in FIG. 3 in the n+1 stage, and a cable that connects both circuits.

Before the output signal of the n-th stage latch circuit 41.42 becomes the input to the n+1-stage latch circuit 45.46, a buffer is required to compensate for the difference in propagation delay time of the elements used and to match the phases of the data and clock. Circuits 23a to 23c and knot circuits 23d to 23e are provided. That is, when the total delay time of the data system is smaller than the total delay time of synchronization signals such as horizontal and vertical synchronization signals, the buffer circuits 23a to 23c are provided for the data system signal, that is, the video data, for a time that can be guaranteed by calculation. Insert and delay the signal.

In the clock system, knot circuits 23d to 23e and buffer circuits 23a to 23c are inserted in order to change the phase by 90 degrees and similarly match the delay time.

Since each signal is latched in the latch circuit 22 described above at the falling edge of the clock, the output of the latch circuit is converted into a signal whose change point is the falling edge of the clock. Therefore, the phase adjustment circuit 23 adjusts the phase so that the falling edge of the clock is placed at the center of the data.

Furthermore, the phases t□ are matched so that the propagation delays of the data system signal and the synchronization system signal are equal. In this way, the phase matching circuit 23 prevents signal attenuation and also prevents phase shift.

According to this embodiment, it is only necessary to connect branch circuits according to the number of displays to be connected, and in order to extend the cable connection distance, without connecting any displays, the cable is connected for the required distance and the above-mentioned branch circuit is connected. Circuits can also be connected in multiple stages.

Let the length of the cable between the branch circuits be Q (m) 4 If n stages are connected, nxg(m) is obtained.

〔Effect of the invention〕

According to the present invention, by connecting branch circuits in multiple stages,
By preventing display signal attenuation and phase shift, these effects do not affect the next stage, so any number of displays can be connected.

Furthermore, since the same signal as that displayed on the basic display can be extracted and applied to the next display, the same information can be displayed on multiple displays.

[Brief explanation of drawings]

FIG. 2 is a block diagram of an image display system according to an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a branch circuit,
FIG. 3 is a signal diagram showing a display signal, FIG. 4 is a circuit diagram showing an example of the phase matching circuit 23, and FIG. 5 is a diagram showing an example of a branch circuit that can be obtained by the prior art. 10...Control device, 13...Storage device. 3.4, 6.7... Branch circuit, 15°16°17... Display, 11... Image input device. 12...Printer. Akira! 2nd Awakening Eye Shinobu 4 Figure

Claims (1)

[Claims] (1) An image input means for inputting image information, a storage device for storing the input image information, a printer for printing at least the image information output from the storage device, and at least an image output from the storage device In a display system having a display that displays information, an image input means, a storage device printer, and a control device that controls the display, a display signal indicating the image information sent from the control device is combined with at least two same display signals. It has a plurality of stages of branch circuits connected in series for sequentially branching to a display, and a display connected to one output end of each branch circuit, and each branch circuit has:
1. A display system comprising a circuit for preventing attenuation of each display signal and adjusting the phase of the signal, wherein the same image information is displayed on each display.